Getting Astigmatism in Focus with Advanced Imaging Four Cases Provide Insight Into the GP Experts Diagnosing and Managing Patients 8 with the Latest Options

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— MAY/JUNE 20190119 — — — — REVIEW OF CORNEA — & CONTACT LENSES — — — THE IRREGULAR CORNEA — — GETTING — — ASTIGMATISM IN — — — — — — F CUS — — WITH ADVANCED IMAGING, PAGE 16 — — • Fitting the Irregular Cornea: Nuts and Bolts, PAGE 22 — • Does CXL for Keratoconus Improve Contact Lens Success?, PAGE 28 — EARN 1 CE CREDIT: Pathologic Causes of Irregular Astigmatism, PAGE 30 • — — — — — ALSO: ARVO 2019 HIGHLIGHTS • HOW CONTACT LENS WEAR DISRUPTS THE TEAR FILM — — RCCL0619_Coopervision Clariti.indd 1 5/29/19 9:43 AM contents Review of Cornea & Contact Lenses | May/June 2019

departments features Highlights from ARVO 2019: 4 News Review Abstract Review The Dry Eye-Neuro Link; Get the scoop on new research that Contact Lens Rule Update may change your approach to many aspects of anterior segment care. By Review of Optometry staff My Perspective 10 7 The Mystique of Conjunctivochalasis By Joseph P. Shovlin, OD Getting Astigmatism in Focus with Advanced Imaging Four cases provide insight into The GP Experts diagnosing and managing patients 8 with the latest options. Spirits in the Material World 16 By S. Barry Eiden, OD By Robert Ensley, OD, and Heidi Miller, OD

Corneal Consult Fitting the Irregular Cornea: 44 Nuts and Bolts Trust the Process Here’s a beginner’s guide to help you By Aaron Bronner, OD get started. 22 By Lindsay A. Sicks, OD 46 Fitting Challenges The More the Merrier Does CXL for Keratoconus By Vivian P. Shibayama, OD Improve Contact Lens Success? A review of the literature shows scant evidence for this eff ect. 48 Practice Progress 28 By Brian Chou, OD, and John Gelles, OD Special Considerations for Specialty Lenses By Mile Brujic, OD, and David Kading, OD CE — Pathologic Causes of Irregular Astigmatism The Big Picture Thin is in—but not in 50 the cornea. Here’s a Spread Too Thin 30 rundown of non-inﬂ ammatory corneal By Christine W. Sindt, OD thinning disorders that lead to irregular astigmatism. By Thomas Stokkermans, OD, PhD

Contact Lens Wear and its Disruption of the Tear Film A better understanding of the intricacies of the tear ﬁ lm can help put patients’ discomfort and other issues 38 into better context. By Karen Walsh, BSc(Hons), PGDip, Jaya Dantam, PhD, and Doerte Luensmann, PhD

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 3 RRCCLCCL News Review REVIEW OF CORNEA & CONTACT LENSES

11 Campus Blvd., Suite 100 Newtown Square, PA 19073 Telephone (610) 492-1000 Fax (610) 492-1049 Editorial inquiries: (610) 492-1006 The Dry Eye-Neuro Link Advertising inquiries: (610) 492-1011 Email: [email protected] recent study suggests compared with controls, researchers EDITORIAL STAFF nerve dysfunction may said. This suggests dry eye symp- EDITOR-IN-CHIEF be the root cause of dry toms in those with migraine may Jack Persico [email protected] MANAGING EDITOR Aeye symptoms in some be driven by nerve dysfunction, not Rebecca Hepp [email protected] patients with migraines.1 ocular surface abnormalities.1 ASSOCIATE EDITOR Catherine Manthorp [email protected] Researchers evaluated symp- ASSOCIATE EDITOR toms and signs of dry eye—in- HYPERSENSITIVE CORNEAS Mark De Leon [email protected] CLINICAL EDITOR cluding those suggestive of nerve Short tear fi lm break-up time dry Joseph P. Shovlin, OD, [email protected] dysfunction—in 250 individuals, eye (sBUT), a subcategory of evap- ASSOCIATE CLINICAL EDITOR Christine W. Sindt, OD, [email protected] including 31 who met International orative dry eye, may signifi cantly EXECUTIVE EDITOR Classifi cation of Headache affect patient complaints of ocular Arthur B. Epstein, OD, [email protected] 2 CONSULTING EDITOR Disorders criteria for migraine based pain, new study found. Patients Milton M. Hom, OD, [email protected] on a validated screening.1 with sBUT dry eye—an sBUT of <5 GRAPHIC DESIGNER Ashley Schmouder [email protected] The study found individuals with seconds, a normal Schirmer test and AD PRODUCTION MANAGER migraine were signifi cantly younger few epithelial lesions—were hyper- Scott Tobin [email protected] and more likely to be female com- sensitive to corneal pain, suggesting BUSINESS STAFF pared with the controls. Patients corneal hyperalgesia could partly PUBLISHER James Henne [email protected] with migraine also had more severe account for subjective symptoms in REGIONAL SALES MANAGER dry eye symptoms and ocular pain patients with sBUT dry eye.2 Michele Barrett [email protected] REGIONAL SALES MANAGER compared with the control group. The study enrolled 60 patients Michael Hoster [email protected] Individuals with migraine had with sBUT dry eye and 46 healthy VICE PRESIDENT, OPERATIONS Casey Foster [email protected] a different dry eye symptom—but controls. Patients with sBUT dry eye a similar dry eye sign—profi le had higher corneal pain sensitivities EXECUTIVE STAFF CEO, INFORMATION SERVICES GROUP than healthy subjects but similar Marc Ferrara [email protected] corneal tactile sensations. In the SENIOR VICE PRESIDENT, OPERATIONS Contact Lens Rule Update Jeff Levitz [email protected] 36% of patients with sBUT dry eye The Federal Trade Commission (FTC) is SENIOR VICE PRESIDENT, and corneal hyperalgesia, defi ned HUMAN RESOURCES seeking additional input on its next phase Tammy Garcia [email protected] of proposed changes to the Contact Lens as a pain sensitivity ≥40mm, the VICE PRESIDENT, Rule. Elements of the latest proposal: team observed a strong signifi cant CREATIVE SERVICES & PRODUCTION • Prescribers must satisfy the “Confi r- Monica Tettamanzi [email protected] mation of Prescription Release” with correlation between the subjective VICE PRESIDENT, CIRCULATION a signed confi rmation statement by Emelda Barea [email protected] pain score and the objective corneal CORPORATE PRODUCTION MANAGER the patient; a prescriber-retained John Caggiano [email protected] copy of the prescription signed by the pain sensation. For the entire cohort patient; a patient-signed copy of the they found a weak positive correla- EDITORIAL REVIEW BOARD sales receipt confi rming they received tion between the subjective pain Mark B. Abelson, MD the prescription; or proof that they James V. Aquavella, MD received a digital copy. score and the objective corneal pain Edward S. Bennett, OD 2 • Prescribers must give a copy to the pa- RCCL Aaron Bronner, OD sensation. Brian Chou, OD tient’s designated agent upon request. Kenneth Daniels, OD • Robocall information must be delivered 1. Farhangi M, Diel R, Buse DC, et al. Individuals with S. Barry Eiden, OD slowly, at a reasonable volume and migraine have a diff erent dry eye symptom profi le Desmond Fonn, Dip Optom, M Optom allow prescribers to repeat it. than individuals without migraine. Br J Ophthalmol. Gary Gerber, OD Robert M. Grohe, OD • A seller must send the prescriber a ver- April 30, 3019. [Epub ahead of print]. 2. Tagawa Y, Noda K, Ohguchi T, et al. Corneal hy- Susan Gromacki, OD ifi cation request with the manufacturer peralgesia in patients with short tear fi lm break-up Patricia Keech, OD name or brand if diff erent than the one time dry eye. The Ocular Surface. 2019;17(1):55-9. Bruce Koffler, MD specifi ed. Pete Kollbaum, OD, PhD Jeffrey Charles Krohn, OD • Sellers must provide a way for patients Advertiser Index Kenneth A. Lebow, OD to present their prescriptions directly Jerry Legerton, OD to the seller. Alcon ...... 13, Cover 3 Kelly Nichols, OD Bausch + Lomb ...... 5 Robert Ryan, OD FTC seeks additional public comment on proposed Jack Schaeffer, OD changes to the contact lens rule. www.ftc.gov/news- CooperVision ...... Cover 2 Charles B. Slonim, MD events/press-releases/2019/05/ftc-seeks-additional- Kirk Smick, OD public-comment-proposed-changes-contact-lens. May Menicon ...... Cover 4 Mary Jo Stiegemeier, OD 2, 2019. Accessed May 14, 2019. Oculus ...... 6 Loretta B. Szczotka, OD Michael A. Ward, FCLSA Barry M. Weiner, OD Barry Weissman, OD

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RCCL0619_Oculus.indd 1 5/29/19 3:10 PM My Perspective By Joseph P. Shovlin, OD

The Mystique of Conjunctivochalasis Be vigilant when examining the entire ocular surface to avoid confusion.

t’s likely that, at one point or These two cases keep infl ammatory ointment and patching at night may another, every eye care provid- cytokines (IL-6 and IL-8) on the oc- provide some relief if the CCh is er has diagnosed dry eye and ular surface, increasing the chances severe.1 Also address all additional Ieventually discovered that the of MMP activation and discomfort. confounders, including any ocu- masquerader conjunctivochalasis An additional breakdown of con- lar-related allergy, meibomian gland (CCh) was actually the cause of junctival elasticity and progression disease and blepharitis. their patient’s discomfort. How of CCh is possible.1 Surgery is a reasonable option many times have we placed punctal An interesting study performed in when targeted medical management plugs in the inferior punctum with 2015 at a Veterans Affairs hospi- fails. Several approaches to offer no relief from symptoms—some- tal showed the location of CCh to patients are conjunctival excision times making the symptoms even be important. The study analyzed with Tisseel (fi brin sealant, Baxter worse? CCh is just one of several the relationship between CCh and Healthcare), conjunctival fi xation to mechanical conditions that affects symptoms and signs of dry eye.3 the sclera (incisional glue), amni- the ocular surface, and most provid- Patients with nasal CCh had the otic membrane transplantation ers commonly overlook it. most severe symptoms by OSDI and superfi cial thermocautery.2 As we age, CCh, or loose re- scores when compared with patients Radiofrequency treatment will dundant conjunctiva, becomes a with CCh elsewhere or no CCh at generally be less traumatic to the common sign of ocular surface all. Nasal CCh patients also had ocular surface than thermocautery. degradation.1 Its etiology is certainly a more abnormal tear fi lm with Re-establishing the fornix is key to multifactorial. In addition to age, decreased Schirmer scores, increased avoid scarring and the development a history of dry eye, allergies (eye meibomian gland dropout and of a cicatricial entropion.1 rubbing), certain medications and increased eyelid vascularity.3 Those previous surgeries are risk factors with nasal CCh experienced more o, is CCh its own clinical entity, for CCh and can cause a wide vari- throbbing and light sensitivity than Sa masquerade of dry eye or just ety of symptoms.2 Symptoms can be those with non-nasal CCh.3 an extension of it, since the eye can non-specifi c with an insidious onset, Placing a fi nger on the area only respond with so many symp- which is why CCh is often confused that the patient describes as being toms? Regardless of what camp you for dry eye.2 painful and having them look fall in, this is a condition that can’t It’s fascinating that some of the up and down will reproduce the be missed but unfortunately often is. worst cases (with signifi cant pleat- characteristic pain and aid in a CCh remains the most common ing and prolapse) I’ve ever seen are helpful diagnosis.4 reason for recurrent subconjunctival totally asymptomatic, yet some with hemorrhages, causes a wide range only minimal CCh inferiorly have TREAT AND MANAGE of symptoms, including signifi cant tremendous discomfort from the Most often, the extent of signs and tearing, burning and irritation in mechanical irritation and disruption symptoms that present to the offi ce many older patients, and is easily of their tear fi lm.2,3 affects how we manage CCh. Some treated in-offi ce. The mystique In its most severe forms, CCh patients with very dramatic presen- remains, but, fortunately, we have can cause blurred vision, mucus tations might have no complaints good remedies to treat CCh when discharge, fatigue, dryness, tearing and require no treatment, just obser- not overlooked. RCCL and subconjunctival hemorrhage.2 vation. If the patient is symptomat- 1. Bert BB. How to manage conjunctivochalasis. Rev Epiphora secondary to CCh is ic, topical agents, such as artifi cial Ophthalmol. 2017;24(9):36-38. thought to be due to two distinct tears, antihistamines and steroids, 2. Lozano AFI, Larrazaabal LI. Conjunctivochalasis. eye- wiki.aao.org/Conjunctivochalasis. Last modifi ed March, causes: (1) reduplicated folds of con- are a reasonable approach. 13, 2019. Accessed April 1, 2019. junctiva disrupt the tear lake or (2) The goal is to reduce any disrup- 3. Chhadva P, Alexander A, McClellan, et al. The impact of conjunctivochalasis on dry eye symptoms and signs. the conjunctiva causes a mechanical tion of the tear fi lm and infl am- Invest Ophthalmol Vis Sci. 2015;56(5):2867-71. blockage of the inferior punctum.1 matory chemical mediators. Using 4. Hovanesian J. March 2019. Personal communication.

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 7 The GP Experts By Robert Ensley, OD, and Heidi Miller, OD

Spirits in the Material World What a lens is made of has huge implications for your ability to achieve a successful ﬁ t.

cleral gas per- sifying GP lenses based on meable contact Dk, they can be split into lenses have seen a three categories: low Dk (25 Ssurge in popularity to 50), high Dk (51 to 99) over the past decade, but and hyper Dk (≥100).1 they have been evolving However, the amount since the late 19th centu- of oxygen transmission ry. Practitioners, past and through an individual present, learn the options lens is also dependent on at their disposal and make the thickness of each lens the best choices for their (Dk/t). If lenses are made patient’s benefi t. Follow in with identical materials and their footsteps and be cog- Dk values, the Dk/t will nizant of the various factors Patients with ocular surface disease or an unstable tear decrease with increasing that make up today’s GP fi lm may suff er from poor surface wettability. center thickness. lens materials. Surface wettability. Glass remained the primary higher Dk, silicone is inherently This refers to how well the tear material used to design contact hydrophobic, which may result fi lm spreads across the contact lens lenses from 1887 until 1936, when in poor wettability and a surface surface. Disruption or evaporation William Feinbloom manufactured a prone for deposition. Wetting agents of the tear fi lm from the anterior scleral lens that combined glass and and crosslinking agents can also surface can increase deposition and plastic to make the lens thinner and be added to the polymer to attract may affect both the quality of vision easier to wear.1 water molecules and increase the and comfort of the lens. In 1948, Kevin Tuohy’s patent rigidity, respectively.1 Similar to the effect of a reduced for what would become the fi rst The next generation of GP lenses tear break-up time, a GP lens that corneal contact lens described a lens added fl uorine, which, in addition does not have an even tear layer will made from polymethyl methacry- to being more resistant to depo- cause fl uctuating vision that is often late (PMMA).1 The lens design had sition, also aids in oxygen trans- described as foggy or smeared. In blunt edges and fi tted fl atter than mission.1 Fluoro-silicone/acrylate vitro, wettability is measured by the current methods but rested entire- (F-S/A) materials have less silicone, wetting or contact angle. For GP ly on the corneal surface. PMMA allowing increased stability of the lenses, the wetting angle is measured remained the primary rigid lens lens while still retaining a high level by captive bubble technique. material until the introduction of of oxygen permeability. Their specif- When a GP lens is submerged in the more oxygen permeable sili- ic characteristics vary, but the vast water, the wetting angle is formed cone-based lens in 1979.1 majority of GP materials being used between the surface of the lens and today are F-S/A polymers. an air bubble placed on the surface MODERN MATERIALS by a syringe. A wetting angle of zero To improve the nonexistent oxygen MATERIAL PROPERTIES would be a completely wettable permeability (Dk) of PMMA lenses, Designing GP lenses is a fully surface, so lower wetting angles are silicone side branches were added customizable process. Base curve, desirable.3 Nevertheless, wetting an- to the methacrylate monomer, diameter and power are paramount gles and clinical performance don’t increasing the space between the to an order, and material choice can always correlate, since tear fi lm polymer chain and allowing for an easily become an afterthought. To chemistry can affect lens wettability. increased fl ow of oxygen.1,2 While choose a material, a basic familiarity Even with lower wetting angles, lenses made from this silicone/ with material properties is essential. patients with ocular surface dis- acrylate (S/A) copolymer have a Oxygen permeability. When clas- ease or an unstable tear fi lm may

8 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 still suffer from poor wettability. corneal health should be at the fore- Lens thickness may also affect These patients may benefi t from the front of every scleral fi t, especially lens mass, which can be increased or addition of Hydra-PEG (Tangible with diseased and compromised decreased by changing SG and RI. Science) coating. corneas. The larger diameter lens To improve centration, a high-rid- Specifi c gravity and refractive in- will vault over the cornea, and the ing, lid-attached fi t may need a dex. Specifi c gravity (SG) is the ratio stagnant fl uid reservoir will slow larger, heavier lens, while a low-rid- of the density of a solid, in this case the diffusion of oxygen, depending ing or interpalpebral fi t may need the GP lens, to the density of equal on the varying amount of clearance a lens with less mass. Despite the volume of water (SG=1.00) at the beneath the lens. smaller surface area, if patients have same temperature. Materials with Hyper-Dk materials are chosen as a poor tear fi lm or have trouble a higher SG will therefore have a a default, but certain ocular condi- with their cosmetics, wettability and greater mass. Changing the SG can tions where hypoxia is of greatest deposition can be an equal nemesis affect the lens mass by up to 20%.4 concern, such as post-penetrating to corneal GPs. Similar to spectacle lenses, a GP keratoplasty or limbal stem cell If plasma treatments or Hydra- lens with a higher refractive index defi ciency, will require the highest PEG are considered, keep in mind (RI) will be thinner, which can oxygen permeability available. that not all cleaning and care reduce lens mass. A higher RI can Higher-Dk lenses tend to have less regimens are compatible with these. also produce a higher add power on silicone, therefore tend to have a If patients are set in their ways with a front surface aspheric multifocal.5 lower modulus and lower durability. an abrasive cleaning regimen or tap Hardness and modulus. The Depending on the thickness of the water rinse, choosing a material hardness of plastics, including GP lens and the haptic system, these with lower silicone may improve the lenses, can be measured using the lenses may be more prone for fl ex- wettability before adding plasma Rockwell R or Shore durometer ure or torsion. treatments or Hydra-PEG. methods. The two tests measure Advise patients with scleral lenses the resistance to indentation from on the proper care regimen to avoid nfortunately, experience will various weighted loads. Although scratching the lens surface or warp- Uremind us there is no material neither test can predict strength or ing the lens. The greater surface area that can be universally used for scratch resistance, they can suggest of scleral lenses also increases the every patient, but understanding a higher degree of durability. Shore importance of surface wettability. each one’s properties can help us hardness can also serve as a general With corneal GPs, pay attention make the best choice. RCCL indicator for modulus.6 Modulus to the patient’s ocular anatomy, 1. Bennett ES. Gas-permeable material selection. describes the fl exibility of a material, tear fi lm, refractive error and visual In: Bennett ES, Henry VA, eds. Clinical Manual of with a higher modulus resulting in demands. Lens centration, comfort Contact Lenses. 4th Ed. Philadelphia, PA: Lippin- cott, Williams & Wilkins; 2014:89-111. a stiffer lens. Lower modulus lenses and optics tend to be more import- 2. Musgrave CSA, Fang F. Contact lens materials: may cause fl exure, especially on an ant factors leading to a successful A materials science perspective. Materials. astigmatic cornea. outcome. Tear exchange will often 2019;12(2):261. 3. Campbell D, Carnell SM, Eden RJ. Applicability mitigate the need for a hyper-Dk of contact angle techniques used in the analysis CHOOSING A MATERIAL material, but Dk must be considered of contact lenses, part 1: comparative methodol- While there is no algorithm for when dealing with high refractive ogies. Eye Cont Lens. 2013;39:254-62. 4. Ghormley NR. Specifi c gravity–does it contrib- choosing a material, the approach errors. High myopic powers will ute to RGP lens adherence? Int Contact Lens Clin. will typically differ between scleral have a thinner center thickness, so a 1991;18:125. lenses and corneal GPs. For scleral lower Dk lens may provide a more 5. Bennett ES. GP insights: how high index GP materials will impact your practice. CL Spectrum. lenses, oxygen permeability and stable fi t. Conversely, high hyper- February 2009. surface wettability are arguably the opic lenses will be thicker, making 6. MatWeb material property data. Shore (durometer) hardness testing of plastics. www.matweb. most important considerations for a higher Dk more appropriate to com/reference/shore-hardness.aspx. Accessed choosing a material. Maintaining increase Dk/t. March 19, 2019.

