Chapter 14

Presbyopia Correction

Introduction...... 208

Nonsurgical Methods for Correction of Presbyopia...... 209

Surgical Methods for Correction of Presbyopia...... 210

Laser Assisted Presbyopia Corrections25,26...... 216

Conclusion...... 217 14. Presbyopia Correction

Pulak Agarwal, Chirakshi Dhull, Yogita Gupta, and Sudarshan Khokhar

Introduction (AP). Thus, it proposes loss of lens capsule elasticity as the main cause of loss of accommodation. Loss of accommodative amplitude due to aging is known as presbyopia. Symptoms include diminution of vision for near Schachar Theory3 sight, headache, asthenopia, and eye strain.

Many plausible mechanisms in the form of theories have It proposes that during ciliary contraction, the tension in been proposed for accommodation (Fig. 14.1), equatorial zonular fibers increases, which leads to steepen- ing of anterior lens capsule. With aging, the distance between Helmholtz Theory1,2 ciliary body and the equatorial lens capsule decreases, which causes ineffective tension generation. Most of the scleral- It proposes that when the ciliary body is relaxed, the based interventions are based on this theory. zonules are stretched, which lead to flattening of anterior lens capsule and decrease in the diameter (AP) of the lens. Catenary Theory As opposed to when the ciliary body contracts, zonules are slackened; due to lens capsule elasticity, the anterior cap- It proposes ciliary body, zonules, lens, and anterior vitreous, sule steepens, which causes an increase in lens diameter as a part of diaphragm. Contraction of ciliary body causes

Ciliary muscle Contracts Contracts

All zonules Zonules relax and curl Centre zonules become tight

Central part of Tension in lens becomes lens causes it thicker and to become more steeply rounder curved

Front and back zonules relax and curl

Unaccommodated lens Accommodated lens Accommodated lens Helmholtz theory Schachar theory

Fig. 14.1 Illustration depicting various mechanisms of accommodation. Presbyopia Correction 209 increase in vitreous pressure, which leads to anterior shift of Spectacles lens and, thus, accommodation. They come in a variety of designs and materials. A person What Happens with Age? can use different sets for near and distance vision. If this is tedious, near vision can be incorporated over the distance The reason for the age-related decline in the amplitude of correction in the same pair of glasses. accommodation is not fully understood. Evidence suggests The drawback being that it does not account for interme- ciliary muscle atrophy and increase in connective tissue diate vision. To account for this problem, many designs have 4,5 over time may lead to ciliary muscle weakening. come up. Bifocal, trifocal, and progressive are few of the In addition to this, lens becomes thicker and stiffer with commonly used designs (Fig. 14.2). In the latter category, age, which may contribute to reduced accommodation.6 there can be hard progression or soft progression, depend- ing on the refractive error and near add transition. In cases of hard progression, there is a significant complaint of image Nonsurgical Methods for Correction of jump, which patients have great difficulty in adapting to. Presbyopia Also micromonovision can be used with spectacles to varying success. Although in this chapter, our main focus is on the surgical correction methods of presbyopia, there is also a brief over- view of more conventional methods in this section.

Single vision lens

A Distance or Near

Bifocal lens

Distance Distance BCDistance D

near near near

Trifocal lens

E Distance Intermidate Near

Progressive lens

F Distance Fig. 14.2 A monofocal lens B, C, D. Bifocal lens– C-shaped, D-shaped, and executive Near bifocal lens C. Trifocal lens D. Progressive lens. 210 Chapter 14