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 9 Highlights from Get the scoop on new research that may ARVO 2019: change your approach to many aspects of ABSTRACT REVIEW anterior segment care. By Review of Optometry staff

he annual Association for While researchers found no was also associated with a 72.7% Research in Vision and statistical difference in age of decreased risk of requiring kerato- Ophthalmology (ARVO) onset between European patients plasty.2 They add that other factors Tmeeting is always a compared with each of the oth- associated with an increased risk boon for the eye care profession. er ethnic groups, they did note for keratoplasty included black Clinicians gain access to an entire that Indians tended to be older at race (vs. white), younger age and year’s worth of research—which onset. The team observed that the lower socioeconomic status of can be both exciting and daunting. mean anterior corneal curvature a participant’s residential neigh- Here, we have selected studies was fl atter among Europeans, and borhood.2 “Scleral lenses have we feel may be most impactful the spherical equivalent was least changed the treatment paradigm for practicing optometrists and severe. The mean corneal pachym- in managing patients with non-in- reviewed a handful of abstracts. etry was thinner among Indians fl ammatory thinning disorders, While the new tools, therapies and than Europeans and Asians at the such as keratoconus, primarily management strategies recapped apex and the thinnest location.1 because they provide exception- here only give a small taste of the “These fi ndings have import- al comfort and vision,” says Dr. fi ndings showcased in Vancouver, ant clinical implications when Shovlin. “Most transplants are even this brief showcase—15 interpreting studies from differ- a result of patients not achieving abstracts in all—packs in many ent regions and contribute to the comfort or adequate vision with exciting new ideas. understanding of risk factors and contact lens correction.” future management strategies of Investigators from Japan say KERATOCONUS keratoconus,” the study authors accelerated corneal collagen cross- Several researchers took a close conclude.1 linking (A-CXL) has the added ben- look at the pathophysiology and “A global registry would be efi t of causing less haze and fewer management of keratoconus: helpful to defi ne additional differ- long-term risks of continuous Pathophysiology. A team of ences that may aid in patient man- fl attening. Doctors and patients researchers found that keratoconus agement,” says Joseph Shovlin, alike have reason to prefer the patients with a European OD, of Northeastern Eye Institute A-CXL protocol, they feel, because background presented with in Scranton, PA. it reduces procedure time, as long less severe indicators of disease Management. Researchers as outcomes aren’t compromised compared with keratoconus recently found that patients who relative to conventional CXL.3 patients of Indian or Asian descent. wear scleral contact lenses for The team of researchers looked This observational study recruited keratoconus had a signifi cantly at 22 eyes of 21 progressing keratoconus patients from public lower risk of requiring keratoplas- keratoconus patients who and private ophthalmology clinics ty, which may warrant the lenses’ underwent epithelium-off CXL in Australia, Hong Kong and wide-scale use for the condition.2 treatment. Twelve eyes of 11 India. The team evaluated 1,472 The team noted that 2.03% of patients underwent conventional eyes of 736 patients. Of these, patients wearing scleral lenses CXL, which involves a 0.1% 55% were European, 18% were required keratoplasty, compared ribofl avin instillation and a Asian, 18% were Indian and 9% with 6.82% of those who did not 3.0mW/mm2 UVA irradiation were other ethnicities.1 wear scleral lenses.2 Lens wear for 30 minutes. The other 10

10 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 underwent A-CXL, which uses a protein (CRP) and interleukin-19. repeating CXL, and keratoconus higher-intensity 18mW/mm2 UVA The study assessed 40 eyes of 20 stabilized afterward.5 irradiation for only fi ve minutes.3 patients, of which 20 underwent While best-corrected visual A-CXL. Researchers analyzed OTHER CORNEAL acuity (BCVA), thinnest corneal patients one day, one week, one COMPLICATIONS thickness and corneal endothelial month and three months after To help differentiate keratoconus cell densities were similar between the procedure. After one month, from pellucid marginal degener- the two groups, steepest K values they found a more-than-twofold ation (PMD), Iranian researchers were signifi cantly different, with decrease in specifi c cytokines in pa- found that four fundamental the conventional CXL patients tient tears. More proinfl ammatory parameters could be considered as showing more fl attening compared cytokines also began to decrease by diagnostic signs to characterize all with the A-CXL patients at one three months. Researchers believe stages of PMD, including subclini- year—and the difference increased studies with longer follow-up will cal disease:6 through the fi ve-year study period. help prove whether these changes 1. An inferior fl attening island, Also at fi ve years, 58.3% of the last and how they correlate with defi ned as the fl attening area conventional CXL group had fl at- clinical outcomes.4 surrounded by steep areas infe- tening Ks of more than 1D—none A study conducted in Germany rior to the horizontal axis. in the A-CXL group exhibited suggests practitioners examine 2. An apple-shaped pattern the same fi nding. Finally, corneal keratoconus patients at regular formed by mean power area as densitometry was signifi cantly intervals, especially fi ve years after a yellow strip. higher after conventional CXL performing CXL, to recognize 3. Superior fl attest area, defi ned as than A-CXL from one month to and re-treat progression early. the presence of the fl attest area one year after the procedure.3 Researchers defi ned a satisfactory at the superior quadrant. “With similar effi cacy, the response to CXL as a postoper- 4. Against-the-rule irregular astig- abbreviated/shorter version should ative Kmax stabilization of an matism (fl at meridians at 45 to be employed to reduce risk,” says increase of more than 2D or any 135 degrees). Dr. Shovlin. decrease in Kmax. They analyzed Additionally, the investigators Another study discovered that 168 eyes of 131 patients who were noticed that measuring the extent signifi cant changes in the infl am- treated with standard CXL.5 of the inferior fl attening island matory molecular profi le occur After CXL, median K2 in- could be helpful for staging PMD at least one month after CXL. creased by 0.1D after one year and identifying early PMD. Based Researchers from Mexico found but decreased over the remaining on these parameters, investigators decreases in proinfl ammatory 10-year postoperative period were able to differentiate 36 cases cytokines, especially metallopro- by 0.85D. Mean apical corneal of PMD from keratoconus.6 teinase-9 (MMP-9), c-reactive thickness decreased by 11µm, 9µm “Some patients with keratoconus

Photo: Marshall Ford, MD, Pacific Cataract and Laser Institute and 3µm after three, have similar features depending seven and 10 years, on the level of severity,” says Dr. respectively. Mean Shovlin. “The most defi nitive way BCVA signifi cantly to differentiate would be to look increased by 0.14 at higher-order aberrations where after two years and PMD has a high level of trefoil by 0.15 after fi ve and and keratoconus has more vertical 10 years. One, seven coma in general.” and 10 years post- Pterygia are more common on CXL, 87.8%, 81.1% the nasal side of the cornea than and 66.7% of eyes the temporal side—15 times more met the responder likely, to be precise. But researchers criteria, respective- aren’t quite sure why. One group ly. The researchers found that total UV irradiation in A-CXL, which uses a higher UVA irradiation for a re-treated four the nasal limbus is not greater than shorter amount of time, was found to have fewer eyes. There were in the temporal limbus, contrary risks of corneal fl attening. no complications in to popular belief. The team created

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 11 HIGHLIGHTS FROM ARVO 2019: ABSTRACT REVIEW Photo: Andrew Gurwood, OD a sub-nanometer level and estab- Index (OSFI). The noninvasive, lish average thickness and lipid low-tech procedure can help pre- break-up time (LBUT).8 dict postoperative DED, allowing The international team of surgeons and comanaging optom- investigators found that the TFI etrists to perform useful personal- method could accurately diagnose ized preoperative risk assessments. DED with 87% sensitivity and This new method includes 20 clin- 88% specifi city. Of particular ical factors to assess preoperatively interest, the reproducibility of that help to uncover any health the mucoaqueous layer thickness defi cits relevant to dry eye.10 One study disproved the popular peripheral light–focusing eff ect measurement, which has not been Researchers identifi ed three dis- theory for pterygia formation. evaluated with any prior technol- tinct categories: mild frailty (OSFI ogy, was signifi cantly correlated ranging from 0 to 161), moderate a corneal model using custom with Schirmer scoring, and the frailty (162 to 322) and severe software and the corneal surface LBUT scoring was signifi cantly frailty (more than 323). Of the to- and UV refractive index data from correlated with tear break-up time tal study participants, 16.2% devel- a previous study to simulate the (TBUT) scoring.8 oped DED within one month after impact of the UV across the cornea.7 To measure a patient’s tear os- surgery, and the rate signifi cantly “This study essentially rules out molarity, clinicians now have two increased from 10.2% to 38.1% the peripheral light focusing effect options: the Tearlab osmometer from the lowest to the highest frail- theory for pterygia formation,” ex- and the I-Pen (I-Med Pharma) os- ty category. They also discovered plains Dr. Shovlin. The researchers mometer. However, they should be that OSFI (but not age and gender) offer an alternative explanation: careful to avoid using the readings was signifi cantly associated with that the temporal-to-nasal fl ow of interchangeably. Researchers from postoperative DED onset.10 tears over the UV-exposed cornea Ludwig Maximilians University “This is a great example of causes the accumulation of toxins in Munich have found that the precision medicine delivered in a on the nasal limbus.7 I-Pen provides signifi cantly high- personalized fashion by providing “If this theory is correct, ad- er osmolarity results compared a frailty risk assessment to predict ditional ocular surface disorders with the Tearlab device. The team the likelihood of adverse condi- may be explained by the tempo- studied 51 healthy subjects—none tions occurring after a surgical pro- ral-to-nasal tear fl ow dynamics to of whom had clinically evident cedure,” says Dr. Shovlin. facilitate drainage to the punctal dry eye—with each device. They A new approach to identifying area,” adds Dr. Shovlin. speculate that the location of the DED measures the physical prop- testing—tear meniscus vs. the pal- erties of the tear fi lm, particularly DRY EYE pebral conjunctiva—could account the effective extensional viscos- Many of the dry eye advances pre- for the difference.9 ity, which researchers measured sented at ARVO focused on new If clinicians use Tearlab’s cut-off using acoustic rheometry. The diagnostic tools: value of 308mOsm/l for normal Melbourne-based team found this A new hyperspectral imaging osmolarity, 98% of the study metric is compromised in DED. In method can measure the mucoa- participants would be considered addition, a lower effective exten- queous layer thickness as well as normal, compared with only 68% sional viscosity is associated with other tear fi lm functions. The tear when testing with the I-Pen. Thus, more severe DED, and a moder- fi lm imager (TFI) is designed to the researchers conclude that doc- ate positive correlation existed give doctors objective and observ- tors should consider using a higher between effective tear fi lm exten- able measures to aid the diagnosis cut-off value (between 316mOs- sional viscosity and noninvasive and management of dry eye disease m/L and 320mOsm/L) when test- TBUT. The authors believe their (DED). The TFI, which takes ing patients with the I-Pen.9 results support the utility of tear approximately 40 seconds, can To help optometrists and ocular effective extensional viscosity as a measure patients’ aqueous layer surgeons better anticipate iatrogen- novel test for diagnosing DED in thicknesses and averages at a nano- ic dry eye in their patients, Italian clinical practice.11 meter level. Additionally, it can researchers built a new clinical “Other fi elds in healthcare measure the lipid layer thickness at tool, the Ocular Surface Frailty have used rheometry, and this

12 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 Sponsored Content

CLEAR CARE® PLUS SUCCESS MADE SIMPLE William Townsend, OD, FAAO 4 Advanced Eye Care end-of-day comfort . For these very reasons, I myself was an Canyon, TX early user of CLEAR CARE® PLUS and was very impressed by how comfortable my eyes felt throughout the day. When I recom- ® Dr. Townsend was compensated by Alcon for his participation in this testimonial. mend CLEAR CARE PLUS to my patients, they notice it as well. Many of them tell me that when they use CLEAR CARE® PLUS, My practice is located in a hot and dry part of the country, they are able to wear their lenses (regardless of brand) for a where seasonal changes and dry environments pose a full day without discomfort, which complements a recent study signiﬁcant challenge for my patients to maintain comfortable that showed an increase of 3 hours of comfortable wear time ® 4 contact lens wear. For instance, with summer upon us, my per day after using CLEAR CARE PLUS for 30 days. * patients are engaging in more outdoor activities like long walks, One of my nature-loving patients raved about how she can horseback-riding and hiking. Such activities expose them to dry participate in outdoor activities for long periods of time without her air and can really take a toll on their contact lenses getting dry and uncomfortable. Espe- lens wearing experience. While I recommend One of my nature-loving cially in our climate, my patients’ success with lenses with materials and surface technologies CLEAR CARE® PLUS is a true testament that the patients raved about how designed to help increase my patients’ product delivers outstanding all-day comfort.4 she can participate in outdoor comfort, I truly believe that the right lens care My patients love how their lenses feel with activities for long periods solution can go a long way in making contact CLEAR CARE® PLUS, and I can rest assured lens wear more comfortable. To me, of time without her lenses that it gives my patients exceptional protection particularly for all of my weekly and monthly getting dry and uncomfortable. against ocular infections while being easy replacement lens-wearing patients, that for them to use.3,5,6 At the end of the day, ® solution is CLEAR CARE PLUS. satisﬁed patients can translate into a successful practice, and What makes CLEAR CARE® PLUS stand out is the wetting agent, CLEAR CARE® PLUS is the lens care solution that will help make HydraGlyde® Moisture Matrix, which envelops the lens in long- that happen. By recommending that they clean and disinfect lasting surface moisture,1,2 and makes lenses feel like new.3 their lenses daily with CLEAR CARE® PLUS, you will help your As a result, the lenses provide exceptional patients, and ultimately your practice, succeed.

* Symptomatic AIR OPTIX® AQUA contact lens wearers experienced 12.1 hours of comfortable wear time compared to 8.73 hours with their habitual MPS as baseline. References 1. Muya L, Scott A, Alvord L, Nelson J, Lemp J. Wetting substantivity of a new hydrogen peroxide disinfecting solution on silicone hydrogel contact lenses. Poster presented at the British Contact Lens Association 39th Clinical Conference & Exhibition, Liverpool, UK, May 29-31, 2015. 2. Alcon data on file, 2014. 3. Alcon data on file, 2016. 4. Alcon data on file, 2016. 5. Gabriel M, Bartell J, Walters R et al. Biocidal efficacy of a new hydrogen peroxide contact lens care system against bacteria, fungi, and Acanthamoeba species. Optom Vis Sci. 2014;91:E-abstract 145192. 6. Alcon data on file, 2014.

RCCL0619_Alcon CC Adv.indd 1 5/29/19 9:45 AM HIGHLIGHTS FROM ARVO 2019: ABSTRACT REVIEW Photo: Christine Sindt, OD technology may be employed infl uences in biomarkers in even someday as a device marker for more morbid diseases.” identifying DED and stratifying it by severity,” notes Dr. Shovlin. CONTACT LENSES A long-term, high-fat diet may Researchers from the Brien reduce the lacrimal gland’s tear Holden Vision Institute present- secretion ability, which in turn ed new fi ndings that suggest a could cause dry eye, a new study patient’s comfort in contact lenses claims. The investigation included affects their visual satisfaction— Patients who wear sclerals for mice that were given either a stan- and vice-versa. For non-presby- keratoconus had a lower risk of dard or high-fat diet for different opic patients wearing single vision requiring keratoplasty. durations over one to four months. lenses, changes in vision satisfac- After one month, the study found tion affected their comfort rating, foreign body reaction to implant- mice on the high-fat diet had de- but changes in comfort didn’t able polypropylene mesh, but the creased tear secretion.12 necessarily impact their vision application to other devices has This type of diet could induce ratings. The opposite seems to be not yet been established, the study lipid peroxidation, infl ammatory true for those wearing multifocal observes.14 cell infi ltration, mitochondria dam- designs. Changes in their ocular The study found a uniform and age, an increase in cell apoptosis comfort during lens wear led to conformal blue stain remained and proliferation inhibition in the changes in their vision rating more on lenses dipped in oppositely lacrimal gland. This could result than vision changes impacted their charged polymers (compared in aqueous tear secretion decrease, comfort ratings.13 with control lenses), which shows which may induce dry eye, the “Consideration of participant successful application of the researchers said.12 characteristics, visual stimulus polymeric coating to the lens, “Infl ammation and associated and contact lens comfort needs to investigators said. Additionally, structural morbidity has been be accounted for when assessing IL-4 release kinetics from a coated shown to be evident in many DED overall contact lens experience,” lens incubated with enzymes studies, including this one, and explains Dr. Shovlin. “Probably showed a sustained release of IL-4 continues to drive home the point not too unexpected, ocular com- over several days, the researchers that infl ammation is both the fort is of greater signifi cance in noted. There was little release cause and effect of DED,” explains non-presbyopic lens wearers, while of IL-4 from a coated lens in the Dr. Shovlin. “Diet infl uences vision satisfaction is of greater sig- absence of enzymes, indicating the many aspects of health, including nifi cance in the presbyopic group.” coating was degraded primarily University of by enzymatic means, the study Photo: Scott G. Hauswirth, OD Pittsburgh researchers noted. “Our results support the developed a cytokine hypothesis that our polymeric IL-4 coating for silicone releasing coating can be applied hydrogel lenses they to contact lenses with a resulting believe could provide sustained release of drug over days a sustained treat- vs. the transient burst release seen ment for dry eye. with eye drops,” the investigators Interleukin-4 (IL-4) has wrote in their abstract.14 been shown to polar- ize macrophages from TECH ADVANCEMENTS the infl ammatory M1 Treatments for corneal blind- phenotype—which is ness are limited by a high rate of prevalent in DED—to complications and may not be as the anti-infl ammatory effective in cases of severe ocular M2 phenotype. IL-4 surface damage. With this in mind, can be incorporated researchers invented an intraoc- A cytokine coating for soft lenses could provide into a nanometer-thick ular implant that projects light sustained dry eye treatment. coating to mitigate the directly onto the retina, bypassing

14 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 treras A, et al. Corneal crosslinking eff ects on tear the damaged cornea—an alterna- with currently available surgical infl ammatory mediators in patients with keratoconus. tive approach for treating corneal options,” Dr. Shovlin says. ARVO 2019. Abstract 336. 5. Seifert F, Seufert F, Hommes D, et al. Ten year opacity. The device captures light results after corneal collagen crosslinking with ribofl avin and UV-A irradiation (CXL) for keratoconus— via an external camera and then his remarkable body of re- when to repeat CXL? ARVO 2019. Abstract 339. wirelessly sends data to an intraoc- search continues to broaden 6. Safi S, Jafarinasab M, Feizi S, et al. A new topo- T graphic “quad signs” for diagnosis and grading of ular microdisplay.15 horizons for practitioners and pellucid marginal degeneration. ARVO 2019. Abstract 2104. They found that the intraocu- provide useful knowledge bene- 7. King-Smith P, Mauger T, Begley C, Tankam P. Does lar projector can restore vision in fi cial for the patients under their the peripheral light focusing eff ect explain the strong nasal location preference of pterygia? ARVO 2019. people blinded by corneal opacity, care. This is just a sampling of the Abstract 4701. 8. Gefen R, Segev F, Geff en N, et al. A new hy- possibly providing a more acces- fi ndings presented at ARVO— perspectral imaging method to evaluate dry eye sible solution to those who may the conference boasted so much disease—3D-WLT study results. ARVO 2019. Abstract 6780. not be ideal candidates for cornea more worth exploring. Check out 9. Messmer EM, Schaumberger MM, Proglinger S, Koenig SF. Evaluation of tear fi lm osmolarity using transplantation or keratoprosthe- ARVO’s full listing of abstracts to Tearlab and I-Pen osmometry. ARVO 2019. Abstract sis. The researchers successfully see for yourself the other latest ad- 6773. 10. Villani E, Marelli L, Lucentini S, et al. The Ocular constructed four functioning vances in disease pathophysiology, Surface Frailty Index as a predictor of dry eye onset implants (9.5mm x 7mm x 7mm). diagnosis and management. RCCL after cataract surgery. ARVO 2019. Abstract 6776. 11. Downie LE, Lee J-H, Makrai E, et al. A novel With a lens placed 4mm from approach to identifying dry eye disease using acous- 1. Sahebjada S, Chan E, McGuinness M, et al. Assess- tically-driven microfl uidic extensional rheometry. the microdisplay (focal length of ment of clinical parameters by ethnicity in patients ARVO 2019. Abstract 4189. 3mm), they found that the devices with keratoconus: a multi-country study. ARVO 2019. 12. He X, Zhao Z, Bu J, et al. High fat diet induced Abstract 321. functional and pathological changes in lacrimal produced a visual acuity of up to 2. Ling JJ, Mian S, Stein JD, et al. Impact of scleral gland. ARVO 2019. Abstract 1416. 20/127.15 contact lens use on risk of requiring corneal trans- 13. Diec J, Naduvilath TJ, Tilia D, Bakaraju RC. The plantation for keratoconus. ARVO 2019. Abstract relationship between vision and comfort in contact “This device appears to provide 4779. lens wear. ARVO 2019. Abstract 6366. 3. Kato N, Negishi K, Sakai C, et al. Five year out- 14. Jhanji V, Nolfi A, Kulkarni M, et al. Polyelectrolyte high levels of functional vision comes of corneal collagen crosslinking: accelerated multilayer coating for delivery of IL-4 from contact with few complications and should crosslinking induces less corneal haze and less con- lenses for dry eye disease. ARVO 2019. Abstract 262. tinuous corneal fl attening compared to conventional 15. Fan V, Rosenblatt M, Sun M, et al. Intraocular be a viable alternative for patients crosslinking. ARVO 2019. Abstract 313. microdisplay projection system for treating corneal who are at high risk for failure 4. Mendoza-Garcia DLT, Del Valle CP, Robles-Con- blindness. ARVO 2019. Abstract 4697.

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Administered by Review Education Group partners with Salus University for those ODs who are licensed in states that require EVIEW university credit. Visit www.reviewsce.com/events for any meeting changes or updates. EDUCATION GROUP *Approval pending — — — — — Getting Astigmatism — in Focus with — — Advanced Imaging — isual rehabilitation with The separation of the concen- measure such structures as the ep- — contact lenses for patients tric rings helps calculate inferred ithelial corneal thickness. The two who suffer from irregular corneal curvature. The closer the technologies are able to measure an- — Vcorneas was a hit or miss, rings are to each other, the steeper terior and posterior corneal surfaces and often frustrating, endeavor. the curvature is at that location. as well as a global area of corneal — These patients typically were told The cumulative analysis of cor- thickness. that the only option available to neal curvature data then creates a Corneo-scleral profi le analysis them was corneal gas permeable topography map. Curvature data is provides a detailed description of — contact lenses (GPs). an excellent way to infer the optical the anterior surfaces of the cornea For fi ttings, practitioners used characteristics of the visual system and the sclera (Figure 1). With — keratometry fi ndings as a start- since the majority of refraction the increased popularity of scleral ing point and followed up with takes place at the anterior ocular lenses, corneo-scleral profi ling is — diagnostic GPs and a fl uorescein surface interface. revolutionizing our understanding evaluation. With the advent of Evident in these subsequent case of anterior segment shape and our — today’s advanced technologies, we examples, one can analyze curva- ability to design lenses that con- are able to measure the shape of the ture data of the anterior cornea in tour, with great precision, a surface — cornea and the ocular surface with order to predict refractive perfor- that is now known to be quite high precision, thus providing a far mance. Still, there are some signif- asymmetric. — greater understanding of the disease icant limitations to information state and an improved direction to obtained from Placido-based cor- CASE 1: IS IT PMD? — better fi t our patients. neal topography that often hinder A 53-year-old woman was referred We can also now evaluate visual our understanding of the disease to our practice from a local op- — performance with and without con- state. These include, among others, tometrist for advanced contact lens tact lenses in ways that were only an inability to measure the poste- management based upon a suspect- — available in the optics laboratory rior cornea or the global corneal ed diagnosis of pellucid marginal in the past. This article highlights thickness. degeneration (PMD). The optome- — cases that have incorporated many trist found signifi cant against-the- of the available advanced ophthal- ANTERIOR SEGMENT OCT AND rule astigmatism and performed — mic technologies that have made CORNEO-SCLERAL PROFILING Placido-based corneal topography, great strides in clinical success and Tomography is a two-dimensional which reportedly found what has — effi ciency. representation of a three-dimen- been described as a “crab claw” or sional structure. Ocular tomogra- a “kissing dove” pattern. Physical PLACIDO-BASED phy provides imaging and analysis examination of the patient revealed — CORNEAL TOPOGRAPHY of multiple “slices” of the cornea This imaging technology uses infor- and anterior segment. Specifi cally, ABOUT THE AUTHOR — mation processed from concentric Scheimpfl ug tomography uses a Dr. Eiden is the president rings refl ected off of the anterior photographic imaging technology to and medical director of — ocular surface in order to calculate provide a 360° analysis. North Suburban Vision Consultants in Illinois corneal curvature. Since the refl ec- Anterior segment ocular coher- and the president — and cofounder of the tion is actually off of the tear layer, ence tomography (AS-OCT) can International Keratoconus its stability or instability will have also provide similar imaging with Academy. — a dramatic effect on the outcomes. even greater resolution in order to — — 16 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 — — — — — — Four cases provide insight into diagnosing and — managing patients with the latest options. — By S. Barry Eiden, OD — — no evidence of inferior thinning in the perilimbal zone of the cornea. — There was evidence of mild Vogt’s striae (grade 1) located inferiorly — and paracentrally along with a mild and partial inferior Fleischer’s ring. — No corneal scarring was found. Manifest refraction revealed a highly myopic astigmatic refractive error — (-5.00 -6.00x70) with a best-corrected visual acuity of 20/20-2. — In order to better understand the corneal condition, Scheimpfl ug- Fig 1. Corneo-scleral profi le software from Pentacam tomography system. — based corneal tomography was Image: Tom Arnold, OD performed using the Pentacam — (Oculus) instrument (Figure 2). Looking at the axial curvature — display fi rst revealed PMD’s classic crab claw/kissing dove pattern; — however, the elevation displays on the anterior and posterior cornea — were quite typical of keratoconus. More importantly, the global — pachymetry display showed that the thin point of the cornea was located — coincident with the apex of the cone Fig 2. The upper right axial or Fig 3. Global pachymetry display in an inferior paracentral position. curvature map of the anterior cornea from Pentacam with area in true PMD — In true PMD, the thinning of the shows the “crab claw” or “kissing shows the band of inferior peripheral cornea would be located inferiorly dove” pattern. corneal thinning. — in the far periphery of the cornea, manifest refraction. Contact lens ture data (derived from elevation corresponding to an area about one management then allowed my team measurements). Additionally, it — to two inches from the limbus. to consider using soft contact lens- is able to measure global corneal Another interesting observation es. In fact, we were able to fi t the thickness from limbus to limbus. in this case is the regularity of patient in a custom toric multifocal This technology allows the clinician — corneal curvature within the pu- contact lens (SpecialEyes near cen- access to comprehensive informa- pillary zone. Although six diopters ter progressive toric multifocal) and tion about the entire corneal struc- — of corneal astigmatism was mea- obtain 20/20 distance and 20/25 ture. Beyond corneal measurements, sured by Pentacam via “Sim Ks,” near visual acuity. Scheimpfl ug corneal tomography is — there was almost no irregularity Scheimpfl ug corneal tomography also able to image out to the scleral to the pattern. As such, it was no provides true elevation data from surface (providing corneo-scleral — great surprise that we were able to the anterior and posterior corneal profi le data) and posteriorly as well achieve very good visual acuity with surfaces as well as corneal curva- to provide information and data — — REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 177 — — — — — — GETTING ASTIGMATISM IN FOCUS WITH ADVANCED IMAGING regarding the anterior chamber, iris aberrometry has also been sug- grade 1 Vogt’s striae (no scaring) — and crystalline lens. gested as a means to differentiate OD and entirely normal OS. This case is an excellent example keratoconus from PMD. One study Manifest refraction found best — of the vast majority of instances assessed higher-order aberrations spectacle acuity OD at 20/30+ and where anterior corneal curvature and found greater amounts of verti- OS at 20/15. Scheimpfl ug corneal — maps show what was formerly cal coma in keratoconus and greater tomography (Pentacam) revealed thought to be PMD. From clinical amounts of trefoil in patients with OD a classic keratoconus pattern of — experience, the overwhelming ma- PMD.2 Another suggested that mild-moderate degree. The OS im- jority of cases with these curvature increases in coma-like aberrations age revealed an inferior steep zone — patterns have actually been true of the cornea refl ect the subclinical on anterior curvature but a normal keratoconus when we look at eleva- progression of PMD over the years.3 central area. Elevation maps found — tion and global pachymetry results a normal anterior elevation but an found from corneal tomography. CASES 2 & 3: IS IT abnormal posterior elevation along — One study described this phenome- UNILATERAL KERATOCONUS? with a borderline abnormal pro- non exquisitely.1 When true PMD is A 57-year-old female was referred gression of global corneal thickness — found, the clinician will see a band for contact lens management from from center to periphery (Figure 4). of inferior corneal thinning typi- an ophthalmology group based on a Abnormal posterior corneal shape cally located 1mm to 2mm in from /diagnosis of unilateral keratoconus and abnormal corneal thickness — the inferior limbus.1 In addition, if of the right eye. The referring doc- distribution or thickness progres- one expands the area displayed on tor performed no corneal imaging. sion are considered two of three — the global pachymetry map from a Diagnosis was based on biomicros- critical diagnostic fi ndings for typical 8mm or 9mm to 12mm in copy and manual keratometry in keratoconus.4 Aberrometry (Nidek — cases of true PMD, one will now see addition to a positive family history OPD-Scan III) measured visual the band of inferior thinning found of keratoconus. Biomicroscopy performance and found signifi cant — in this disease (Figure 3). Wavefront revealed Fleischer’s ring OD and elevation of high-order aberrations

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Fig 4. (a) Pentacam 4-Map Refractive Display OD with keratoconus patterns. (b) Pentacam Belin Ambrosio Ectasia — Display OD with strongly positive ectasia detection. (c) Topometric Display OD shows strong keratoconus staging and abnormal keratoconus indices derived from the anterior corneal surface. (d) Refractive Display OS with inferior axial — steepening, normal anterior elevation, mildly abnormal posterior elevation and what would appear to be normal corneal thickness. (e) Ectasia Display OS shows normal anterior elevation, abnormal posterior elevation and borderline corneal thickness distribution/progression with a statistically normal minimal corneal thickness reading. (f) Topometric display — OS shows normal keratoconus staging values and anterior corneal keratoconus indices. — — 18 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 — — — — — developing this pattern. In this case, although the Pentacam was — found to be signifi cantly abnormal OS and normal OD, there was a — noted asymmetric bilateral increase in epi-thickness variability found — with AS-OCT (Figure 7). Continued work in this area will tell us — whether this indication of bilateral keratoconus might be found earlier — in the course of the disease. With the advent of corneal cross- — linking and our ability to control keratoconus progression, early — detection of disease and of progres- Fig 5. (Top) Aberrometry OD shows elevation of high-order aberrations of total, sion have become critical in our — anterior corneal and internal. (Bottom) Aberrometry OS shows normal high- ability to preserve vision. Detection order aberration fi ndings of all three. of the disease and of its progression — (anterior corneal, internal and sequential Scheimpfl ug corneal to- are dependent on both our defi ni- total aberrations) OD; however, mography (Pentacam), there was no tion of the disease and available OS had normal levels of high order demonstrable progression in the left diagnostic technologies. — aberrations, thus corroborating the eye and no development of clinical- Decades ago, classic biomicro- excellent vision quality found with ly detectable keratoconus in the left scopic fi ndings, scissors refl ex with — manifest refraction (Figure 5). eye over this period of time (Figure retinoscopy and distorted manual Aberrometry detects high-or- 6). However, performance of AS- keratometry detected keratoconus. — der aberrations that are found in OCT allowed us to measure corneal In fact, reports on the prevalence of keratoconus and can be present epithelial thickness and produce an keratoconus based on these diag- — even in the presence of 20/20 visual epithelial thickness map. nostic criteria likely have dramati- acuity. As such, aberrometry has Variability of epithelial thick- cally underestimated how common — been shown to be infl uenced by ness across the cornea has been the condition actually is.6 With early keratoconus as long as there shown to be signifi cantly greater in the introduction of Placido-based — is some shape anomaly of either the keratoconus compared with normal corneal topography, eye care prac- anterior or posterior cornea within corneas.5 A typical pattern often titioners began to detect keratoco- — the pupillary zone. In this case, develops where there is epithelial nus at earlier stages where former corneal shape OS was entirely nor- thinning over the cone apex with diagnostic criteria were absent. — mal within the pupillary zone. The a surrounding “donut” of epithe- Subsequent studies of keratoconus patient was subsequently successful- lial thickening, but epi-thickness prevalence that included topograph- — ly fi t into corneal GP lenses with a variability will show, earlier in the ic fi ndings resulted in signifi cantly posterior aspheric shape to provide disease, an increase even before higher rates.7 — presbyopic correction. Though it may be considered normal, the left — eye surely suggests that the condition is bilaterally asymmetric. Based — on the patient’s age, there was a relatively low risk for progression, but annual monitoring of tomogra- — phy has been performed. A 42-year-old male was examined — who had also been diagnosed and managed with what was thought to — be unilateral keratoconus of the left Fig 6. (Left) Pentacam OS 4-Map Refractivet Display shows classic keratoconic eye for a number of years. Based on patterns. (Right) Ectasia Display OS showsw strongly positive ectasia detection. — — REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 199 — — — — — — GETTING ASTIGMATISM IN FOCUS WITH ADVANCED IMAGING — — — — — —

— Fig 7. Pachymetry Display. (Left) OS shows abnormal global corneal thickness and a classic pattern of thinning of the epithelium over the cone apex and surrounding epithelial thickening. (Right) OD shows normal global corneal thickness — but abnormal epithelial thickness distribution. Today we are developing di- corneal elevation asymmetry but no noticed progressive discomfort and — agnostic technologies, such as evidence of ectasia. Mapping of the reduced wearing time. Ultimately, Scheimpfl ug corneal tomography, global pachymetry and epithelial the patient was referred to our AS-OCT with epithelial thickness thickness found signifi cant epithelial practice for consideration of im- — mapping and clinically applicable thickness variation but no evidence pression scleral prosthetic treatment aberrometry, that further push of post-surgical ectasia. Specular (EyePrintPro). The impression was — the boundaries of early detection. microscopy revealed a reduced cell scanned using a 3D printing scanner Beyond this, efforts are being made count and cellular morphological that created a detailed corneo-scler- — in corneal biomechanics and genetic anomalies of size and shape; howev- al 3D model, from which an initial screening to identify patients with er, the cell count was over 1,000. As prosthetic device was designed — pre-clinical keratoconus and those such, concerns for fi tting a scleral (Figure 9). at high risk for its development.8,9 lens in terms of oxygen transmissi- At follow-up after initial dis- — bility existed but did not absolutely pensing, biomicroscopy discovered CASE 4: OUT TO THE contraindicate scleral lens wear areas of inferior/inferior-temporal — CONJUNCTIVA (Figure 8). conjunctival injection. The patient A 64-year-old Caucasian male was The patient was fi t in multiple reported progressive lens awareness — referred by a cornea group and their traditional scleral designs but had in the associated areas as wearing affi liated optometrist to manage a — case of scleral lens intolerance of the right eye. The patient had a history — of bilateral radial keratotomy (RK). He initially had good vision for — over 20 years but gradually noticed that his right eye vision had become — progressively blurry and distorted with increased glare and light sensi- — tivity. The patient had a secondary LASIK procedure and developed what he said was a post-operative — “infection” that resulted in progressive visual distortion. Subsequently, — he developed bilateral cataract and had surgery. — Fig. 8. Post-RK/LASIK. (Left) Pentacam 4-Map Refractive Display shows non- Scheimpfl ug tomography showed orthogonal irregular astigmatism within the pupillary zone and signifi cant non-orthogonal irregular astig- anterior elevation asymmetry. (Right) OCT pachymetry map shows signifi cant — matism and signifi cant anterior irregularity of the epithelial thickness but no evidence of ectasia. — — 20 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 — — — — — most irregular ocular surfaces. That being said, conditions of the ocular — surface, such as conjunctivochalasis, can continue to challenge ocular — comfort and lens fi tting success.11 In certain cases, surgical intervention is — the best option to address the issues of chalasis and to allow patients to — return to comfortable and effective contact lens wear.12 — Fig 9. (Left) A 3D printed model from an initial EyePrint impression is used to design the customized prosthetic. (Right) This corneo-scleral profi le map is also dvancements in imaging tech- — constructed from the 3D printed impression. Anologies have signifi cantly improved our ability to both diagnose — and manage corneal and other anterior segment diseases. Investing in — such technologies provides a return of investment that goes far beyond — the fi nancial accounting—it results in better care for our patients. RCCL — 1. Belin MW, Asota IM, Ambrosio R Jr, Khachiki- an SS. What’s in a name, keratoconus, pellucid marginal degeneration and related thinning — disorders. Am J Ophthalmol. 2011;152(2):157-62. 2. Pepose J. Wavefront aberrations in patients with keratoconus and pellucid margin- — al degeneration. Invest Ophthalmol Vis Sci. 2004;45(13):2893. 3. Kamiya K, Hirohara Y, Mihashi T, et al. Pro- — gression of pellucid marginal degeneration and Fig 10. (Top) Post-RK/LASIK OCT with EyePrint prosthetic device in place higher-order wavefront aberration of the cornea. shows impingement of the inferior conjunctiva due to conjunctival redundancy Jpn J Ophthalmol. 2003;47(5):523-5. — and chalasis. (Bottom) Same area following chalasis surgery without loose 4. Gomes JA, Rapuano CJ, Belin MW, Ambrósio conjunctival entrapment. R Jr; Group of Panelists for the Global Delphi Panel of Keratoconus and Ectatic Diseases. — Global consensus on keratoconus and ectatic time increased. Careful observa- surface shape and have led to the diseases. Cornea. 2015;34(4):359-69. tion noted inferior and temporal development of advanced scleral 5. Kanellopoulos A, Asimellis G. OCT corneal — epithelial topographic asymmetry as a sensitive conjunctivochalasis and inferior/ lens designs that better contour to diagnostic tool for early and advancing kerato- inferior temporal entrapment of the entire anterior ocular surface.10 conus. Clin Ophthalmol. 2014;8:2277-87. — 6. Kennedy RH, Bourne WM, Dyer JA. A 48-year redundant conjunctiva under the New instruments, such as the Eaglet clinical and epidemiologic study of keratoconus. lens edge (Figure 10). Numerous at- Eye Surface Profi ler (Eaglet Eye) Am J Ophthalmol. 1986;101(3):267-73. — tempts at design modifi cation failed and the sMap 3D (Precision Ocular 7. Godefrooij DA, de Wit GA, Uiterwaal CS, et al. Age-specifi c incidence and prevalence of to resolve the problem. A referral Metrology), and software devel- keratoconus: a nationwide registration study. Am — was made to our oculoplastic sur- opments like the CSP Pentacam J Ophthalmol. 2017;175:169-72. 8. Bao F, Geraghty B, Wang Q, Elsheikh A. Role geon, who performed conjunctival software bring the measurement of of corneal biomechanics in the diagnosis and management of keratoconus. In: Alió J, ed. Kera- — patch removal with amniotic graft corneal and scleral shape into the toconus: recent advances in diagnosis and treat- to address the chalasis. Following hands of eye care professionals. ment. Cham, Switzerland:Springer;2017;141-50. — healing, reapplying the EyePrint de- The ability to take an ocular 9. Bykhovskaya Y, Margines B2, Rabinowitz YS. Genetics in Keratoconus: where are we? Eye Vis vice provided signifi cantly improved surface impression, as is possible (Lond). 2016;3:16. comfort and vision. with the EyePrint system (EyePrint 10. van der Worp E. A Guide to Scleral Lens — Fitting, Version 2.0 [monograph online]. Forest Corneo-scleral profi le measure- Prosthetics) expands the ability Grove, OR: Pacifi c University; 2015. commons. ments are now becoming clinically to create a detailed model with pacifi cu.edu/mono/10. Accessed March 17, 2019. — 11. Meller D, Tseng SC. Conjunctivochalasis: liter- available to anterior segment and precision that is unmatched. With ature review and possible pathophysiology. Surv contact lens professionals. These these tools, we can now develop Ophthalmol. 1998;43(3):225-32. — 12. Marmalidou A, Kheirkhah A, Dana R. Conjunc- measurements have shed light scleral lenses and scleral prosthetic tivochalasis: a systematic review. Surv Ophthal- on the complexity of the scleral devices that can contour even the mol. 2018;63(4):554-64. — — REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 211 — — Fitting the Irregular Cornea: NUTS AND BOLTS Here’s a beginner’s guide to help you get started.

By Lindsay A. Sicks, OD

nce you realize you are aniseikonia or both with spectacles, the patient currently wears spec- dealing with an irregu- as this will bolster your case for tacles or contact lenses), a pinhole lar cornea, how do you prescribing medically necessary acuity, if indicated, and uncorrected Ofeel? Scared? Excited? correction with contact lenses. visual acuity (usually taken after Nervous? Perhaps all of the above? Ocular dryness history should any entering lenses are assessed). If you’re an eye care practitioner also be explored, preferably with a Following a fresh manifest refrac- who is energized by the challenge of validated questionnaire that can be tion, you will have another measure improving vision for patients who repeated at subsequent offi ce visits of best-corrected spectacle acuity. cannot see well with spectacles, to evaluate any changes in signs and Contact lens patients should have then you might already be famil- symptoms over time. a pair of backup spectacles in case iar with some of the lenses in our A quick inquiry into the patient’s they ever fi nd themselves in a situ- arsenal. vocation and hobbies can automat- ation where they cannot wear their On the other hand, if you are a ically steer your evaluation toward lenses, especially so they do not feel little more hesitant or are looking certain lens designs. For example, tempted to over-wear them. to expand your options for irregu- a truck driver may require a gas Patients will often express a lar cornea patients, here is a primer permeable (GP) lens for best acuity desire for a backup pair of specta- on the examination information while driving. A retired patient, cles if given the option, even if their you should be gathering and the though, may desire a part-time vision is not as crisp as it is with lens options worth considering. wear option where acuity may their contact lenses. If the patient not be as crucial for a successful has a high amount of anisometro- EXAM DATA outcome. pia in their manifest refraction, it Examining any patient with an ir- A critical look at a patient’s dex- might be useful to trial frame the regular cornea starts with obtaining terity, hygiene and potential for lens result obtained and cut the sphere, an extensive case history. While it’s handling limitations can help you cylinder powers or both down until important to understand a patient’s determine whether to include or you achieve the best balance of current complaints in detail, it also exclude certain lens modalities from tolerable anisometropia and best benefi ts us to know their past ocu- the start or recommend additional visual acuity. lar surgical procedures and contact assistance. For example, an elderly Other entering data to consider lens wear history. patient with rheumatoid arthritis when choosing a contact lens mo- With regards to a patient’s may not be able to manipulate their dality include: pupil size, horizontal complaints, assessing their level of fi ngers to apply and remove a lens blur, halos, glare, fl are and diffi cul- as easily. A patient with a tremor ABOUT THE AUTHOR ties with night vision can uncover may not be able to steady their telling information. hands long enough to handle a lens. Dr. Sicks is an assistant Using tomographic or topograph- To help, assistive devices exist that professor at the Illinois College of Optometry ic maps can assist in evaluating the can come in handy when patient and serves as a clinical attending in the Cornea tear fi lm and the cornea’s front and handling on insertion or removal Center for Clinical back surface characteristics. presents a challenge. Excellence at the Illinois Eye Institute. She lectures After a careful manifest refrac- Your initial physical examina- and participates in research tion, consider whether the patient tion of a patient should include on specialty contact lenses. is experiencing any anisometropia, measuring best-corrected acuity (if