Contact Lens associated with these designs are induction of aberrations, reduced contrast sensitivity, glare, halos, etc. Contact lenses can be used in many different ways to help Modified micromonovision can be used with the multifo- with the problem of presbyopia: cal lenses, in which one eye can be corrected for distance, Monovision and the other eye can have multifocal multifocal near add. Also, simultaneous multifocal contact lenses in both eyes It is the method most commonly resorted to. Dominant can be used either with same design (center distance or eye is corrected for distance and nondominant eye for near center near) or crossover designs. Crossover designs may vision. Acceptance rate is generally good. Optimum addi- have a little more success as compared with the former. tion is generally + 1.5D. Addition more than this may cause There is a limited research that has been conducted on difficulty in stereopsis and less than this may not solve the rigid gas permeable (RGP) lenses with multifocality. The dif- purpose of near add altogether. fractive component can be added in those to increase the range of focus. Multifocal Contact Lenses Recent literature reports use of contact lens with pin-

7 Soft bifocal or multifocal contact lenses are available in dif- hole. Near vision and intermediate vision improves with no ferent designs (center distance/center near; two rings/mul- negative effect on binocular visual field and distance visual tiple rings; Fig. 14.3). It has varying acceptance rates among acuity; although, contrast sensitivity decreases at certain patients. It is a pupil dependent method. The main problems frequencies.

Surgical Methods for Correction of Presbyopia

A On the Basis of Cornea

Inlays

Various corneal inlays have been used for correction of pres- byopia (Fig. 14.4). Below are few which are commonly used.

Kamra Inlay B It is a Food and Drugs Administration (FDA)–improved cor- neal implant. It is an opaque implant inserted in the corneal pocket created using femtosecond laser technology (depth of 200 μm). It is generally inserted in the nondominant eye. This polyvinylidene fluoride inlay has around 8400 micro C pinholes which lead to adequate perfusion anterior and posterior to the inlay. It increases the depth of focus with minimal effect on the distance visual acuity. It works on the principle of pinhole effect and causes increase in depth of focus. It can be used with simultaneous laser-assisted in-situ keratomileusis (LASIK) surgery as well and can be implanted Fig. 14.3 Types of presbyopic contact lens A. Bifocal D in nondominant eye. The main side effects are glare, halos, shaped lens B. DCentre design (Distance/ Near C. Multiple ring Design difficulty in subsequent cataract surgery, and LASIK flap- and Presbyopia Correction 211

8,400 holes (5–11µm) Thickness: 15 µm er

6 µm thin am et 1.6 mm aperture 3.8 mm di

Profile view Made from polyvinylidene fluoride (PVDF)

Fig. 14.4 Corneal inlays.

pocket-related complications (vascularization and epithelial that are being performed. This implant is no longer recom- ingrowth). Keratitis has also been reported.8 In cases with mended for presbyopia correction. unsatisfactory results, the inlay can be explanted. It should Icolens12 be avoided in patients who require night time driving. It is the most recent addition to the inlay family. It is made The results have been very encouraging with good gain up of hydrophilic acrylic hydrogel. It is very similar to flexi- in near vision and good patient satisfaction.9 On long-term vue inlay and is under FDA trials. follow-up as well, the vision remained stable with no signifi- cant change in refractive errors.10 Small Incision Lenticule Extraction Lenticule

Flexivue Inlay11 Animal study on primates shows good results for presbyopia correction using small incision lenticule extraction (SMILE) It is a hydrophilic acrylic polymer implant with an overall lenticule. Central cornea steepens and shape becomes pro- diameter of 3.2 mm. It has a central disk with no power, late. There is no postoperative corneal haze at 6 months. The which provides for distance vision and surrounding that are drawbacks include thinning of the lenticule in the postop- multiple rings of increasing power providing multifocality. erative period, with regression after a few months. There is It is a transparent inlay. It has a central hole which provides also theoretical risk of rejection of the lenticule by the host nutrition through diffusion. It is currently under FDA trials. body.

Rain Drop Inlay Jacob et al reported using SMILE lenticule for presbyopia It is a corneal reshaping inlay with no power of its own. It in four patients with good visual outcome. All the patients was FDA-approved in 2016 but has been recalled due to had good near vision (J2), decent intermediate vision, and significant corneal haze in postoperative period. Due to good distance visual acuity. There was no gross ocular dis- this haze, there is an increasing number of inlay removals comfort, glare, halos, or rejection.13 212 Chapter 14

Laser Vision Correction a disadvantage in that it leads to excessive loss of corneal tissue due to myopia correction in central PresbyLASIK cornea. Correction of presbyopia at the corneal plane by creating a Epstein et al reported 92% and 89% of spectacle multifocal ablation profile using excimer laser is achieved by independence in myopic and hyperopic patients at a procedure known as PresbyLASIK. It can be of two types: 1-year follow-up. Higher order aberrations (HOAs) 1. Central PresbyLASIK: It is achieved by creating a were increased in both the groups.15 hyperpositive area in the central cornea which helps in near vision; the peripheral area is left for distance Supracor vision. As miosis occurs during the near vision triad, It is an algorithm developed by Technolas Perfect Vision this approach seems very practical, as the central GmbH, Munich, Germany. It optimizes aberrations while area is left for near vision. It can be used in hyper- creating a hyperpositive area in the central 3 mm of cornea opes, myopes, and emmetropes. The drawback being (+ 2 near add; Fig. 14.6). It can be treated in a symmetri- the centration of the ablated area over the visual axis, cal or asymmetrical manner. In the former, both the eyes which can often be unsatisfactory, as more often are treated for near vision. In the latter, the dominant eye than not, the pupillary axis does not coincide with is treated for distance (plano) and the nondominant eye is the visual axis. treated for near. Alio et al reported the outcomes with 72% of the 25 Ryan et al reported that binocular UNVA better than 0.2 eyes having uncorrected near visual acuity (UNVA) logMar in 91% of the patients undergoing hyperopic presby- better than 20/40. Contrast sensitivities decreased opic LASIK (Supracor). HOAs were increased but there was 14 uniformly. no significant increase in trefoil and coma.16 The majority 2. Peripheral PresbyLASIK: In this procedure, a nega- (96%) of patients were happy with the procedure in this tive spherical aberration is induced in the peripheral study. cornea. Thus, the peripheral cornea is utilized for near vision and the central cornea is used for distance PresbyMax vision (Fig. 14.5). This procedure is mainly used for PresbyMAX (SCHWIND eye-tech-solutions GmbH, hyperopes. In myopic patients, this procedure is at Kleinostheim, Germany) biaspheric corneal surface is

Near vision Far vision Near vision

Cornea

Iris

Lens

Fig. 14.5 Illustration showing ablation pattern in peripheral PresbyLASIK. Abbreviation: LASIK, laser in-situ keratomileusis. Presbyopia Correction 213

Near addition Intermediate and zone Intermediate and distance zone distance zone

Pre-op cornea

Near and far in focus

Post-op cornea Central near addition

Fig. 14.6 Supracor presbyopia correction. Near add is central followed by transition zone and distance vision zone. created and multifocality is achieved by creating a hyper- Postoperatively, there are three stages of recovery which positive area from + 0.75D to + 2.50D. The area peripheral to overlap between swelling, healing, and adaptation. The this area is ablated for distance vision. adaptation part can take up to 3 to 4 months.

Uthoff17 reported good visual outcomes with 90% of It was reported that in emmetropic, myopic, and astig- emmetropic patients and 80% of the myopic and hyperopic matic patients, 96% achieved vision better than J2 (Jaeger patients having UNVA better than 0.3logRAD. scores).19,20 In hyperopic patients, only 81% achieved near

21 Luger18 reported 84% of all the patients treated using vision of J3 or better. PresbyMax had UNVA of 0.1logRAD or better. Conductive Keratoplasty

Laser-blended Vision It is based on the premise that heat denatures collagen. Presbyond Laser Blended Vision (Carl Zeiss Meditec, Jena, Eight spots are placed circumferentially at 6 mm, 7 mm, Germany) is a type of monovision in which the dominant and 8 mm from the center of optical zone. Thus, when the eye is corrected for distance and the nondominant eye is collagen denatures, it contracts and flattens the cornea in corrected for near (around 1.5D; Fig. 14.7). It is a refined the center. Stahl et al22 reported that after 1-year follow-up, version, with the refinement being that it is a wavefront- patients had good near vision. The vision improved from J10 optimized ablation which leads to low aberration profile. to J1. There were no complaints of postoperative discomfort

Preoperative workup includes: as well.