22 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 visible iris diameter, vertical lens set in your offi ce. This fi ssure width, corneal status is an easy and straight- (e.g., ectasia, scarring, trans- forward fi x for a patient’s plant status, sutures, dystro- reduced vision. These lenses phy, ocular surface disease, have planned short-interval endothelial cell count), replacement schedules and, lens status (e.g., cataract, if lost, ripped or torn, can intraocular lens, aphakic), easily be switched out for a conjunctival abnormalities new lens. (e.g., pinguecula, pterygium, If a patient needs powers conjunctivochalasis) and lid outside the available param- abnormalities (e.g., ptosis, eters, or if the patient has a dermatochalasis, rosacea, larger or smaller horizontal meibomian gland dysfunc- visible iris diameter than av- tion). Pay careful attention erage, a custom soft design to the best-corrected visual may be indicated. acuity and any comor- This 61-year-old Eastern European male presented Many custom soft lens bidities, such as retinal with a chemical burn in his right eye after an industrial designs are available in abnormalities, glaucoma accident. The patient was only able to achieve a quarterly replacement or previous ocular surger- fl uctuating 20/50 acuity with a corneal GP lens and was schedules, and some are experiencing diffi culty with adaptation because he only ies (e.g., glaucoma bleb wore the lens in one eye. Today, he sees 20/25 out of a available on a monthly or tube), which can also scleral lens in the right eye. replacement basis. These fi ts inform the fi tting process are straightforward, and key moving forward. When fi tting these patients, consid- characteristics include lens cov- If ocular surface disease is preser if the visual benefi t of a scleral erage, centration and movement. ent, treating it prior to commenc- lens is worth the risk of decompen- Timely follow-up visits can confi rm ing lens wear is a must; however, sation or if a lens with a smaller the lenses are being used properly patients with severe ocular surface diameter, greater tear exchange and and the fi t is not causing any harm disease, especially in the presence better oxygen transmission would to the eye. of other irregular corneal fi ndings, be more benefi cial. In lenses with quarterly or longer often benefi t from scleral lens wear Further analyzing the endothelial replacement cycles, a hydrogen per- to help treat and manage their cell count scan can also help predict oxide-based solution may provide condition.1,2 the risk associated with a scleral better deposit resistance and a more For patients with a history of lens; specifi cally, a coeffi cient of comfortable, preservative-free lens corneal transplant, obtaining a variation <30% and a hexagonality wearing experience. baseline endothelial cell count and a value >50% bode well for fi tting If the vision achieved with stan- pachymetry value is recommended success.7 dard soft contact lens designs is not prior to lens fi tting. This will allow Pachymetry measurements also acceptable, it may be because the you to monitor the health of the assist with assessing endothelial cell corneal irregularity is too great. In graft in the presence of the lens, function. An increase in pachymetry this case, a specialty lens design for modify the lens or lens wearing of more than 20µm to 40µm after the irregular cornea may be neces- schedule or refer the patient for fur- scleral lens removal is concern- sary. Designs of this type are avail- ther surgical intervention if indicating.7,8 Post-keratoplasty patients able for both prolate ectasias and ed based on changes in the health of fi t with scleral lenses require close oblate post-surgical corneal profi les. the transplant.3,4 follow-up to monitor for signs of They generally correct vision in one Corneas with endothelial cell hypoxia and rejection or failure. of two ways, either by increasing densities below 1000cells/mm2 are center thickness to mask irregular at an increased risk for swelling and LENS OPTIONS astigmatism or by using aspheric decompensation.5 Chronic endothe- Sometimes the contact lens solution designs to limit aberrations. lial decompensation occurs when for an irregular cornea is as simple The lenses can have center thick- endothelial cell density is between as a soft sphere or toric lens that ness values ranging from 0.4mm 400cells/mm2 to 700cells/mm2.5,6 you likely already have in a trial to 0.6mm to accommodate corneal

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 23 FITTING THE IRREGULAR CORNEA: NUTS AND BOLTS Photo: John Gelles, OD irregularity, although newer continue on your way. “thin” designs are closer to Piggybacking a GP lens on 0.2mm in thickness. These thin top of a soft lens is also an op- designs can even out tear distri- tion but is sometimes forgotten bution underneath the soft lens by fi tters. Soft contact lenses with better draping to improve can cushion the cornea and peripheral fi t and are more ideal improve GP lens stability, cen- for low cone, pellucid, post- tration or both. A piggyback graft and post-surgical cases can also be a bridge that keeps due to their increased oxygen a patient in a more cost-effec- transmissibility.9 tive corneal GP lens design and Various irregular cornea soft prevents them from having to lens designs may also incorpo- transition to hybrid or scleral rate toricity to help with any re- lenses. sidual astigmatism present in the Practitioners should inde- over-refraction. These lenses are pendently assess the fi t of each available in traditional hydrogel lens (soft and GP) for move- materials and latheable silicone ment and keep in mind that the hydrogel material to increase soft contact lens clinically only oxygen transmissibility and contributes about 20% of its reduce the risk of hypoxia and power to the system.11,12 neovascularization. They are Fitters should also be atten- great options for mild to moder- tive to the overall oxygen trans- ate irregularity and for patients missibility of the lens system. hesitant to try a GP lens.10 Fluorescein pattern of a scleral lens on an eye For optimal oxygen transmissi- It is important to set visual with keratoconus. bility, silicone hydrogel soft lens acuity expectations with patients designs are preferred. It may be prior to trying these designs, as way to achieve optimal visual cumbersome, however, for patients acuity may not be as good as that acuity. Indeed, in patients with a to have to handle and care for two achieved with corneal GP designs post-transplant eye, it may also be lenses per eye instead of one. This (although sometimes it is just as the most physiologically favorable can be streamlined somewhat with good, if not better). design if fi t properly to facilitate the recommendation of a hydrogen In the offi ce, perform a careful good tear exchange and oxygen peroxide-based care system and one over-refraction and pay attention to transmissibility. case for each set of lenses or a daily lens cylinder axis and any rotation If you’re fi tting a specialty GP disposable silicone hydrogel soft that may be present on the diag- lens design for the irregular cornea, lens option. nostic lens to ensure the best visual the steep keratometry reading is Hybrid contact lenses have a GP outcome. Some specialty soft lens often a good starting point; howev- lens center surrounded by a soft designs are fi t with the assistance of er, the best strategy is to follow the lens skirt. These designs provide ex- sodium fl uorescein that has a high manufacturer’s fi tting guide and use cellent visual acuity due to the GP molecular weight; however, with the sodium fl uorescein pattern and center and ensure patient comfort is the current diffi culty in sourcing over-refraction to guide the fi tting maintained as the soft lens interacts such fl uorescein, make sure you process. with the eyelid. These lenses also return to the laboratory’s specifi c Many designs have unique provide excellent on-eye lens cen- fi tting guide for the particular lens characteristics that allow you to tration and can be purchased with you’re working with, as some of independently fl atten or steepen add-on coating to enhance lens wet- the lens fi tting characteristics and different areas of the lens to achieve tability and comfort. They generally troubleshooting options are unique the optimal fi t. Acquiring slit lamp require less lens vault than a scleral to each design. photos, videos or both and calling lens and, therefore, can provide In patients with corneal irregular- a laboratory consultant can also enhanced oxygen transmissibility ity, a corneal GP lens design is often help alleviate potential doubts and when fi t properly with acceptable the easiest and most cost-effective answer questions so that you can movement on blink. Hybrid lenses

24 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 ing tear layer lar cornea than ever before. more convex. As specialty lens fi tting grows Switching to in popularity, we not only see an oblate lens life-changing improvements in vi- design can sual function in our patients but we help reduce also see industry growth fueling fur- lens power and ther innovation and development. improve vision When you’re ready to take the by reducing plunge, just remember the variety distortion. of lenses you have at your dis- Other fi tting posal. While the fi rst lens you try challenges, such might not be the perfect fi t, you as conjunctival can achieve success (and avoid prolapse, epi- complications) with persistence, thelial bogging, motivation, trial and error and A 32-year-old Hispanic male with pellucid marginal midday fogging the guidance of expert laboratory degeneration and an elevated pinguecula in each eye and limbal consultants. RCCL presented complaining of visual distortion with his bearing, are spectacles. He had discontinued GP lens use due to 1. Schornack MM, Pyle J, Patel SV. Scleral lenses in discomfort issues and challenges that arose from using the unique to scler- the management of ocular surface disease. Oph- thalmology. 2014;121(7):1398-405. lenses at his job. Despite achieving 20/25 acuity in a scleral al lens wear 2. Shorter E, Harthan J, Nau CB, et al. Scleral lens with a toric periphery (to avoid compression on the and should also lenses in the management of corneal irregularity pinguecula), the patient decided he would rather wear a be addressed and ocular surface disease. Eye Contact Lens. specialty soft lens that gave him 20/30 acuity. 2018;44(6):372-8. if they arise 3. Jackson AJ, Robinson FO, Frazer DG, et al. Cor- 14 neal guttata: a comparative clinical and specular may even allow for more rapid tear during the fi tting process. micrographic study. Eye (Lond). 1999;13(6):737-43. exchange than scleral lenses.13 In patients for whom even a high- 4. Palay DA, Kangas TA, Stulting RD, et al. The eff ects of donor age on the outcome of pene- Modern scleral lenses have ly customized scleral lens cannot trating keratoplasty in adults. Ophthalmology. rapidly risen in popularity over the achieve the best vision or physiol- 1997;104(10):1576-9. 5. Lass JH, Sugar A, Benetz BA, et al. Endothelial last decade, and their availability ogy, a custom-molded, optically cell density to predict endothelial graft failure after penetrating keratoplasty. Arch Ophthalmol. in high Dk GP materials has fueled clear prosthetic scleral device may 2010;128(1):63-9. their use in irregular and regular be indicated. Only once a practi- 6. Melles G, Lander F, Rietveld F, et al. A new surgical technique for deep stromal, anterior lamellar cornea applications. tioner completes the comprehensive keratoplasty. Br J Ophthalmol. 1999;83(3):327-33. These lenses are large enough certifi cation process for these lenses 7. Sindt CW. Endothelial cell density: when it becomes a contraindication? AiLES Conference: to tuck under lids and range in are they able to fi t patients in their scleral lens 2.0: from the past, the lens of the size from approximately 13mm offi ce.15 future. Rome. June 11, 2018. 8. Barnett M, Johns LK. Contemporary Scleral to 22mm, providing exceptional Impression material is applied Lenses: Theory and Application. Vol. 4. Bentham comfort for the patient. The addi- to the eye with a specialized tray Science Publishers, 2017. 9. Kerasoft Thin. www.kerasoftlens.com/profession- tion of toric- or quadrant-specifi c device to create an impression mold al/why-choose-thin/. Accessed March 11, 2019. peripheral curves can help ensure of the cornea and sclera. This mold 10. Saraç Ö, Kars ME, Temel B, et al. Clinical evaluation of diff erent types of contact lenses in lens stability. Along with this sta- is then sent to the laboratory, which keratoconus management. Cont Lens Anterior Eye. February 23, 2019. bility comes the ability to include uses laser-imaging technology to 11. Woo M, Weissman BA. Eff ective optics of pig- advanced applications, such as create a contact lens that matches gyback soft contact lenses. Cont Lens Spectrum. 2011. multifocal and front toric optics or the impression. These lenses include 12. Michaud L, Brazeau D, Corbeil ME, et al. Con- edge lift options to vault conjuncti- highly customized options, such as tribution of soft lenses of various powers to the optics of a piggy-back system on regular corneas. val irregularities. prism, multifocal optics, decentered Cont Lens Anterior Eye. 2013;36(6):318-23. When fi tting the highly irregular optics and higher-order aberration 13. Achenbach P, Bergmanson J, Miller W, et al. Tear exchange beneath a vaulted hybrid contact lens. cornea with a scleral lens, limited correction.16 Cont Lens Anterior Eye. 2018;41(1):S39-40. 14. Walker MK, Bergmanson JP, Miller WL, et al. tear exchange, asymmetric vault Complications and fi tting challenges associated over a highly irregular surface ver the years, practitioners with scleral contact lenses: a review. Cont Lens Anterior Eye. 2016;39(2):88-96. and centration are still concerns. Ohave found new ways to 15. Eyeprint Prosthetics. www.eyeprintpro.com/. Additionally, vision can be com- restore visual function to patients Accessed March 11, 2019. 16. Eyeprint Prosthetics. Case reports. www. promised as the lens base curve in need. As of 2019, there are more eyeprintpro.com/case-reports/. Accessed March becomes steeper and the underly- contact lens options for the irregu- 11, 2019.

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 25 11th Annual OPTOMETRIC GLAUCOMA SYMPOSIUM Join our faculty of renowned ODs and MDs for a highly interactive meeting covering the most up-to-date information in glaucoma care. Earn up to 12 CE credits* for only $275.

EAST COAST October 4, 2019 - October 5, 2019 Renaissance Baltimore Harborplace Hotel 202 East Pratt Street Baltimore, MD 21202 Phone: 410-547-1200 Discounted room rate: $169 Please book with the hotel directly at 800-228-9290. Identify yourself as a participant of ECOGS for group rate. Rooms are limited. THREE WAYS TO REGISTER ONLINE: www.reviewsce.com/ECOGS2019 CALL: 877-451-6514 EMAIL: [email protected]

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Review Education Group partners with Salus University for those ODs who are licensed in states that require university credit. Up to 12 CE Credits*

PROGRAM CO-CHAIRS

Murray Fingeret, OD, FAAO Robert N. Weinreb, MD Chief of the Optometry Section, Chairman & Distinguished Professor of Ophthalmology Brooklyn/St. Albans Campus, Director of the Shiley Eye Institute Department of Veterans Administration Director of the Hamilton Glaucoma Center New York Harbor Health Care System Morris Gleich, M.D. Chair in Glaucoma Clinical Professor, University of California San Diego SUNY, College of Optometry

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*Approval pending See event website for complete details. for Keratoconus Improve Contact Lens Success? DOES CXL A review of the literature shows scant evidence for this eff ect. By Brian Chou, OD, and John Gelles, OD

orneal cross- Researchers evaluated linking (CXL) 20 eyes of 14 patients has gained with keratoconus who Cwidespread underwent CXL and re- clinical acceptance since ported improved rigid gas April 2016 when the FDA permeable (RGP) fi tting approved the Avedro KXL relationships and sub- system, which slows or jective patient comfort.7 halts progressive kera- Among their fi ndings, toconus. Today, CXL is they note that all patients the standard of care for reported acceptable fi ts, progressive keratoconus, with 20% experiencing an and many medical insur- increase in near-ideal fi t 1 ances cover the procedure. This patient is undergoing CXL. and 65% an improvement However, most keratoco- in subjective comfort with nus patients still require specialty restoration following the surgery.3,4 an eight-hour-longer duration of contact lenses for the best visual CXL temporarily reduces corneal comfortable contact lens wear.7 results post-CXL. Recently, there sensitivity for about six months, While subjectivity exists with what has been talk that CXL may make after which point sensitivity levels constitutes an improved RGP it easier to prescribe contact lenses return to their preoperative levels.5 fi tting relationship, the observed for keratoconus. In a study using confocal micros- improvement in subjective pa- Although the primary goal copy, we can see that the sub-basal tient comfort could be due to the of CXL is disease stability, the nerve plexus was not visible in relative hypoesthesia of the cornea procedure can also reduce corneal 90% of patients at one month following CXL. curvature and surface irregularity. postoperative but that corneal A review paper on CXL recently According to data submitted to the innervation nearly restored to mentioned an unpublished study FDA, the maximum keratometry preoperative levels by six months.5 reporting on contact lens tolerance value in the CXL treatment group These results corroborate the decreased by 1.6D from baseline fi ndings of an earlier study inves- ABOUT THE AUTHORS to one year.2 With a fl atter cor- tigating accelerated CXL, which Dr. Chou owns ReVision nea after the procedure, it seems also found that the sub-basal nerve Optometry, a referral intuitive that contact lens prac- fi ber density was reduced follow- center for treating 6 keratoconus and titioners would fi nd it easier to ing CXL. However, it notes that prescribing scleral prescribe contact lenses. Is there the density measurements did not contact lenses in San Diego, CA. peer-reviewed literature to support reach preoperative values until 12 this claim, though? Here, we take a months post-op.6 Dr. Gelles is the director closer look. From this literature, we can con- of the specialty contact clude that it is likely that the re- lens division at the Cornea and Laser Eye CXL AND LENS TOLERANCE duced corneal sensation after CXL Institute (CLEI) and the CLEI Center for General descriptions of contact enhances contact lens tolerance Keratoconus in Teaneck, lens prescribing after CXL un- during the fi rst six months after the NJ. derscore the importance of visual procedure.

28 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 in a small prospective randomized In the latter study, there is no time and attention appointed to clinical trial of 10 subjects (eight control for the lens design prior to lens haptic to scleral alignment keratoconus, two ectasia) who CXL. These patients could have rather than corneal alignment, it underwent CXL.8 Participants were preoperatively worn a poorly fi t seems unlikely that CXL would prescribed a hybrid contact lens RGP lens and postoperatively been impact scleral lens prescribing. three months post-op.8 Prior to prescribed a well fi t hybrid lens However, a recent case study used CXL, 62.5% of the keratoconus and experienced improvement a profi lometer—an ocular surface patients (5/8) claimed partial or simply due to changes in the lens topographer—to show that CXL good lens tolerance, whereas 90% type or fi tting relationship, not for keratoconus altered the scleral of all patients (9/10) reported satis- CXL. Overall, the sample sizes in shape.9 Keep in mind that this is factory lens tolerance at the conclu- both studies are too small to draw simply one case that raises more sion of the study.8 The authors state a reliable, accurate conclusion. questions about the global ocular that, despite the limited sample size shape effects of CXL. and the singular lens design, these CXL AND LENS PRESCRIBING fi ndings might show early evidence To be clear, asking whether CXL LINKING IT TOGETHER of improved contact lens tolerance makes it is easier to prescribe con- The claim that CXL makes it easier in post-CXL patients.8 tact lenses is different from asking for a clinician to prescribe contact Upon looking closer at the whether CXL increases patient lenses appears unfounded, at least previous two studies, several things contact lens tolerance. We are for the time being. This isn’t to are evident. The practitioner’s skill currently lacking published data overshadow the fact that CXL may level may contribute to improved assessing the ease of prescribing improve contact lens tolerance, fi tting relationships, patient com- contact lenses after CXL. In future possibly by causing short-term cor- fort and lens tolerance. It is unclear studies, contact lens practitioners neal hypoesthesia. Until compelling in either study if the same practi- could be surveyed on the average evidence comes forth to suggest tioner prescribed contact lenses to chair time and number of visits re- otherwise, the primary rationale the participants before and after quired to obtain a fi nal contact lens for undergoing CXL should be to CXL. If the patients’ original lenses Rx. Until then, however, we cannot stabilize disease progression. RCCL were prescribed by a less-experi- defi nitively answer this question. 1. Avedro. Is cross-linking covered by insurance? www. enced practitioner who handed the Despite scleral contact lenses— livingwithkeratoconus.com/is-cross-linking-right-for- reins off to a more skilled prac- which completely vault the cornea me/is-cross-linking-covered-by-insurance/. Accessed March 13, 2019. titioner after CXL, it would not surface—growing in popularity, it 2. Hersh PS, Stulting RD, Muller D, et al. United States multicenter clinical trial of corneal collagen cross- be surprising to fi nd better fi tting is unknown whether CXL enhanc- linking for keratoconus treatment. Ophthalmology. relationships and lens satisfaction. es their tolerability. With more 2017;124(9):1259-70. 3. Severinsky B. Contact lens use after corneal crosslinking. RCCL. 2016;153(5):28-32. 4. Michaud L, Breton L. Contact lens fi tting post-corneal cross-linking. Contact Lens Spectrum. 2018. 5. Ünlü M, Yüksel E, Bilgihan K. Eff ect of corneal cross-linking on contact lens tolerance in keratoconus. Clin Exp Optom. 2017;100(4):369-74. 6. Ozgurhan EB, Celik U, Bozhurt E, et al. Evaluation of subbasal nerve morphology and corneal sensation after accelerated corneal collagen cross-linking treatment on keratoconus. Curr Eye Res. 2015;40(5):484-9. 7. Singh K, Bhattacharyya M, Arora R, et al. Alterations in contact lens fi tting parameters following cross-linking in keratoconus patients of Indian ethnicity. Int Ophthalmol. 2018;38(4):1521-30. The left map was taken six months post-op, the center map was taken pre-op 8. Chang CY, Hersh PS. Corneal collagen cross-linking: a review of 1-year outcomes. Eye Contact Lens. and the right map is the diff erence or subtractive map showing 2.5D of Kmax 2014;40(6):345-52. fl attening. Note the superior steepening and the inferior fl attening over the 9. DeNaeyer G, Sanders D. Collagen crosslinking for cone, which represents normalization of the corneal shape. This patient had a keratoconus can change scleral shape. J Cont Lens robust response to CXL. Res Sci. 2018;2(1):e15-21.

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 29 1 CE Credit (COPE APPROVED)

Pathologic Causes of Irregular Astigmatism Thin is in—but not in the cornea. Here’s a rundown of non-infl ammatory corneal thinning disorders that lead to irregular astigmatism. By Thomas Stokkermans, OD, PhD Photo: Jonathan Lass, MD hen a refraction REFRACTIVE ERRORS doesn’t produce vi- Refractive errors at birth are vari- sual acuity of 20/20 able, decreasing until age six, when Wor leaves the patient the highest degree of emmetropia is with glare and ghosting, and your present.2,3 This applies to astigma- subsequent slit-lamp exam doesn’t tism as well. The average amount indicate an overt cause, irregular of astigmatism at birth is 3D and is astigmatism should be at the top of reduced to just 1D by age fi ve. your differential diagnosis list. However, not all children have a In these cases, corneal topography, reduction in their refractive errors, as pachymetry, retinoscopy with careful patients with high amounts of with- observation of the refl ex, a rigid the-rule or low amounts of against- gas permeable contact lens over-re- the-rule astigmatism will likely have fraction, wavefront aberrometry or signifi cant residual astigmatism later anterior segment optical coherence in life.2,3 This applies to anisometro- tomography (AS-OCT) can all help pia as well—while it is common to Keratoconus is associated with you identify irregular astigmatism as have some degree of anisometropia central corneal thinning resulting in the culprit. during the fi rst few years of life, corneal ectasia. While the crystalline lens may be children with higher amounts of increases the odds almost eightfold.4 one source of the problem, irregular anisometropia at a young age are As such, concern for corneal thin- astigmatism is more often caused by more likely to have it throughout ning is greatest in rapidly increasing the cornea. Of the corneal etiologies, their life.2,3 youth onset myopia or early-adult keratoconus is the most common Non-pathologic myopic pro- onset myopia for children with par- cause of primary irregular astigma- gression can be divided into four ents with myopia.5 tism (i.e., not caused by extraneous categories: congenital (present at causes such as surgery or contact birth, generally no emmetropization ABOUT THE AUTHOR lens wear) (Table 1).1 occurs), youth onset (occurs between Dr. Stokkermans is an To know when high amounts six years and early teens), early-adult assistant professor at of astigmatism, myopia and onset (occurs between the ages of 20 Case Western Reserve University’s Department of anisometropia are likely caused by and 40) and late-adult onset (occurs Ophthalmology and Visual 2,3 Sciences and director of keratoconus or other non-infl amma- after age 40). the Optometry Service at tory thinning disorders, you must Family history strongly affects the the University Hospitals Eye Institute, Cleveland, Ohio. He has have a working knowledge of the risk for youth onset and early-adult a busy medical and specialty contact lens development and epidemiology of onset myopia. For example, one par- practice and has participated in multiple clinical trials, including the Collaborative refractive error. This article can help ent with myopia increases the odds Longitudinal Evaluation of Keratoconus and you diagnose and manage patients of their child developing myopia by the National Eye Institute Refractive Error Correction Questionnaire studies. with irregular astigmatism. threefold, while two myopic parents

30 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 Regular astigmatism. Astigmatism Table 1. Causes of Corneal Irregular Astigmatism of 0.5D and higher is found in 15% of children and 40% of adults Category Causes/examples worldwide and is the most preva- Thinning Non-infl ammatory: Keratoconus, posterior keratoconus lent refractive error compared with corneal myopia and hyperopia.6 Regular Non-infl ammatory: Pellucid marginal degeneration astigmatism of more than 3D makes peripheral Terrien’s marginal degeneration, up a small percentage of astigmatic keratoglobus, dellen patients, with one study fi nding one Iatrogenic LASIK, PRK, pterygium removal in 20 individuals affected.7 Infl ammatory: Rheumatic thinning/ulcer, Mooren’s Unlike myopia, astigmatism in a peripheral ulcer, shield ulcer teenager is much less dependent on Infectious Microbial keratitis, herpetic ulcer family history, even though research Non-thinning Deposits Band keratopathy, vortex keratopathy suggests an autosomal dominant Degenerative Corneal edema 8,9 inheritance pattern. Dystrophy: epithelial Basement membrane dystrophy Asymmetry of astigmatism Dystrophy: stromal Lattice dystrophy between the eyes is also uncommon Mechanical Rigid gas permeable lens warpage (<20%) with asymmetry decreasing as astigmatism increases.10 The axis Mechanical: adnexal Ptosis of astigmatism follows mirror or Iatrogenic: corneal Cataract incision wound, radial incisions keratotomy direct symmetry in four out of fi ve patients.10 So, clinicians should have Iatrogenic: other Trabeculectomy, glaucoma shunt surgical procedures procedure, pterygium removal a high index of suspicion for ectasia in patients with asymmetrical high Traumatic Penetrating injury, foreign body amounts of astigmatism. Neoplastic: corneal Pterygium Irregular astigmatism. This is Neoplastic: adnexal Chalazion, tumor a combination of higher-order aberrations such as coma, trefoil higher-order aberrations are good NON-INFLAMMATORY and quadrafoil, each of which can predictors of keratoconus.11 CORNEAL THINNING be quantifi ed in terms of Zernike Once you’ve made the diagnosis of DISORDERS polynomials. Aberrometry allows irregular astigmatism and have ruled Keratoconus is the most common us to quantify these different types out infl ammatory corneal thinning, non-infl ammatory corneal thinning of aberrations, and research shows it’s time to consider the causes of disorder, but it’s certainly not the the detection of higher amounts of non-infl ammatory corneal disorders only one. Other thinning disor- vertical coma and overall amount of and potential treatment strategies. ders—including pellucid marginal

Release Date: June 15, 2019 in the care of patients with irregular astigmatism. Expiration Date: June 15, 2022 Estimated time to complete activity: 1 hour Accreditation Statement: In support of improving patient care, this activity has been planned and implemented by the Postgraduate Jointly provided by Postgraduate Institute for JOINTLY ACCREDITED PROVIDERTM Institute for Medicine and Review Education Group. Postgraduate Medicine and Review Education Group. INTERPROFESSIONAL CONTINUING EDUCATION Institute for Medicine is jointly accredited by the Accreditation Educational Objectives: After completing this Council for Continuing Medical Education, the Accreditation Council activity, the participant should be better able to: for Pharmacy Education, and the American Nurses Credentialing Center, to provide continuing education for the healthcare team. • Discuss the prevalence of astigmatism in the population and how Postgraduate Institute for Medicine is accredited by COPE to provide the changes that occur in astigmatism throughout life may provide continuing education to optometrists. some clues to the causes of astigmatism. • Identify the involvement and interaction of genetic and Faculty/Editorial Board: Thomas Stokkermans, OD, PhD, Case environmental factors in the development of irregular astigmatism. Western Reserve University. • Explain how corneal degenerations—non-infl ammatory corneal thinning disorders—result in irregular astigmatism. Credit Statement: This course is COPE approved for 1 hour of CE • Describe the presenting signs and features, as well as the natural credit. Course ID is 62683-AS. Check with your local state licensing progression of keratoconus and the non-infl ammatory corneal board to see if this counts toward your CE requirement for relicensure. thinning disorders. Disclosure Statements: • Review the most eff ective options—particularly surgical options Dr. Stokkermans: Nothing to disclose. (including corneal crosslinking)—for correcting keratoconus and Managers and Editorial Staff : The PIM planners and managers have other non-infl ammatory thinning disorders. nothing to disclose. The Review Education Group planners, managers Target Audience: This activity is intended for optometrists engaged and editorial staff have nothing to disclose.

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 31 PATHOLOGIC CAUSES OF IRREGULAR ASTIGMATISM Photo: Jonathan Lass, MD diagnosed KCN have the pupil (Charleaux’s “oil droplet” a one in six to one in sign), a scissored refl ex with retinos- 16 chance of having a copy and, rarely, a painful sudden family member with onset of stromal edema and opacifi - the diagnosis.12,13 cation that partially clears in weeks Besides genetics, (hydrops).12 common risk fac- In the absence of overt signs, tors determined in manual keratometry, topography, the Collaborative AS-OCT, pachymetry and aberrom- Longitudinal etry can help diagnose KCN while Evaluation of aiding in disease monitoring (Table 16 Apical scarring, together with Vogt striae, is a sign Keratoconus study 2). These tests can detect “forme of moderate keratoconus. include eye rubbing fruste” keratoconus in asymptomatic (50%) and atopy patients who are 20/20. Table 2. Amsler-Krumeich Classifi cation to (53%).15 Studies have Two well established benchmarks 17 Determine Keratoconus Severity also associated it of KCN are a central keratometry Stage I with some systemic reading of more than 47.2D and a Eccentric steepening diseases, including difference between the eyes of 0.92D Myopia and astigmatism <5D Down syndrome and or a 1.4 inferior minus superior Mean central K readings <48D Leber’s congenital (I-S) ratio.18 The I-S ratio compares Stage II amaurosis.12 corneal curvature 3mm superior and Myopia and astigmatism 5D to 8D Keratoconus inferior to the apex of the topo- Mean central K readings <53D generally develops graphical map. Absence of scarring in the second decade Another indication of KCN is Minimal corneal thickness >400μm of life, along with when pachymetry deviates about Stage III myopia and regular 10% from the expected corneal Myopia and astigmatism 8D to 10D astigmatism, and thickness (550µm) and the thin-

Mean central K readings >53D stabilizes in the fourth Photo: Jonathan Lass, MD Absence of scarring decade. It’s associated μ μ Minimal corneal thickness of 300 m to 400 m with progressive high Stage IV myopia, astigmatism, Unable to refract anisometropia and Mean central K readings >55D reduced visual acuity. Scarring is present It often develops μ Corneal thickness range of 200 m asymmetrically—one in seven patients has degeneration (PMD), keratoglobus, KCN in strictly one eye.12 The triangular deformation of the lower eyelid contour when looking posterior keratoconus and Terrien’s Clinical signs of KCN include down, or Munson’s sign, is an marginal degeneration (TMD)—may a full or partial circle of corneal indicator of advanced keratoconus.

closely resemble keratoconus, so a hemosiderin deposition that’s best Photo: Jonathan Lass, MD thorough examination is necessary visualized with cobalt blue illumi- in each case. nation (Fleischer ring), endothelial Keratoconus (KCN). This condi- vertical lines (Vogt striae), increased tion occurs in one in 500 to 2,000 visibility of corneal nerves, corneal people.1,12,13 Men and women are thinning and scarring, a V-shaped equally likely to develop KCN, and distortion of the lower lid on it’s also more common in Asians.13 downgaze (Munson’s sign), a con- Research estimates genetics contrib- ical-shaped refl ection on the nasal ute the majority (60%) of the risk.14 cornea when a light is shone from Patients with a fi rst-degree relative the temporal cornea (Rizzuti’s sign), In keratoglobus, peripheral thinning with KCN have an increased risk of a round droplet-shaped refl ection of the cornea is associated with a one in 30, and in turn, patients with observed in retro-illumination of large area of steepening.

32 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 Photos: Jonathan Lass, MD

Inferior steepening of the cornea associated with thinning Corneal hydrops in a patient with Down syndrome and at 2mm from the limbus is the hallmark of PMD. advanced keratoconus. nest point is not located within the A Fleischer ring or Vogt striae are myopia, irregular astigmatism, central 1mm or there is asymmetry not common. Because both inferior scarring in the case of hydrops and, in corneal thickness between the two KCN and PMD may reveal a “crab’s rarely, globe rupture.26 It can be con- eyes.19 The eyelid rubs on the corneal claw” or “kissing doves” topo- genital or acquired. Congenital cases epithelium about 16,000 times a day, graphic pattern, and because many can be associated with blue sclera fl attening the anterior surface in ker- topography units don’t measure be- and connective tissue disorders such atoconus. So, the posterior corneal yond the central 9mm of the cornea, as Ehlers-Danlos syndrome, Marfan curvature, and 10µm or more of el- full-diameter pachymetry is required syndrome and osteogenesis imper- evation compared with the expected to differentiate these two related fecta.26 Vision can often be corrected position, is a better indicator than conditions.24 with spectacle wear. Advanced cases anterior curvature in early KCN.20 Optical densitometry using a of keratoglobus with more thin- Classifi cation of the cone based on Scheimpfl ug camera, while a tech- ning and irregular astigmatism can

size of ectasia is standard practice; nique not available in the average Photo: Jonathan Lass, MD the three categories are “nipple optometry offi ce, can also be used cone” (less than 5mm), “oval cone” to differentiate KCN from PMD. (greater than 5mm) and kerato- Both central and inferior KCN globus (three quarters of cornea have elevated densitometry in the affected). central cornea only, while PMD has Most cases of keratoconus can elevation in the peripheral cornea as be treated with glasses and contact well. Correct diagnosis is important, lenses. But in some cases, scarring, as PMD tends to be diagnosed later excessive corneal distortion and than KCN, in the second to fi fth steepening may make it impossible decade of life, and is generally less to correct vision with contact lenses. severe. The risk for scarring is highest in Progressive, against-the-rule patients younger than age 20, those irregular astigmatism may result with corneas steeper than 52D, in the need for rigid contact lenses with corneal staining and contact or surgery. Due to the peripher- lens wearers.21 The lifetime risk of al nature, both contact lens and patients with keratoconus requiring surgical options are often modifi ed corneal transplantation is between from those used for KCN. Corneal one in fi ve to one in 10.22 collagen crosslinking may be used to Pellucid marginal degeneration. stabilize PMD.25 Unlike keratoconus, this has a male Keratoglobus. This condition pres- In posterior keratoconus, the posterior cornea is thin and the predilection and causes thinning of ents with clear, diffuse, progressive posterior fl oat is signifi cantly the peripheral inferior cornea ap- bilateral corneal thinning, especially elevated without increased curvature proximately 2mm from the limbus.23 in the periphery.26 It results in high of the corneal anterior surface.

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 33 PATHOLOGIC CAUSES OF IRREGULAR ASTIGMATISM Photo: Jonathan Lass, MD be treated with contact lenses and of the posterior cor- specialized corneal transplantation nea.30 The latter form is techniques such as tuck-in lamellar more often associated keratoplasty. with stromal scarring. Posterior keratoconus. This is gen- Because the anterior erally congenital, non-progressive, surface of the cor- often unilateral and presents with nea does not change, an abnormal posterior and normal irregular astigmatism anterior corneal curvature.27,28 When is less extreme than in congenital, a specifi c abnormality other types of kerato- is present in a layer of Descemet’s conus. When scarring membrane that forms around six is present, deprivation 29 months gestation. Researchers have amblyopia is a concern In Terrien’s marginal degeneration, a clear zone of identifi ed two subtypes, one affecting and surgical interven- thinning with thin blood vessels crossing through is a large area and the other affecting tion may be necessary. present. Opacifi cation is associated with the steep, localized central or paracentral areas In rare cases, the condi- more central edge. tion can be acquired and associated Is Keratoconus Truly a Non-infl ammatory Disorder? with trauma and interstitial kerati- Keratoconus is considered a non-infl ammatory corneal disorder tis. Because it affects the posterior because it develops in the absence of neovascularization and cornea, treatment with rigid gas corneal infi ltrates. But at the same time, a signifi cant body of permeable contact lenses is less likely literature supports a role of infl ammation in the development and to be successful. 1,2 progression of the disease. Terrien’s marginal degeneration. The association between atopy, elevated immunoglobulin E Initially, this condition affects the and keratoconus was made more than half a century ago.2 More recently, studies have found that patients with keratoconus have superior peripheral cornea asym- more infl ammatory mediators in their tears.1 metrically and causes progressive 31 Also, eye rubbing associated with eye irritation and other me- thinning. It’s associated with fi ne chanical insult to the cornea such as rigid gas permeable contact superfi cial neovascularization that lens wear, and the infl ammation caused by this, may actually be crosses over the thin zone, subepithe- the direct cause of keratoconus. In fact, in atopic patients kerato- lial opacifi cation and lipid deposition conus occurs more often on the side of the dominant hand.2 leaving a clear area between the What other evidence do we have? It seems that much of it affected cornea and the limbus.31 comes down to an inadequate balance of infl ammatory mediators Thinning can slowly progress to that may make some corneas more sensitive to mechanical insult. For instance, proteolytic enzymes and prostaglandins are upreg- affect the circumference of the cor- ulated, which promotes collagen degradation and inhibits collagen nea with a leading edge of lipid and synthesis—processes that may be responsible for thinning in kera- a central steep edge and peripheral toconic corneas. Meanwhile, upregulation of pro-infl ammatory cy- sloping edge as further hallmarks of tokines and other molecules can directly cause corneal cell death. the thin zone. Peripheral thinning And another group of mediators, including protease inhibitors and in TMD can be differentiated from anti-infl ammatory cytokines, are downregulated in keratoconus. furrow degeneration by the absence Downregulation of this group results not only in upregulation of of progression and vessels. It can be the other mediators, but also directly causes oxidative stress, col- differentiated from Mooren’s ulcer, lagen degradation, cell death and generalized reduction in immune functions. which is characterized by pain, in- Still, these results leave us with the question: Why do we fi nd fl ammation and an epithelial defect, 31 virtually no clinical and histological evidence of infl ammation as well as an absence of lipid. in patients with keratoconus? One possibility is that while both Like PMD, TMD is more com- infl ammation and keratoconus are present at the same time, there mon in men between the ages of 20 may be no causal relationship between the two. and 40 who present with increas-

1. Gatzioufas Z, Panos GD, Hamada S. Keratoconus: is it a non-inﬂ ammatory disease? Med Hypothesis ing amounts of against-the-rule or Discov Innov Ophthalmol. 2017;6(1):1-2. oblique astigmatism.31 2. Galvis V, Sherwin T, Tello A, et al. Keratoconus: an inﬂ ammatory disorder? Eye (Lond). 2015;29(7):843-59. While no systemic diseases are known to be associated with TMD,

34 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 the histopathological presence of 7. Sharif-ul-Hasan K, Ansari MZH, Ali A, et AV. Posterior keratoconus. Br J Ophthalmol. al. Relative distribution and amount of dif- 2018;102(7):863-67. large numbers of vacuoles in the ferent types of astigmatism in mixed ethnic 28. Malik TG, Khalil M, Bhatti M. Topographic affected corneal stroma may merit population of Karachi. Pak J Ophthalmol. interpretation of posterior keratoconus. Pak 2009;25(1):1-7. J Ophthalmol. 2016;32(3):186-89. further study. 8. McKendrick AM, Brennan NA. Distribution 29. Krachmer JH, Rodrigues MM. Pos- Most patients with TMD see well of astigmatism in the adult population. J Opt terior keratoconus. Arch Ophthalmol. Soc Am A Opt Image Sci Vis. 1996;13(2):206- 1978;96(10):1867-73. 14. with glasses or rigid contact lenses. 30. Rao SK, Padmanabhan P. Posterior kera- When corneal thickness is below 9. Asharlous A, Khabazkhoob M, Yekta A, toconus. An expanded classifi cation scheme Hashemi H. Comprehensive profi le of bilater- based on corneal topography. Ophthalmolo- 150µm and spontaneous perforation al astigmatism: rule similarity and symmetry gy. 1998;105(7):1206-12. patterns of the axes in the fellow eyes. Oph- 31. Ding Y, Murri MS, Birdsong OC, et al. is possible, surgical options—such as thalmic Physiol Opt. 2017;37(1):33-41. Terrien marginal degeneration. Surv Ophthal- tectonic grafting and lamellar kera- 10. Read SA, Collins MJ, Carney LG. A review mol. 2019;64(2):162-74. toplasty—should be considered.31 of astigmatism and its possible genesis. Clin Exp Optom. 2007;90(1):5-19. CE TEST ~ MAY/JUNE 2019 11. Gordon-Shaag A, Millodot M, Ifrah R, TREATMENTS Shneor E. Aberrations and topography in 1. Each of the following is a good refractive normal, keratoconus-suspect, and keratocon- predictor for keratoconus, except: ic eyes. Optom Vis Sci. 2012;89(4):411-8. A thorough review of treatment for a. Vertical coma. non-infl ammatory irregular astig- 12. Rabinowitz YS. Keratoconus. Surv Oph- b. Scissored retinoscopy refl ex. thalmol. 1998;42(4):297-319. c. High amount of unilateral astigmatism. matism is beyond the scope of this 13. Wheeler J, Hauser MA, Afshari NA, et al. d. Bilateral progressive myopia. article, but options include the use of The genetics of keratoconus: a review. Re- prod Syst Sex Disord. 2012;Suppl 6. pii:001. 2. Suspicion for keratoconus is not necessarily high rigid lenses (corneal gas permeables, 14. Szczotka-Flynn L, Slaughter M, McMahon in a teenager when: sclerals and hybrids), as well as T, et al; CLEK Study Group. Disease severity a. Retinoscopy reveals scissoring or a tear drop and family history in keratoconus. Br J Oph- refl ection. procedures such as corneal collagen thalmol. 2008;92(8):1108-11. b. Rapid onset of anisometropia, myopic crosslinking, conductive keratoplas- 15. Wagner H, Barr JT, Zadnik K. Collabora- progression and large amount of astigmatism tive Longitudinal Evaluation of Keratoconus occur. ty, intracorneal ring implants and (CLEK) Study: methods and fi ndings to date. c. Vision cannot be corrected to 20/20 in a corneal transplants. Cont Lens Anterior Eye. 2007;30(4):223-32. patient with a longstanding high amount of 16. Maeda N. Optical coherence tomogra- astigmatism. Non-infl ammatory corneal thin- phy for corneal diseases. Eye Contact Lens. d. Vision cannot be corrected to 20/20 in the ning resulting in irregular astigma- 2010;36(5):254-9. absence of amblyogenic factors and slit-lamp tism demands swift diagnosis—pref- 17. Krumeich JH, Daniel J, Knülle A. Live-epi- fi ndings. keratophakia for keratoconus. J Cataract erably at a stage when no slit-lamp Refract Surg. 1998;24(4):456-63. 3. The following clinical signs are associated with fi ndings are present—and expedient 18. Rabinowitz YS, McDonnell PJ. Comput- keratoconus, except: er-assisted corneal topography in keratoco- a. Rizzuti’s sign. intervention. Of the surgical treat- nus. Refract Corneal Surg. 1989;5(6):400-8. b. Munson’s sign. ments available, corneal crosslinking 19. Liu Z, Huang AJ, Pfl ugfelder SC. Evalu- c. Charleaux’s sign. ation of corneal thickness and topography d. Hutchinson’s sign. may have the most promise as it can in normal eyes using the Orbscan corne- be performed early in the disease to al topography system. Br J Ophthalmol. 4. A patient presents with 20/30 spectacle- 1999;83(7):774-8. corrected VA, 20/20 rigid gas permeable- arrest progression to later stages, 20. Kent C. Catching keratoconus: Mak- corrected VA, topographical simulated Ks of 4D, central corneal thickness of 400μm, and which are harder to treat. RCCL ing the tough calls. Rev Ophthalmol. 2010 Jul;17(7). Kmax of 54D. Fleischer ring and Vogt striae are present. According to the Amsler-Krumeich 1. Romero-Jiménez M, Santodomingo-Rubido 21. Barr JT, Wilson BS, Gordon MO, et al; CLEK Study Group. Estimation of the classifi cation, what stage of keratoconus is this? J, Wolff sohn JS. Keratoconus: a review. Cont a. Stage 1. Forme fruste (subclinical) Lens Anterior Eye. 2010;33(4):157-66. incidence and factors predictive of corneal scarring in the Collaborative Longitudinal keratoconus. 2. Yackle K, Fitzgerald DE. Emmetropiza- Evaluation of Keratoconus (CLEK) Study. b. Stage 2. Early keratoconus. tion: An Overview. J Behav Optometry. Cornea. 2006;25(1):16-25. c. Stage 3. Moderate keratoconus. 1999;10(2):38-42. 22. Tuft SJ, Moodaley LC, Gregory WM. Prog- d. Stage 4. Severe keratoconus. 3. Gwiazda J, Thorn F, Bauer J, Held R. nostic factors of progression to keratoconus. Emmetropization and the progression of Ophthalmology. 1994;101(3):439-47. 5. A patient cannot be corrected to 20/20 and manifest refraction in children followed topography shows a “kissing doves” pattern. 23. Martínez-Abad A, Piñero DP. Pellucid from infancy to puberty. Clin Vision Sci. Which additional test and what result will 1993;8:337-44. marginal degeneration: Detection, discrimi- nation from other corneal ectatic disorders lead to a conclusion that the patient has 4. Zadnik K, Sinnott LT, Cotter SA, et al; and progression. Cont Lens Anterior Eye. pellucid marginal degeneration (not inferior Collaborative Longitudinal Evaluation of Eth- November 22, 2018 Nov 22. [Epub ahead of keratoconus)? nicity and Refractive Error (CLEERE) Study print]. a. Pachymetry reveals thinning within the central Group. Prediction of juvenile-onset myopia. 9mm of the cornea. JAMA Ophthalmol. 2015;133(6):683-9. 24. Koc M, Tekin K, Inanc M, et al. Crab claw pattern on corneal topography: pellucid mar- b. Optical densitometry reveals elevation in 5. Grosvenor T, Perrigin DM, Perrigin J, ginal degeneration or inferior keratoconus? the central cornea but not in the peripheral Maslovitz B. Houston Myopia Control Study: Eye. 2018;32(1):11-18. cornea. a randomized clinical trial. Part II. Final report 25. Mamoosa B, Razmjoo H, Peyman A, et al. c. Full-diameter pachymetry reveals thinning by the patient care team. Am J Optom Physi- in the inferior peripheral cornea, 2mm from ol Opt. 1987;64(7):482-98. Short-term result of collagen crosslinking in pellucid marginal degeneration. Adv Biomed the limbus. 6. Hashemi H, Fotouhi A, Yekta A, et al. Res. 2016 Dec;5:194. d. The posterior corneal curvature is elevated Global and regional estimates of preva- over 10μm from expected, 4mm from the 26. Wallang BS, Das S. Keratoglobus. Eye lence of refractive errors: Systematic review inferior limbus. and meta-analysis. J Curr Ophthalmol. (Lond). 2013;27(9):1004-12. 2017;30(1):3-22. 27. Silas MR, Hilkert SM, Reidy JJ, Farooq