••Best-corrected near visual acuity (BCVA) and pupillary However, the major drawback is the regression overtime reactions. with this procedure and majority of the patients returning ••Manifest refraction. to their baseline error. Due to this reason conductive kerato- ••Dominance test (hole test, finger pointing test, camera plasty is not extensively in use currently. test, and rifle shooting test). ••Tolerance test (to test for cross blur). On the Basis of Intraocular Lenses ••Schirmer’s test and tear film breakup time (TBUT; Phakic Multifocal IOLs more chances of dry eye in adults). ••Corneal topography, tomography, and corneal biome- There is limited literature on use of phakic multifocal chanics (ocular response analyzer). intraocular lenses (IOLs) in presbyopia correction. 214 Chapter 14

Distance Distance

Sharp distance vision

Combined good BLEND intermediate vision ZONE

Sharp near vision

NEAR NEAR

Dominant eye Non- dominant eye ± 0.0 D − 1.5 D

Fig. 14.7 Principle of Presbyond by Zeiss Meditech; blended vision where dominant eye is treated for distance and nondominant eye is treated for near.

They can be angle-supported or implantable collamer Refractive Lens Exchange/Multifocal IOLs lenses (ICLs). The angle-supported IOL has haptic of poly- This approach is the most widespread and accepted treat- methylmethacrylate (PMMA) material and optic of hydro- ment modality for presbyopia. Multifocal IOLs has passed philic acrylic material. It has a four-point fixation. With this, through generation of modifications to reach the present 23 IOL results were satisfactory but inferior to refractive IOLs. level and there is still ongoing research to improve and Complication rate was low. But in patients with slight lens refine it even further. opalescence, there was marked reduction in visual acuity. Initially, they used to be refractive in nature with mul- The other type of phakic IOL for presbyopia is implant- tiple rings of refraction. The center of the IOL can either be able collamer lens with central hole. Due to the presence of for near or distance. The refractive multifocal IOL is pupil- central hole, iridotomy is not needed to prevent pupillary dependent and patients may have complaints of glare, halos, block and the chances of development of cataract are low. and loss of contrast sensitivity.

Preoperative workup has to be done properly with anterior Recent designs use diffractive designs (Fig. 14.8). They chamber (AC) depth of a minimum of 3 mm. It is tried as have two foci. One for near and one for distance. The dif- a monovision therapy. The postoperative results are satis- fractive steps are added on to the anterior or posterior sur- factory with reduction in spectacle dependence and good face to provide for the near focus. The distance between the vision in near and intermediate distance.24 steps determine the power of add and height of the steps Presbyopia Correction 215