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 35 PATHOLOGIC CAUSES OF IRREGULAR ASTIGMATISM

6. A patient with Marfan syndrome can be corrected 8. Which is correct about Terrien’s marginal degeneration? c. Subepithelial opacifi cation with a leading edge of to 20/20, has high myopia and clear thinning of the a. Thinning develops in the inferior cornea and causes lipid. peripheral cornea. The condition is most likely: with-the-rule astigmatism. d. Thin zone has a central steep edge and peripheral a. Posterior keratoconus. b. Thinning develops in the superior cornea and causes sloping. b. Pellucid marginal degeneration. against-the-rule astigmatism. c. Terrien’s marginal degeneration. c. Thinning progresses with a calcium deposit at the 10. Levels of infl ammatory mediators are altered in d. Keratoglobus. leading edge that causes a foreign body sensation. keratoconus, indicating a possible infl ammatory cause. d. Thinning occurs at the edge of the cornea with a Which mediators are upregulated and which are 7. A fi ve-year-old patient presents with unilateral clear area that may become vascularized and will downregulated? corneal scarring and 20/60 vision in the aff ected commonly ulcerate. a. Proteolytic enzymes and prostaglandins are eye. You manage to obtain pachymetry and upregulated; protease inhibitors and anti- topography in the eye with the scars, which show 9. A 35-year-old man presents for a routine eye exam infl ammatory cytokines are downregulated. that the anterior corneal curvature is normal while due to blurred vision with his one-year-old glasses. He b. Proteolytic enzymes and prostaglandins are the posterior curvature is abnormal. You diagnose corrects to 20/25 with a large increase in against- downregulated; protease inhibitors and anti- posterior keratoconus. Which treatment should you the-rule astigmatism. Careful biomicroscopy reveals infl ammatory cytokines are upregulated. consider? superior peripheral corneal thinning. You diagnose c. Proteolytic enzymes and protease inhibitors are a. Corneal surgery. Terrien’s marginal degeneration. You expect to see the upregulated; prostaglandins and anti-infl ammatory b. A rigid gas permeable contact lens. following signs, except: cytokines are downregulated. c. Patching or atropine penalization. a. Fine superfi cial neovascularization crossing the thin d. Protease inhibitors and prostaglandins are d. Loteprednol ophthalmic gel BID for one month. zone. upregulated; proteolytic enzymes and anti- b. Clear thinning with an epithelial defect. infl ammatory cytokines are downregulated.

EXAMINATION ANSWER SHEET Mail to: Jobson Healthcare Information, LLC, Attn.: CE Processing, 395 Hudson Street, 3rd Floor New York, New York 10014 Pathologic Causes of Irregular Astigmatism Valid for credit through June 15, 2022 Payment: Remit $20 with this exam. Make check payable to: Jobson Healthcare Information, LLC. Online: This exam can also be taken online at www.reviewsce.com. Upon passing the Credit: This lesson is approved for 1 hour of CE credit. Course ID is 62683-AS. exam, you can view your results immediately and download a real-time CE ceriticate. Jointly provided by Postgraduate Institute for Medicine and Review Education Group. You can also view your test history at any time from the website. Salus University has sponsored the review and approval of this activity. Directions: Select one answer for each question in the exam and completely darken the appropriate circle. A minimum score of 70% is required to earn credit. Processing: There is a four-week processing time for this exam.

Answers to CE exam: Post-activity evaluation questions: Rate how well the activity supported your achievement of these learning objectives: 1. A B C D 1=Poor, 2=Fair, 3=Neutral, 4=Good, 5=Excellent 2. A B C D 11. Discuss the prevalence of astigmatism in the population, and how the changes that occur in astigmatism throughout life may 1 2 3 4 5 3. A B C D provide some clues to the causes of astigmatism. 4. A B C D 12. Identify the involvement and interaction of genetic and environmental factors in the development of irregular astigmatism. 1 2 3 4 5 5. A B C D 13. Explain how corneal degenerations—non-inflammatory corneal thinning disorders—result in irregular astigmatism. 1 2 3 4 5 6. A B C D 14. Describe the presenting signs and features, as well as the natural progression of keratoconus and the non-inflammatory 1 2 3 4 5 corneal thinning disorders. 7. A B C D 15. Review the most effective options—particularly surgical options (including corneal crosslinking)—for correcting keratoconus 1 2 3 4 5 8. A B C D and other non-inflammatory thinning disorders. 9. A B C D 16. Based upon your participation in this activity, do you intend to change your practice behavior? (choose only one of the following options) 10. A B C D A I do plan to implement changes in my practice based on the information presented. B My current practice has been reinforced by the information presented. Rate the quality of the C I need more information before I will change my practice. material provided: 17. Thinking about how your participation in this activity will influence your patient care, how many of your patients are likely to benefit? 1=Strongly disagree (please use a number) 2=Somewhat disagree 18. If you plan to change your practice behavior, what type of changes do you plan to implement? (check all that apply) 3=Neutral A Apply latest guidelines B Change in pharmaceutical therapy C Choice of treatment/management approach D Change in current practice referral E Change in non-pharmaceutical therapy F Change in differential diagnostics 4=Somewhat Agree G Change in diagnostic testing H Other, please specify: 5=Strongly agree 19. How confident are you that you will be able to make Identifying information (please print clearly): 22. The content was evidence- your intended changes? based. A very confident B somewhat confident First Name C unsure D not confident Last Name 1 2 3 4 5 20. Which of the following do you anticipate will be the Email 23. The content was balanced primary barrier to implementing these changes? The following is your: Home Address Business Address and free of bias. A Formulary restrictions Business Name 1 2 3 4 5 B Time constraints Address C System constraints 24. The presentation was clear City State D Insurance/financial issues and effective. ZIP E Lack of interprofessional team support F Treatment related adverse events Telephone # - - 1 2 3 4 5 G Patient adherence/compliance Fax # - - H Other, please specify: By submitting this answer sheet, I certify that I have read the lesson in its entirety and 21. Additional comments on this course: completed the self-assessment exam personally based on the material presented. I have not obtained the answers to this exam by fraudulent or improper means.

Signature: ______Date: ______Please retain a copy for your records. LESSON 118375, RO-RCCL-0619

36 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 Earn up to NEWNEW TTECHNOLOGIES 2019 19 CE & TTREATMENTS IN Credits* 9 Eye Care

CHARLESTON, SOUTH CAROLINA

Date: Program Chair: November 1-3, 2019 Paul Karpecki, OD, FAAO

Location: Charleston Marriott Early Bird Special: $420 170 Lockwood Blvd., Charleston, SC 29403 Register before September 9, 2019 for early bird pricing. Reservations: 1-800-228-9290

A limited number of rooms have been reserved at the Three Ways to Register rate of $229/night. Please book with the hotel directly Online: www.reviewsce.com/Charleston2019 by calling the number above. Mention “Review’s New Call: 1-866-658-1772 Technologies & Treatments” for group rate. E-mail: [email protected]

Partially supported by Administered by: unrestricted educational grants from: Sun Pharmaceuticals *Approval pending Bausch & Lomb Carl Zeiss Meditec Review Education Group partners with Salus University for those ODs who are licensed in states that require Alcon university credit. See www.reviewsce.com/events for any meeting schedule changes or updates. Contact Lens Wear and Its Disruption of the Tear Film A better understanding of the intricacies of this relationship can help put patients’ discomfort and other issues into better context.

By Karen Walsh, BSc(Hons), PGDip, Jaya Dantam, PhD, and Doerte Luensmann, PhD

he tear fi lm is crucial for into two different types.3-9 Additional as monocytes or macrophages, and maintaining a healthy and constituents include multiple small modulating cytokine production.13 comfortable ocular surface. molecule metabolites, peptides, an- An essential component of the im- TWhen contact lens wearers tioxidants, electrolytes and infl am- mune system, secretory IgA prevents experience dryness and discomfort, it matory mediators. The homeostasis the adhesion of microorganisms to is often from lens use. Experiencing of these components is crucial to the the ocular surface by stimulating recurrent contact lens discomfort maintenance of several vital func- their ingestion.14,15 Lipocalin is a leads to a reduction in both the num- tions of the ocular surface, including predominant lipid carrier in human ber of hours, and eventually days, hydration, lubrication, nutrition, tears and, due to its lipid binding of wear for patients, to the point of protection and modulation of optical properties, may integrate into mei- dropping out of contact lens wear properties. bomian lipids, leading to improved entirely.1 This article reviews the The initially proposed three-layer tear fi lm stability and retardation of components of the tear fi lm, its over- tear fi lm structure—mucin, aqueous evaporation.16,17 all functions, the interactions that oc- and lipid (Figure 1)—has been super- Lipids in tears are broadly clas- cur during lens wear and the actions seded by more contemporary theo- sifi ed as polar and non-polar lipids. most relevant for practitioners. ries of a multiple blended-phase tear The non-polar lipids consist of fatty fi lm. Accordingly, a superfi cial lipid acids, cholesterol esters, diesters, free COMPOSITION layer adjacent to an aqueous-mucin sterols, triglycerides and hydrocar- AND FUNCTION gel with an anchoring glycocalyx lay- The tear fi lm is an extraordinarily er has been suggested to best describe ABOUT THE AUTHORS complex, exquisite fl uid, with many the structure of the tear fi lm over the different components working ocular surface (Figure 2).10 Ms. Walsh is a clinical scientist at the Centre together to deliver several important The common proteins found in the for Ocular Research functions of vision, health and com- tear fi lm include lysozyme, lacto- & Education at the University of Waterloo in fort related to the anterior eye. The ferrin, secretory immunoglobulin Canada and is a Fellow 7 of the International appropriate balance of these compo- A (IgA) and lipocalin. Of these, Association of Contact nents is crucial, as loss of homeosta- lysozyme is the most abundant Lens Educators. 2 sis contributes to dry eye disease. in tears and is capable of killing Dr. Dantam is a laboratory The tear fi lm over the ocular sur- bacteria by breaking their outer cell scientist at the Centre 11 for Ocular Research & face has a volume of approximately walls. Lactoferrin provides antimi- Education and is a Fellow 7µL, a thickness of approximately crobial effi cacy in tears by binding of the American Academy of Optometry. 3µm to 5µm and is a highly complex free iron to reduce the availability biological fl uid that comprises of of iron necessary for microbial Dr. Luensmann is a clinical scientist at the Centre over 1,500 unique proteins, more growth and survival.12 Lactoferrin for Ocular Research & Education and is a than 600 individual lipid species also plays an important role against Fellow of the American from 17 distinct lipid classes and up infl ammation by directly interacting Academy of Optometry. to 20 distinct mucin genes classifi ed with antigen-presenting cells, such

38 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 occur from UV exposure, radiation and pollutants, thereby protecting the eye from oxidative damage.30 More than over 200 different peptides have been detected in tears. These peptides, along with the inhibition of proteases and pepti- dases, are involved in antimicrobial response that may have potential therapeutic applications for some ocular diseases.31,32 Some electrolytes found in tears include sodium, potas- sium, calcium, magnesium, chloride and bicarbonate. Measurement of tear electrolytes may help identify and differentiate dry eye severity.33 Several other tear components that require further investigation. These Fig. 1. Graphic representation of the tear fi lm. include infl ammatory mediators, Adapted from Butovich IA, Millar TJ, Ham BM. Curr Eye Res. 2008;33(5):405-20. such as IL-1 beta, increased concen- bons, while the polar lipids primarily and conjunctiva during blinking.23,24 trations of which have been reported consist of phospholipids and omega Additionally, these mucins contribute with contact lens wear.34 hydroxy fatty acids.18 Many believe to the epithelial barrier by restrict- the non-polar lipids prevent tear ing bacterial and viral access to the CONTACT LENS evaporation, provide a clear optical epithelium and participating in cell INTERACTIONS surface and present an external bar- interactions.25 Furthermore, research- Because the tear fi lm consists primar- rier against foreign bodies.19,20 ers hypothesize that gel-forming mu- ily of water and contains different In contrast, polar tear lipids, via cins are capable of trapping foreign components, it is not surprising that their amphiphilic properties, pro- bodies and pathogens and clearing the concentrations of some of these vide an intermediary between the them from the ocular surface into the components may be impacted by the outer non-polar lipid layer and inner nasolacrimal duct with the help of presence of a contact lens (Table 1). aqueous layers of the tear fi lm. This blinking.26 Contact lenses interact with the tear structure creates stability by lower- Although tear metabolites have fi lm as soon as the two are exposed ing surface tension and increasing not been studied extensively, about to each other. the viscoelasticity of aqueous tears. 60 small molecule This promotes proper segregation metabolites have been of the tear fi lm molecules, enables identifi ed, providing normal spreading of the tears and valuable insight into the prevents dehydration of the ocular dynamic biochemical surface.18,21,22 processes occurring Most of the mucins found in the within the tear fi lm.27 tear fi lm belong to two different Among the antioxidants sub-classes: membrane-spanning present in the tears, uric mucins and secretory gel-forming acid and ascorbic acid mucins. Membrane-spanning mucins account for about 50%, are found close to the epithelial with other examples surface and play critical roles in pro- including glutathi- tecting the cornea and conjunctiva one, cysteine, tyrosine by maintaining the hydration of the and vitamin D.28,29 ocular surface and providing lubrica- Antioxidants in tears Fig. 2. Graphic representation of a contact lens sitting tion and anti-adhesive properties be- help scavenge reactive with the pre- and post-lens tear fi lm. tween the cells of the ocular surface oxygen species, which Adapted from Butovich IA, Millar TJ, Ham BM. Curr Eye Res. 2008;33(5):405-20.

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 39 CONTACT LENS WEAR AND ITS DISRUPTION OF THE TEAR FILM

When the lens is applied to the break-up time (NTBUT) typically The amount of protein and lipid eye, the additional fl uid from either reduces from 15 to 30 seconds prior that deposits on contact lenses is the packaging solution or the care to insertion to fewer than 10 sec- dependent on the material com- regimen dilutes the tears initially. onds, irrespective of the material or position and other factors, such as Once in position, the contact lens wear regimen.42,43 NTBUT has been overall charge, hydrophobicity and splits the tear fi lm into two distinct reported to be signifi cantly different lens wear duration.36,46 Signifi cant layers called the pre-lens and post- between “tolerant” (20 seconds) and differences are seen between hydro- lens tear fi lm.35 At the same time, “intolerant” (13 seconds) lens wear- gel and silicone hydrogel materials; tear fi lm components start to deposit ers when they are segregated based however, few studies have found a on the lens surface, with proteins on their ability to tolerate lens wear link between tear fi lm deposition and being detectable on soft lens materi- for at least six hours.44 contact lens comfort or discomfort.47 als within seconds.36,37 Whether the baseline protein, lipid It is desirable that deposited lyso- In a healthy eye, tear fi lm thick- or mucin profi le of an individual’s zyme remains in its active state to ness is about 7µm; however, once tear fi lm can be indicative of their keep its antimicrobial properties, but a contact lens (which has a typical potential for successful contact lens studies often report a signifi cant loss center thickness of at least 70µm) has wear requires further investigation. of activity once lysozyme binds to settled on the eye, the pre-lens tear However, research shows that the certain contact lens materials, which fi lm is only about 1µm to 2µm.35 The tear protein profi le in lapsed lens could impact comfort.48,49 tear fi lm over the front surface of a wearers is different compared with The level of bacterial adhesion soft lens has a thinner lipid layer, in- that in non-lens wearers.45 One study to contact lenses is increased in the creased evaporation rate and reduced found that the amount of total pro- presence of some proteins, although tear volume compared with the tein, lysozyme and lactoferrin were research shows that viable counts normal tear fi lm.38,39 These changes lower in previous lens wearers, while were reduced in the presence of destabilize the tear fi lm, which may albumin levels and IgA-heavy chain lactoferrin deposits.50 If the ocular result in patients reporting dry eye were signifi cantly higher, indicating defense mechanism is compromised, symptoms during lens wear.40 the presence of enhanced immune the chance of developing an ocu- Possibly related to increased tear activity weeks after lens wear was lar infl ammation or infection may evaporation, another change report- discontinued.45 The authors report- increase. ed in contact lens wear is an increase ed that ocular surface changes in A focus of current, ongoing con- in osmolarity from about 284mOs- intolerant contact lens wearers did tact lens material development is to mol prior to lens wear to about not recover after a discontinuation optimize the way materials can work 313mOsmol after three months of period of three months, causing with the tear fi lm rather than against hydrogel lens wear.41 When soft con- the recurrence of ocular discomfort it—integrating with the tear fi lm tacts are worn, the noninvasive tear symptoms during the refi t attempt.45 rather than trying to resist its deposition.51 Further, new work is exam- Table 1. Changes in Tear Composition During Lens Wear ining different surface modifi cations Lipids52,53,61,65 • Reduced lipid layer thickness using components such as silver or • Lower concentration of phospholipids melimine to resist the attachment of • A higher concentration of cholesterol and an increase in degraded lipids in tears in microorganisms to the lens surface symptomatic lens wearers and inhibit its activity. The ultimate Proteins40,66,67 • Lysozme concentration unaff ected goal is to produce contact lens • No association between either lysozyme, materials that can maintain a healthy lactoferrin or lipocalin-1 levels, and contact ocular surface and tear fi lm homeo- lens comfort stasis, keeping deposited components • Higher concentration of prolactin-induced protein in dry eye patients (concentration in their natural state while optimiz- increases over the day and correlates with an ing comfort for the wearer. increase in contact lens discomfort) Infl ammatory mediators68 • Higher concentration of IL-8 in individuals with CLINICAL APPLICATION dry eye and also in contact lens wearers The application of a contact lens Mucin layer69 • Thinner with contact lens wear onto the ocular surface splits the tear • Lower concentration of certain tear fi lm fi lm in two, disrupting its structure mucins in symptomatic wearers and stability and altering the com-

40 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 position and concentration of some Table 2. Information Related to Baseline Symptoms and the Tear Film of its components.35, 40,42,43,52,53 Given Combined this knowledge, what are the most Factor Likely tolerant, Likely intolerant, relevant considerations and clinical asymptomatic, symptomatic, fi ndings for the eye care professional successful wearer unsuccessful wearer to keep in mind when reviewing their contact lens patients? Baseline symptoms (verbal, number of reported 13 Clinicians should include a thor- symptoms44) ough assessment of the tear fi lm in every examination of a contact lens Baseline symptoms (OSDI score57,58) 3.97 to 7.60 12.20 to 14.48 wearer. While we currently lack evidence to be able to use the results Tear stability (Fluorescein TBUT, secs58) 10.7±6.4 7.5±4.7 of that assessment to inform choice of contact lens material or replace- Tear stability (NITBUT, secs44,57,58) 17.0–22.7 12.0–14.9 ment frequency, evidence suggests that a combination of measures can Tear volume (Phenol red thread, mm44) 16.4±3.2 11.9±4.2 indicate the likelihood a new patient will become a successful wearer.54-56 Tear volume The combined results of baseline (Tear meniscus height, mm44) 0.43±0.1 0.31±0.1 ocular symptoms, tear stability and tear volume can indicate whether the wear compared with successful or eyelids—specifi cally the lid margins patient will be able to wear contact asymptomatic wearers who have an and, the producers of the majority lenses comfortably.44,57,58 average NTBUTs ranging between of tear fi lm lipids, the meibomian A simple approach for symptom 17 and 23 seconds.44,57,58 glands.62 All contact lens wearers assessment is asking the patient to Tear volume can be estimated should have their meibomian glands describe how their eyes feel. Three by invasive techniques such as the examined. Check if the gland orifi ces or more descriptors such as dry or Schirmer test or phenol red thread are open or blocked. Can meibum be stinging eyes indicate an increased test. These have particular appli- expressed, and what is the consisten- chance of being intolerant with con- cation for the assessment of dry cy of the meibum that is released? tact lens wear.44 Quantify baseline eye disease. Recording tear volume This information helps to build a symptoms by using a questionnaire, is also benefi cial in contact lens image of how well these glands are such as the Ocular Surface and wearers. It can be estimated through functioning. Wherever suboptimal Disease Index (OSDI), with the ad- measuring the tear meniscus height performance is found, appropriate vantage of being able to monitor any along the lower lid margin. While management is necessary, including change in scores over time. this value is not particularly helpful hot compresses, lid massage and While fl uorescein break-up time in isolation, when combined with hygiene, or in-practice treatments has traditionally been and still is NTBUT and baseline ocular symp- of lid debridement, exfoliation, heat routinely used to assess tear stability, toms, it becomes a useful predictor and massage therapy.63,64 it is an invasive technique, with the of future contact lens intolerance instilled drop of fl uorescein being (Table 2).44 he tear fi lm is incredibly com- around two to four times larger than The lipid layer of the tear fi lm Tplex, with a number of crucial the volume of the tear fi lm it is trying plays a crucial role in reducing tear roles in maintaining ocular health, to assess.59 The ability to use TBUT evaporation. A severely compro- comfort and vision. Components of to distinguish asymptomatic and mised or absent lipid layer leads to the tear fi lm interact with contact symptomatic wearers is improved evaporative dry eye.60 As contact lens materials as soon as they come when a practitioner uses a non-in- lens wear disrupts the lipid layer, into contact, and the addition of a vasive technique. A Placido disc, assessment of this particular tear fi lm contact lens inevitably disrupts tears, keratometer mires or corneal topog- component is imperative.40,61 Even resulting in changes at a molecu- rapher all enable NTBUT. Average in the absence of having specialized lar level and to its overall physical NTBUT measures ranging between equipment designed to estimate lipid properties. Disruption of tear fi lm 12 to 15 seconds indicate the poten- layer thickness, check tear fi lm lipids homeostasis in contact lens wearers tial for less successful contact lens by paying close attention to the can lead to reduced comfort and

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 41 18. McCulley JP, Shine W. A compositional based model 45. Giannaccare G, Blalock W, Fresina M, et al. Intolerant wearing times, which may ultimately for the tear fi lm lipid layer. Trans Am Ophthalmol Soc. contact lens wearers exhibit ocular surface impairment result in drop out from lens wear. 1997;95:79-93. despite three months wear discontinuation. Graefes 19. Craig JP, Tomlinson A. Importance of the lipid layer Arch Clin Exp Ophthalmol. 2016;254(9):1825-31. When reviewing contact lens in human tear fi lm stability and evaporation. Optom Vis 46. Jones L, Brennan NA, Gonzalez-Meijome J, et al. wearers, it is worth paying close Sci. 1997;74(1):8-13. The TFOS International Workshop on Contact Lens 20. Nichols KK, Foulks GN, Bron AJ, et al. The inter- Discomfort: report of the contact lens materials, design, attention to the quality and quantity national workshop on meibomian gland dysfunc- and care subcommittee. Invest Ophthalmol Vis Sci. tion: executive summary. Invest Ophthalmol Vis Sci. 2013;54(11):TFOS37-70. of the tear fi lm, with specifi c focus 2011;52(4):1922-9. 47. Subbaraman LN, Omali NB, Heynen M, et al. Could 21. Rosenfeld L, Fuller GG. Consequences of inter- lipid deposition on contact lenses be benefi cial?. Presen- on the function of the meibomian facial viscoelasticity on thin fi lm stability. Langmuir. tation at: BCLA Clinical Conference and Exhibition. June, glands. For some clinical presenta- 2012;28(40):14238-44. 2014; Birmingham, UK. 22. Shine WE, McCulley JP. Polar lipids in human meibo- 48. Jones L, Senchyna M, Glasier MA, et al. Lysozyme tions, it can be helpful to introduce mian gland secretions. Curr Eye Res. 2003;26(2):89-94. and lipid deposition on silicone hydrogel contact lens appropriate management as soon as 23. Argueso P. Glycobiology of the ocular surface: mu- materials. Eye Contact Lens. 2003;29(1 Suppl):75-9. cins and lectins. Jpn J Ophthalmol. 2013;57(2):150-5. 49. Subbaraman LN, Glasier MA, Varikooty J, et al. Pro- possible to help improve tear quality. 24. Gipson IK. Distribution of mucins at the ocular tein deposition and clinical symptoms in daily wear of For new wearers, collect the results surface. Exp Eye Res. 2004;78(3):379-88. etafi lcon lenses. Optom Vis Sci. 2012;89(10):1450-9. 25. Mantelli F, Argueso P. Functions of ocular surface 50. Subbaraman LN, Borazjani R, Zhu H, et al. Infl uence of symptoms and tear fi lm measures mucins in health and disease. Curr Opin Allergy Cl. of protein deposition on bacterial adhesion to contact 2008;8(5):477-83. lenses. Optom Vis Sci. 2011;88(8):959-66. together. These preliminary fi ndings 26. Gipson IK, Argüeso P. Role of mucins in the function 51. Buch J, Canavan K, Fadli Z, Scales C. The tear can help inform a useful discussion of the corneal and conjunctival epithelia. Int Rev Cytol. fi lm and contact lens wear. Contact Lens Spectrum. 2003;231:1-49. 2016;31(2):34-7. with the patient about their expec- 27. Chen LY, Zhou L, Chan ECY, et al. Characterization of 52. Yamada M, Mochizuki H, Kawashima M, Hata S. the human tear metabolome by LC-MS/MS. J Proteome Phospholipids and their degrading enzyme in the tears tations related to the comfort and Res. 2011;10(10):4876-82. of soft contact lens wearers. Cornea. 2006;25(10 Suppl wearing hours they may be able to 28. Choy CKM, Benzie IFF, Cho P. Ascorbic acid concen- 1):S68-72. tration and total antioxidant activity of human tear fl uid 53. Glasson M, Stapleton F, Willcox M. Lipid, lipase and achieve with their lenses. RCCL measured using the FRASC assay. Invest Ophthalmol Vis lipocalin diff erences between tolerant and intolerant Sci. 2000;41(11):3293-8. contact lens wearers. Curr Eye Res. 2002;25(4):227-35. 1. Craig JP, Nichols KK, Akpek EK, et al. TFOS DEWS 29. Gogia R, Richer SP, Rose RC. Tear fl uid content of 54. Wolff sohn JS, Arita R, Chalmers R, et al. TFOS II Defi nition and Classifi cation Report. Ocul Surf. electrochemically active components including water DEWS II Diagnostic Methodology report. Ocul Surf. 2017;15(3):276-83. soluble antioxidants. Curr Eye Res. 1998;17(3):257-63. 2017;15(3):539-74. 2. Nichols KK, Redfern RL, Jacob JT, et al. The TFOS 30. Chen Y, Mehta G, Vasiliou V. Antioxidant defenses in 55. Mousavi M, Jesus DA, Garaszczuk IK, et al. The utility International Workshop on Contact Lens Discomfort: the ocular surface. Ocul Surf. 2009;7(4):176-85. of measuring tear fi lm break-up time for prescribing report of the defi nition and classifi cation subcommittee. 31. Azkargorta M, Soria J, Ojeda C, et al. Human basal contact lenses. Cont Lens Anterior Eye. 2018;41(1):105-9. Invest Ophthalmol Vis Sci. 2013;54(11):TFOS14-19. tear peptidome characterization by CID, HCD, and 56. Ruiz-Alcocer J, Monsalvez-Romin D, Garcia-Lazaro S, 3. Mishima S, Gasset A, Klyce SD, Jr., Baum JL. Determi- ETD followed by in silico and in vitro analyses for et al. Impact of contact lens material and design on the nation of tear volume and tear fl ow. Invest Ophthalmol antimicrobial peptide identifi cation. J Proteome Res. ocular surface. Clin Exp Optom. 2018;101(2):188-92. 2015;14(6):2649-58. Vis Sci. 1966;5(3):264-76. 57. Pult H, Murphy PJ, Purslow C. A novel method to pre- 4. Wang JH, Fonn D, Simpson TL, Jones L. Precorneal 32. Pescosolido N, Barbato A, Pascarella A, et al. Role dict the dry eye symptoms in new contact lens wearers. and pre- and postlens tear fi lm thickness measured of protease-inhibitors in ocular diseases. Molecules. Optom Vis Sci. 2009;86(9):E1042-50. 2014;19(12):20557-69. indirectly with optical coherence tomography. Invest 58. Best N, Drury L, Wolff sohn JS. Predicting success Ophthalmol Vis Sci. 2003;44(6):2524-28. 33. Yetisen AK, Jiang N, Tamayol A, et al. Paper-based with silicone-hydrogel contact lenses in new wearers. 5. King-Smith PE, Fink BA, Hill RM, et al. The thickness of microfl uidic system for tear electrolyte analysis. Lab Cont Lens Anterior Eye. 2013;36(5):232-7. Chip. 2017;17(6):1137-48. the tear fi lm. Curr Eye Res. 2004;29(4-5):357-68. 59. Mooi JK, Wang MTM, Lim J, et al. Minimizing instilled 6. King-Smith PE, Fink BA, Fogt N, et al. The thickness of 34. Yüksel Elgin C, İskeleli G, Talaz S, Akyol S. Compar- volume reduces the impact of fl uorescein on clinical the human precorneal tear fi lm: evidence from refl ection ative analysis of tear fi lm levels of infl ammatory media- measurements of tear fi lm stability. Contact Lens Anteri- spectra. Invest Ophthalmol Vis Sci. 2000;41(11):3348-59. tors in contact lens users. Curr Eye Res. 2016;41(4):441-7. or Eye. 2017;40(3):170-4. 35. Nichols JJ, King-Smith PE. Thickness of the pre- and 7. Zhou L, Zhao SZ, Koh SK, et al. In-depth anal- 60. Craig J, Tomlinson A. Importance of the lipid layer in post-contact lens tear fi lm measured in vivo by interfer- ysis of the human tear proteome. J Proteomics. human tear fi lm stability and evaporation. Optom Vision ometry. Invest Ophthalmol Vis Sci. 2003;44(1):68-77. 2012;75(13):3877-85. Sci. 1997;74(1):8-13. 36. Luensmann D, Jones L. Protein deposition on con- 8. Lam SM, Tong L, Duan X, et al. Extensive characteriza- 61. Young G, Efron N. Characteristics of the pre-lens tact lenses: the past, the present, and the future. Cont tion of human tear fl uid collected using diff erent tech- tear fi lm during hydrogel contact lens wear. Ophthalmic Lens Anterior Eye. 2012;35(2):53-64. niques unravels the presence of novel lipid amphiphiles. Physiol Opt. 1991;11(1):53-58. 37. Hall B, Jones L, Forrest JA. Measuring the kinetics J Lipid Res. 2014;55(2):289-98. 62. Butovich IA. Tear fi lm lipids. Exp Eye Research. and activity of adsorbed proteins: in vitro lysozyme 9. Hodges RR, Dartt DA. Tear fi lm mucins: front line 2013;117:4-27. deposited onto hydrogel contact lenses over short time defenders of the ocular surface; comparison with periods. J Biomed Mater REs A. 2013;101(3):755-64. 63. Arita R, Fukuoka S, Morishige N. Meibomian gland airway and gastrointestinal tract mucins. Exp Eye Res. dysfunction and contact lens discomfort. Eye Contact 2013;117:62-78. 38. Lloyd AW, Mahalingham N, Guillon M. Tear evaporation in contact lens wear. ARVO 2004. Invest Ophthal- Lens. 2017;43(1):17-22. 10. Pfl ugfelder SC, Solomon A, Stern ME. The diagnosis mol Vis Sci. 2004;45:3890. 64. Geerling G, Tauber J, Baudouin C, et al. The inter- and management of dry eye: a twenty-fi ve-year review. national workshop on meibomian gland dysfunction: Cornea. 2000;19(5):644-9. 39. Chen Q, Wang J, Shen M, et al. Tear menisci and ocular discomfort during daily contact lens wear in report of the subcommittee on management and 11. Fullard RJ, Snyder C. Protein levels in nonstimulated symptomatic wearers. Invest Ophthalmol Vis Sci. treatment of meibomian gland dysfunction. Invest Oph- and stimulated tears of normal human subjects. Invest 2011;52(5):2175-80. thalmol Vis Sci. 2011;52(4):2050-64. Ophthalmol Vis Sci. 1990;31(6):1119-26. 40. Craig JP, Willcox MD, Argueso P, et al. The TFOS 65. Young WH, Hill RM. Tear cholesterol levels and 12. Flanagan JL, Willcox MD. Role of lactoferrin in the international workshop on contact lens discom- contact lens adaptation. Am J Optom Arch Am Acad tear fi lm. Biochimie. 2009;91(1):35-43. fort: report of the contact lens interactions with the Optom. 1973;50(1):12-6. 13. Puddu P, Valenti P, Gessani S. Immunomodulatory tear fi lm subcommittee. Invest Ophthalmol Vis Sci. 66. Masoudi S, Stapleton FJ, Willcox MD. Contact lens-in- eff ects of lactoferrin on antigen presenting cells. Bio- 2013;54(11):TFOS123-56. duced discomfort and protein changes in tears. Optom chimie. 2009;91(1):11-8. 41. Iskeleli G, Karakoc Y, Aydin O, et al. Comparison of Vis Sci. 2016;93(8):955-62. 14. Williams RC, Gibbons RJ. Inhibition of bacterial ad- tear-fi lm osmolarity in diff erent types of contact lenses. 67. Zhou L, Beuerman RW, Chan CM, et al. Identifi - herence by secretory immunoglobulin A: a mechanism CLAO J. 2002;28(4):174-6. cation of tear fl uid biomarkers in dry eye syndrome of antigen disposal. Science. 1972;177(4050):697-9. 42. Keir N, Jones L. Wettability and silicone hydrogel using iTRAQ quantitative proteomics. J Proteome Res. 15. Willcox MD, Lan J. Secretory immunoglobulin A in lenses: a review. Eye Contact Lens. 2013;39(1):100-8. 2009;8(11):4889-905. tears:functions and changes during contact lens wear. 43. Morris CA, Holden BA, Papas E, et al. The ocular sur- 68. Poyraz C, Irkec M, Mocan MC. Elevated tear interleu- Clin Exp Optom. 1999;82(1):1-3. face, the tear fi lm, and the wettability of contact lenses. kin-6 and interleukin-8 levels associated with silicone 16. Glasgow BJ, Gasymov OK. Focus on molecules: tear Adv Exp Med Biol. 1998;438:717-22. hydrogel and conventional hydrogel contact lens wear. lipocalin. Exp Eye Res. 2011;92(4):242-3. 44. Glasson MJ, Stapleton F, Keay L, et al. Diff erences Eye Contact Lens. 2012;38(3):146-9. 17. Millar TJ, Mudgil P, Butovich IA, Palaniappan CK. in clinical parameters and tear fi lm of tolerant and 69. Berry M, Pult H, Purslow C, Murphy PJ. Mucins and Adsorption of human tear lipocalin to human meibomian intolerant contact lens wearers. Invest Ophthalmol Vis ocular signs in symptomatic and asymptomatic contact lipid fi lms. Invest Ophthalmol Vis Sci. 2009;50(1):140-51. Sci. 2003;44(12):5116-24. lens wear. Optom Vis Sci. 2008;85(10):E930-8.

42 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 SAVE THE DATE

October 23-27, 2019 Orlando, FL Orange County Convention Center

Over 450 hours of 28 CE hours dedicated optometry CE to contact lenses CONTACT LENS LECTURE & SYMPOSIA SCHEDULE

Rapid Fire: Myopia Control in the Astigmatic Patient Evolving Orthok Lens Construction to Optimize Wednesday, Oct. 23 Beth T. Kinoshita, Patrick J. Caroline, Matthew Lampa, Roxanne Myopia Control Achong-Coan Randy Kojima, Patrick Caroline Prescribing Pediatric GP Lenses: From Corneal to Scleral Corneal Toric GPs- Concepts to Clinical Application Melanie J. Frogozo, Vivian P. Shibayama, Alexandra K. Williamson Friday, Oct. 25 Thomas Quinn The Science of Soft Contact Lenses Fitting Section on Cornea, Contact Lenses and Refractive Technology and the Scleral Lens Practice Beth T. Kinoshita, Matthew Lampa, Mark P. Andre Technologies Symposium: New Game and New Rules: Thomas Arnold Interpreting the ISO Guidelines to Safeguard Our Micro Vault, Macro Impact: Scleral Lenses Contact Lens Practice and OSD Patients Ocular Prosthetic Devices for the Optometrist Jason G. Jedlicka, Andrea Lasby, Greg DeNaeyer Louise Sclafani, Ed Bennett, Christine Sindt, Jennifer Harthan, Jamie Kuhn, Suzanne Sherman Carole Lakkis, Laura Periman Acknowledging and Eliminating Contact Lens Visual Wavefront Guided Contact Lenses Discomfort Nuts & Bolts of Fitting the Irregular Cornea Jason Marsack, Matthew Kauffman Erin M. Rueff Tiffany Andrzejewski, Lindsay Sicks Invisible Pain Syndromes: Why Scleral Lenses Do A Case for Specialty Contact Lenses Not Always Work Chad Rosen, Joshua Lotoczky Sunday, Oct. 27 Lynette K. Johns Proactively Prescribing and Fitting Soft Contact Advances in Contact Lens Care for the New Contact Lenses in Commercial Setup Lens Technologies Luigina Sorbara, Lakshmi Shinde Thursday, Oct. 24 Susan J. Gromacki Corneal GP Contact Lenses for Post-Surgical Demystifying Scleral Lenses Rapid Fire: Success with Multifocal Lenses Karen Carrasquillo, Muriel Schornack, Lynette Johns, Gloria Chiu, Patients Julie DeKinder, Dawn Y. Lam, Beth Kinoshita, Vinita Henry Annie Chang, Dawn Y. Lam Alan Kwok Contact Lenses for Visual Rehabilitation in Hot Topics in Scleral Lens Research Stuck in a Rut: Corneal Ulcers and Contact Lenses Keratoconus Andrew D. Pucker Justin Schweitzer, Melissa Barnett John D. Gelles Beyond Keratoconus: Scleral Lenses Following Contact Lenses for the Presbyope Ocular Trauma Saturday, Oct. 26 Janice Jurkus Ryan O. McKinnis Contact Lens Options for Irregular Corneas Rapid Fire: The Next Generation in Scleral Lens Multifocal Contact Lens Fitting: The Importance of Lakshmi Shinde, Luigina Sorbara Fitting Communication Brooke M. Messer, Sheila Morrison, Maria K. Walker, John Gelles Shalu Pal, Melissa Barnett

Schedule subject to change. Visit www.aaopt.org/2019 for updated information.

WORLD COUNCIL OF OPTOMETRY

www.aaopt.org/2019 worldcongressofoptometry.org

RCCL0619_House AAO.indd 1 5/29/19 10:21 AM Corneal Consult By Aaron Bronner, OD

Trust the Process Double-digit cylinder in a post-transplant eye can be daunting, but surgery can bring the number back down to earth and contact lenses can handle the rest.

47-year-old male THE PROBLEM presented with poor I diagnosed the patient vision. He had a corneal with pathologic irregular Atransplant 2.5 years ago astigmatism. The magni- to his right eye and a penetrating tude of this case deemed keratoplasty (PK) 10 years ago to vision correction with an his left eye for keratoconus. His optical device unfeasi- right eye declined to the point ble. If left untreated, the where he could not wear contact transplant would consti- The patient’s topography upon presentation. lenses, so he had a deep anterior tute an optical failure. lamellar keratoplasty (DALK). He of a DALK graft or transplant to reported healing uneventfully from SOLUTIONS roughly match the thickness of the recent transplant but said his Postoperative care for corneal trans- the host cornea at the interface, vision was not satisfactory and he plants aims to achieve graft preser- which could be very thin in cases of had not been able to correct it with vation and visual rehabilitation. We keratoconus, to prevent an anterior contact lenses. need to diagnose and treat allograft overhanging ledge of the graft at the rejection to prevent the need for interface. In full-thickness grafts, PRELIMINARY TESTING subsequent transplant. Visual this ledge can be placed in the The patient had an uncorrected vi- rehabilitation beyond being ﬁ t with anterior chamber where it doesn’t sual acuity (VA) of 20/400 OD and a hard lens is often an afterthought. cause any issues. If left anterior in a well-corrected VA of 20/25 OS However, high levels of astigmatism a DALK where it cannot be pushed with a hard lens. His entrance test commonly follow these transplants, posteriorly by the presence of the results were normal, and he had limiting uncorrected vision and, in patient’s own Descemet’s mem- intraocular pressures of 18mm Hg extreme cases, correctable vision. brane, this ledge can result in prob- OU. I was unable to perform au- High astigmatism after PK and lems with epithelization. Manually torefraction on his right eye. After DALK is usually explained by “shaving” the donor tissue can removing the rigid gas permeable the unequal tension placed on the result in scar tissue, producing irreg- (RGP) lens in his left eye, he was sutures that secure the transplant, ular astigmatism. -1.50 -2.25x096 to 20/30. Manifest resulting in irregular corneal cur- Combining these elements causes refraction yielded no measureable vature. Discussed less frequently is varying degrees of astigmatism. In improvement in VA. host and donor graft trephination. cases of worse-than-average astig- The slit lamp exam showed a The process of trephinating the matism, surgical remediation may DALK graft on the right eye, which donor and host tissues necessitates be required before using an RGP was secured by a running suture some pressure on the cornea, caus- or scleral lens. In extreme cases, a around the circumference of the ing it to deform slightly as the blade single intervention effort may not be graft. It was healthy, clear and passes through. This deformation able to treat the magnitude of cylin- compact, as was the PK with no occurs with both cuts (opening the der, so it is important to understand sutures. Deeper ocular structures host central cornea and creating the the surgical steps to take and the were normal in both eyes. donor button) and is not uniform order in which to take them. Based on topography, the patient between them. Attempts are then Our facility approaches extreme had 18.8D of astigmatism in his made to join the two slightly differ- levels of post-transplant astigmatism right eye, which was relatively reg- ent, imperfect circles, resulting in in a stepwise fashion, moving from ular centrally but became progres- varying amounts of astigmatism. less precise to more precise options, sively more irregular the further Astigmatism could also be caused that begins with removing all re- from the central cornea. by “shaving” the anterior portion maining sutures.

44 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 Your options include: oval-shaped. At signifi cantly • Suture adjustment or high levels of treatment, the removal to create long- size of this oval becomes thin term corneal stability. enough to create diminishing • Corneal relaxing returns in treatment. Thus, incisions to induce the amount of cylinder you fl attening. Because cor- treat with excimer laser-based neal relaxing incisions treatments should be no are more central (just The patient’s topography after total suture removal, greater than 6.0D to 7.0D. central to the graft host subsequent corneal relaxing incisions at eight Due to the limited magnitude weeks post-suture removal and subsequent PRK. interface), they tend of treatment offered by laser to be more impactful than those with PK grafts by 36 months, vision correction, we begin with limbal relaxing incisions. a corneal specialist should determine incisions, compression sutures and/ • Compression sutures to when and if sutures can be removed or wedges and move to PRK as induce steepening. to avoid creating graft dehiscence if needed. • Wedge resections to in- they are removed prematurely. duce marked steepening. The impact of suture removal AFTERMATH Removing a thin (0.1mm on astigmatism is unpredictable, We followed these steps to treat this to 0.2mm) wedge of donor so we must inform patients that patient. All sutures were removed, tissue from near the graft host removal may result in their astig- and relaxing incisions were placed interface with subsequent matism worsening but is performed four months later. Six months later, suturing causes steepening. to create a stable cornea for subse- PRK was performed. At the con- • Excimer laser ablations, or quent treatments. After sutures are clusion of this process, the patient’s phototherapeutic keratecto- removed, the patient should not uncorrected vision was 20/60, and my, to treat transplant eyes undergo further treatment for sev- he had 2.9D of moderately irregular that have pathologic refrac- eral months as the cornea stabilizes. cylinder and could correct to 20/40 tive with LASIK or photore- Repeat the process of manipulating with glasses and 20/20 with contact fractive keratectomy (PRK). the cornea and waiting for stability lenses. Though suture adjustment with after each subsequent procedure. running sutures or selective suture In my opinion, these efforts s ODs, we put a lot of pressure removal with interrupted sutures should conclude with excimer laser Aon ourselves to fi t post-trans- may fi ne-tune astigmatism early ablation, which is the most precise plant eyes with contact lenses; on, the magnitude of the effect of technique. Post-transplant excimer but, sometimes, the magnitude of these interventions is usually smaller laser ablation limitations, however, cylinder precludes the ability to fi t later in the postoperative course. do exist. First, treatment accura- a hard lens. Unless a surgery center Further, if surgical intervention is cy with excimer laser ablation is is able to mitigate the astigmatism, pursued to treat pathologic astigma- far from the level achieved with the graft will fail. Knowing your op- tism prior to suture removal and a conventional treatments in normal tions and being aware that astigma- suture breaks, the effect of surgery eyes, with one study reporting an tism improvement, but not always will be diminished. Removing all average cylinder reduction of less cylinder elimination, is attainable sutures creates long-term stability than 50%.1 Second, the ability to will allow you to educate patients for the cornea, which is important treat high amounts of astigmatism appropriately and refer them in a if a subsequent refractive surgery is limited by the treatment zone of timely fashion. RCCL is performed. Though sutures with all excimer laser applications. As 1. Bilgihan K, Ozdek SC, Akata F, et al. Photorefrac- tive keratectomy for post-penetrating keratoplasty DALK grafts can often be removed the magnitude of cylinder increases, myopia and astigmatism. J Cataract Refract Surg. safely one year postoperative and the treatment zone becomes more 2000;26(11):1590-5.

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 45 Fitting Challenges By Vivian P. Shibayama, OD

The More the Merrier When an out-of-the-ordinary case presents, make sure you have options to fall back on.

hen I started as a the nose OU. Her posi- contact lens special- tive and negative relative ist, the best advice accommodations were WI received was to within normal limits. understand and perfect a lens in each Her pupils were round, category. After gaining more experi- equal and reactive to ence, I realized having several lenses light. Her confrontation in your repertoire has its advantages. fi elds were full-to-fi nger While I have a few go-to lens designs counting. that I use most of the time, I am also Topographical imag- able to defer to other options. In the ing revealed irregular following case, I ended up choosing asymmetric bowties a scleral lens design that I don’t use OU with simulated as often but was well suited for my keratometry readings of patient. 43.32@092/40.86@002 Fig. 1. Topography showed asymmetrical bowties OD and 42.94@086/ and slightly irregular astigmatism OU. THE CASE 40.52@176 OS and A 21-year-old female presented with horizontal visible iris size was small for the HVIDs even complaints of blurred and fl uctu- diameters (HVIDs) of 12.0mm OU after pushing the lenses up. Over- ating vision that was giving her (Figure 1). refraction yielded +5.25 OD and headaches and making it diffi cult to Her slit lamp exam revealed clear +5.00 OS and brought the patient’s concentrate in school. She was using lids and lashes and clear conjunctiva VAs to 20/20- OU. The patient was reading glasses on top of her contact with deep and quiet anterior cham- thrilled with the comfort and vision lenses. She had tried a handful of bers OU. Her corneas, irises and these lenses provided, so we decided different lenses, including rigid gas lenses were normal. Her intraocular to move forward with them. permeable (RGP) lenses that she pressures were 15mm Hg OD and The BC of the lenses was fl attened could not tolerate and hybrid lenses 14mm Hg OS. to address the increase in vault from that gave her the most consistent and increasing the diameter to accommo- clear vision but were very dry, and CONTACT LENS EVALUATION date the patient’s larger-than-normal fi nally settled on Cooper Biofi nity to- Manifest refraction revealed: HVIDs. Changing the BC increased ric lenses that gave her good comfort +4.00+1.00x078 (VA of 20/25+) the power of the lens. The sag was but fl uctuating and unclear vision. OD also lowered to achieve a vault of A month ago, she was screened by +4.25+1.00x087 (VA of 20/30) 200µm. I ordered scleral lenses from a pediatric ophthalmologist to rule OS Advanced Vision Technology with out accommodative disorders and After reviewing the patient’s re- a BC of 9.08 OU, a diameter of strabismus. The exam fi ndings were sults, I discussed contact lens options 17.1mm OU and powers of +9.50 unremarkable, and she was cleared. with her. Given her previous success OD and +10.00 OS. Her contact lens prescription was with hybrid lenses and her dryness After the diagnostic contact +5.25 -0.75x170 OD and +5.50- issues and irregular astigmatism, lens fi tting, I dilated the patient 0.75x180 OS. Her presenting visual we decided on scleral RGP lenses. I with Cyclogyl to complete her acuities (VAs) were 20/30+ OD and placed diagnostic lenses with a base exam. The cycloplegic exam re- 20/25- OS. Over-refraction yielded curve (BC) of 8.04/-2.00/sag 4.6 and vealed +4.50+1.25x085 OD and -0.50 20/25+ OD and plano OS. a diameter of 16.9mm on both eyes. +4.75+1.25x087 OS with VAs of The patient’s cover test revealed Both of her eyes exhibited an 20/25+ OD and 20/30 OS. ortho at distance and at near. Her excessive sagittal clearance of 400 Cycloplegic refraction did not accommodative amplitudes were to and dropped low. The chamber show a signifi cant amount of latent

46 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUN 2019 hyperopia compared with the dry and had no complaints. For the manifest refraction. The dilated fi rst time in years, her vision was view of the posterior segment consistently clear, she no longer revealed a cup-to-disc ratio of 0.25 needed reading glasses and her OU. Everything else was within eyes were comfortable. Her pre- normal limits. I concluded that the scription was fi nalized. patient had hyperopia with irregular astigmatism OU. DISCUSSION In this modern age of scleral ORIGINAL DISPENSING lenses, we have many designs to The patient returned for a dis- Fig. 2. Autorefraction of the lens over the choose from. Some don’t use BC eye exhibited inferiorly decentered optics. pensing visit the following week. I to dictate sagittal height, which is placed the lenses and evaluated the right lens was 200µm with good advantageous for high minus kera- lens fi t and her vision. Her VAs were limbal clearance, and the central fi t toconus patients. For example, some 20/40- OD and 20/60 OS. The cen- of the left lens was slightly excessive sclerals have a standard fl at BC that tral vault was 200µm OU, but the at about 300µm. Over-refraction doesn’t change with changes in sag- lenses were dropping low. When the brought the patient’s vision to 20/20- ittal height.1 Instead, BC is used to lenses were pushed up, the patient’s OU. Even though this lens diameter address limbal fi t in these lenses. A vision improved. Autorefraction was smaller than the previous, the -23.00D keratoconus patient wear- showed an optic that was decen- limbal vault was slightly excessive. ing RGP lenses may be a -8.00D in a tered inferiorly (Figure 2). I did not The following lenses were ordered: scleral lens because of the difference perform over-refraction due to the 40/+5.50/15.7 standard periphery in BC when it is not dependent on decentered lens optics. BXO clear OD and 41/+4.50/15.7 the curvature of the cornea. Lower I ordered scleral lenses with the standard periphery BXO blue OS. powers can improve optics, lens original BC, diameter and powers in Since we did not need to adjust the mass and patient comfort. However, addition to a 2D toric haptic OU to sag or diameter much, the power of if a patient is already a high plus, raise them up and a thinner center these lenses was roughly half of the transitioning between designs like thickness to reduce their weight. original scleral lens order. I antici- this can be disadvantageous and pated that this would produce good cause lens decentration in a scleral DISPENSING REDO centration and a better fi t. lens, which results in induced astig- The lenses were placed on the pa- matism and poor vision. tient’s eyes a week later. They exhib- DISPENSING TAKE THREE hoosing a design that is clos- ited some improvement in centration The patient returned a week later, Cest to what the patient needs but were still decentered. Her VAs and the Europa lenses were placed on diagnostic fi tting is something I were 20/30- OD and 20/40- OS. on her eyes. Her VAs were 20/25+ learned how to do quickly to reduce After returning to school, the pa- OD and 20/25- OS. An over-re- chair time and increase patient tient would not be able to come back fraction of +0.50 OU brought the satisfaction. HVID, diagnosis, scleral for follow-up visits, so I decided to patient’s vision to 20/20- OU. The shape, material availability and refi t her in a different design to see if central vault of 200µm and the refractive error are all factors that I could achieve a better fi t. limbal vault were adequate OU. The need to be assessed immediately for I chose the Europa lens from patient was thrilled with the vision the best lens fi t and lasting patient 2 Visionary Optics with a 16.0mm and comfort the lenses offered, so I success. RCCL diameter to reduce the mass of the ordered them. 1. Hellem A. SynergEyes. A lens designed to fi t true scleral shape. blog.synergeyes.com/blog/a-lens- lens and achieve a lighter center of designed-to-fi t-true-scleral-shape. Accessed March gravity and BCs of 40.00 OD and FOLLOW-UP 27, 2019. 2. Johns LK, Barnett M. Contemporary scleral lenses: 42.00 OS. The central vault of the The patient returned a month later theory and application. Bentham Science. 2017.

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 47 Practice Progress By Mile Brujic, OD, and David Kading, OD

Special Considerations for Specialty Lenses Follow these four strategies for the best shot at success.

pecialty lenses give many look through a point that is nasal patients a clear and to the geometric center of the pupil. functional window to the Many of the optical properties of world. At times, fi tting soft multifocals are located on the Sthese lenses is straight- anterior surface of the lens. If a forward and follows a predictable topography measurement is taken process. At other times, we need to over the surface of a multifocal lens, be more creative to make sure these because of the differences in optical lens fi ts are ideal for patients. This properties, steeper zones associated column discusses four strategies to with more plus power will be evi- improve specialty lens success. dent. For example, when a topogra- Fig. 2. The near zone of this lens is phy measurement is taken over the decentered inferior temporally. TAKING TOPOGRAPHY surface of a near-center lens, it will Multifocal lenses provide patients be steeper centrally (Figure 1a). If a surface of most lenses, including gas an opportunity to see at distance patient is wearing a distance-center, permeable (GP) multifocals. These and at near with minimal to no near periphery lens, there will be lenses are typically designed with need for supplementary glass- steeper regions in the peripheral their distance optics in the center of es. Unfortunately, some patients portion of the lens and fl atter zones the lens and their near optics located have a diffi cult time with them. in the central portion (Figure 1b). more peripherally. Topography tak- Soft multifocals are based on the Most topographers can identify a en over the GP lens demonstrates a premise that we look through the patient’s line of sight to help you see fl atter profi le centrally and a steeper center of the lens and the distance where it is with respect to the optical profi le peripherally. When the lens and near optics focus on the retina. center of the lens on the eye. In our and line of sight are aligned appro- Neuroadaptation allows patients to experience, the closer a patient’s line priately, patients tend to do very adjust to distance and near vision of sight is to the optical center of well. If the lens is decentered from a when these lenses are fi t and worn the lens, the higher the likelihood patient’s line of sight, however, it can successfully. of success with the multifocal lens alter the optical zones and degrade The optical centers of multifocal design. A patient is usually less the patient’s visual quality at dis- lenses don’t always line up with a successful when their line of sight tance and at near (Figure 3). patient’s line of sight. Most patients diverges from the optical center of the lens (Figure CONQUERING COMFORT 2). Specialty lens There are certain cases in which designs in soft patients may be able to see remark- and scleral lenses ably well out of their specialty lenses can now alter the but experience poor comfort that position of the precludes them from being able to optics in the center wear them. Several strategies—in- of the lens to more cluding modifying lenses, switching appropriately align solutions and prescribing drops— Figs. 1a and 1b. The topography of a near-center with a patient’s may improve comfort. If patients multifocal lens (left) shows a steeper region centrally that corresponds to near optics. The topography of a line of sight. have comfort issues but do not have distance-center multifocal lens (right) shows a fl atter Topography can dry eye, they may benefi t from a region centrally that corresponds to distance optics. be taken over the Lacrisert placed in the lower fornix.

48 REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 A Lacrisert is a prescription shows us the effects of ortho-K on ophthalmic insert comprised of the cornea. Visualizing the area of hydroxypropyl cellulose. After the thinned epithelium helps guide lens insert is placed, it slowly dissolves positioning on the cornea and treat- over 24 hours, releasing demulcents ment zone placement (Figure 4). into the tear fi lm and providing more comfort.1 Teach users to place PINPOINTING PUPILS the insert in the lower fornix only There are times when pupil dila- after they have placed the lens on tion degrades the quality of vision their eye so it does not fall out. that some patients experience with An additional option for in- specialty lenses. GP multifocals are creasing comfort is a coating called designed so that the distance optics Hydra-PEG (Tangible Science) that are centrally located and the near adds hydrophilicity to provide a optics are in the periphery. When the Fig. 4. This epithelial thickness map taken after ortho-k shows an inferior more moisture-rich surface that pupil dilates, it may encroach into temporally displaced treatment zone. resists lipid deposition.2 This coating the near optics, reducing the quality is applied to the lens surface at the of distance vision. Patients under- preventing norepinephrine release time it is manufactured. Lenses with going ortho-K can have issues with into the synaptic cleft.3 this coating cannot be rinsed with night vision if the pupil enlarges Brimonidine is available in these water and should not be stored dry. into the reverse curve created in concentrations: 0.2%, 0.15%, 0.1% the cornea. Patients wearing small and 0.025%. We typically recom- ORDERING ORTHO-K diameter lenses, specifi cally those mend patients use the drops 30 Ortho-K helps manage and correct fi t for an inferiorly decentered cone minutes prior to performing critical myopia. Strategies for fi tting the lens in cases of keratoconus, may notice viewing tasks in low light levels, appropriately include optimizing reduced vision if their pupils dilate such as driving at night. We reserve the lens fi t, dispensing the right lens in low light levels past the optical this strategy for patients whose and following up with topographies zone of the lens or, in extreme cases, vision cannot be improved with re- and refractions after the patient has the outer edge of the lens. fractive correction or lens alteration. worn the lens overnight. Fortunately, there is a pharma- New technologies provide us with cological way to prevent a patient’s here are a handful of strategies greater insights to help guide our or- eyes from dilating. Alpha-2 receptors Tthat can help our specialty lens tho-K fi ts. AS-OCT gives us the abil- are located on the presynaptic nerve users successfully wear their lens- ity to measure epithelial thickness endings that innervate the dilator es. Any one technique, however, before and after treatment, which muscle. They bind excessive quanti- doesn’t always work for all patients. ties of norepineph- Knowing alternative options gives rine in the synaptic you the best chance at achieving a cleft to down-reg- good, comfortable fi t for the best ulate the release of results in these patients. RCCL further norepineph- 1. Bausch + Lomb. Lacrisert. www.bausch.com/ rine. Brimonidine, ecp/our-products/rx-pharmaceuticals/rx-phar- an alpha-2 adren- maceuticals/lacrisert. Accessed March 29, 2019. 2. Tangible Science. tangiblescience.com/pro- ergic agonist, binds fessionals/. Accessed March 29, 2019. directly to alpha-2 3. Kato COS, Shimizu K, Kamiya K, et al. Eff ects Fig. 3. At left is the topography over a well-centered of brimonidine tartrate 0.1% ophthalmic solu- GP multifocal. At right is the topography over a GP receptors to prevent tion on the pupil, refraction and light refl ex. Sci multifocal lens that is decentered inferior temporally. pupil dilation by Rep. 2018;8:9003.

REVIEW OF CORNEA & CONTACT LENSES | MAY/JUNE 2019 49 The Big Picture By Christine W. Sindt, OD

Spread Too Thin Patients with Terrien’s marginal degeneration should keep their safety glasses handy.

53-year-old white cautioned to wear glasses or eye The condition can be differenti- male presented with a protection at all times to avoid the ated from other corneal thinning long history of slowly risk of accidental perforation. disorders such as pellucid marginal increasing astigma- degeneration (PMD) based on the Atism in both eyes. He DISEASE BASICS location of the thinning. For TMD, denied pain or redness but stated TMD is a non-infl ammatory con- thinning starts superiorly and rarely his glasses were no longer working dition that causes thinning of the involves the inferior limbus. PMD for him. peripheral/limbal cornea. It typi- thinning, however, starts inferiorly His exam revealed 360 degrees cally begins on the superior cornea and only involves the cornea within of peripheral stromal thinning with and advances circumferentially. 1mm to 2mm of the inferior limbus. corneal neovascularization and lipid Opacifi cation and lipid deposits A complete differential diagnosis at the leading edge. The conjuncti- form at the edge of the thinned includes: dellen, collagen vascular va/sclera was white and quiet. area, and lacy pannus vessels form disease, sclerokeratitis, dry eye, He had a manifest refraction of throughout it. While punctate staphylococcal marginal keratitis -2.00 +5.50 x 180 OD and -3.00 epithelial erosion is possible, the and infectious corneal ulcer. +6.00 x 180 OS, yielding 20/20 epithelium generally appears intact. vision in each eye. Spontaneous perforations are rare; MAINTAINING VISION Based on these fi ndings, he was however, Descemet’s membrane Patients should be cautioned about diagnosed with Terrien’s marginal may rupture and cause intracorneal the risk of traumatic perforation degeneration (TMD), given a new swelling. Progressive, high against- and given protective eyewear. Scler- prescription, counseled on the pro- the-rule astigmatism is a classic al lenses may be indicated if vision gressive nature of the disease and refractive fi nding in TMD. does not improve with glasses. RCCL

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*Compared to SYSTANE® BALANCE Lubricant Eye Drops. References: 1. Korb D, Blackie C, Meadows D, Christensen M, Tudor M. Evaluation of extended tear stability by two emulsion based artifi cial tears. Poster presented at: 6th International Conference of the Tear Film and Ocular Surface: Basic Science and Clinical Relevance; September 22-25, 2010; Florence, Italy. 2. Moon SW, Hwang JH, Chung SH, Nam KH. The impact of artifi cial tears containing hydroxypropyl guar on mucous layer. Cornea. 2010;29(12):1430-1435. 3. Davitt WF, Bloomenstein M, Christensen M, Martin AE. Effi cacy in patients with dry eye after treatment with a new lubricant eye drop formulation. J Ocul Pharmacol Ther. 2010;26(4):347-353. 4. Willcox MDP, Argueso P, Georgiev GA, et al. TFOS DEWS II tear fi lm report. Ocul Surf. 2017;15:366-403. 5. Ketelson H, Rangarajan R. Pre-clinical evaluation of a novel phospholipid nanoemulsion based lubricant eye drop. Invest Ophthalmol Vis Sci. 2017;58:3929. 6. Ogundele A, Ketelson H, et al. Preclinical evaluation of a novel hydroxypropyl-guar phospholipid nanoemulsion lubricant eye drop for dry eye disease. Poster presented at: The 36th World Ophthalmology Congress (WOC); June 16-19, 2018; Barcelona, Spain. 7. Craig J, Nichols K, Akpek E, et al. TFOS DEWS II defi nition and classifi cation report. Ocul Surf. 2017;15:276-283. 8. Lane S, Paugh J, et al. An Evaluation of the in vivo Retention Time of a Novel Artifi cial Tear as Compared to a Placebo Control. Invest Ophthalmol Vis Sci. 2009;50(13):4679. 9. Benelli U. Systane® lubricant eye drops in the management of ocular dryness. Clin Ophthalmol. 2011;5:783-790. 10. Torkildsen G. The eff ects of lubricant eye drops on visual function as measured by the Inter-blink interval Visual Acuity Decay test. Clin Ophthalmol. 2009;3:501-506.

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