Fig. 14.8 Diffraction steps (L) and apodization (R). determine the division of amount of light diffracted to near It can be achieved by using conventional method, crossover and distance foci. Some IOLs have an apodised design of method, and hybrid method. In conventional method, the diffraction steps, which means that the height of the steps dominant eye is corrected for plano, and the nondominant decreases toward the periphery. So, in mesopic conditions, eye is corrected for myopia and vice versa in crossover when more of diffraction rings are exposed, more of the light design. Generally, for successful monovision, −1.5D is an is focused for distance rather than near. This, in turn, leads acceptable myopia in the nondominant eye. For minimono- to a drawback: in dim lit situations, it is difficult to work for vision, dominant eye is implanted with monofocal IOL for near with multifocal IOLs. emmetropia. Nondominant eye is implanted with the aim of residual myopia of around − 0.75D. In hybrid monovision, More recently, trifocal lenses which provide focus for dominant eye is implanted with monofocal IOL and non- intermediate distance as well have been developed with dominant eye is implanted with multifocal IOL. It is espe- good success rates. cially useful for people younger than 60 years. The most recently FDA-approved IOL is a type of extended Studies have reported that spectacle independence with range of vision or extended depth of focus. It has an echelette monovision was comparable with multifocal IOLs. However, type of design. It has nine echelettes at the back of the IOL multifocal IOLs are generally superior in this respect. which are not exactly perpendicular but slightly angled. The Reading ability may be better with this approach as com- slight angulation leads to extended focus for intermediate pared with multifocals. Contrast sensitivity is better as com- visual acuity rather than two foci for near and distance as in pared with multifocal IOLs. Also, night time problems of glare most multifocal IOLs (Fig. 14.9). Although, the complaints of and halos are a little less with this approach. Drawbacks are glare and halos drastically decrease with this IOL but it is not poor stereoacuity and low-clarity in near and intermediate altogether eliminated. Although patients are to be counseled vision as compared with multifocal IOLs. about need of glasses for near vision, they will have good vision for most of the intermediate range of vision and dis- Accomodating IOLs tance vision. Chromatic aberrations are also very less with Although accommodating IOLs are not used in our setup, this type of IOL. Also, patient has to be counseled about a this chapter wouldn’t be complete without their mention. period of neuroadaptation that is required after implanta- These IOLs are based on the premise of changing their shape tion of this IOL. in response to ciliary body contraction, contraction of lens The most important criteria in successful multifocal IOL bag, and positive vitreous pressure. Crystalens and Trulign implantation is patient selection. toric IOL are the only two accommodating IOLs approved by FDA. Crystalens, Tetraflex, and IO human optics are the Pseudophakic Monovision most commonly used accommodating IOLs. They are all With increasing demand of spectacle independence and single optic. They have good visual outcomes; however, bag affordability, a considerable issue (especially in developing contraction with loss of accommodating ability of the IOL is countries), pseudophakic monovision is a very viable option. very common. 216 Chapter 14

Echelette side view

Elongated focus

Light

Focal length

Fig. 14.9 Principle of extended depth of focus; diffractive echelette design.

Other IOLs in development on the same lines are Nu lens Laser Assisted Presbyopia and bag filling technology. These are still under research. Corrections25,26

On the Basis of Sclera The LaserACE system uses erbium-yag laser. They use 600 μm spot size. Nine spots in a diamond matrix pattern are ablated The scleral approaches are based on the premise of Schachar using fiber optic hand piece in nine oblique quadrants of the theory of accommodation. According to Schachar, due to eye. The postulated mechanism is that it decreases the scle- aging, the lens grows in equatorial diameter, which leads ral rigidity and reduces the distance between scleral spur to decrease in distance between lens equator and ciliary and ora serrata. The latter helps in restoring the anatomi- body. The decreased distance leads to inadequate pull on cal relation of the accommodating mechanism. Preliminary zonules which, in turn, leads to inadequate zonular tension reports are encouraging with improvement in near vision and consequent loss of accommodation. The decrease in and good patient satisfaction. distance has been proven on magnetic resonance imaging (MRI). The extraocular approaches are considered safer, as Scleral Implant-based Approach they don’t have decrease in distance vision, loss of contrast, halos, glare, etc. It is based on the concept that if the distance between cili- On the above-stated premise, LaserACE (Ace Vision ary body and the lens equator is increased by pulling the Group, Silver Lake, Ohio, USA) and VisAbility Implant System sclera outward in an area of the ciliary body, effective ten- Surgery Scleral Implants (Refocus Group, Dallas, Texas, USA) sion on zonules can be increased. Thus, VisAbility Implant were developed and are still under trials for actual mecha- System Surgery Scleral Implants27 (Refocus Group, Dallas, nism of action and efficacy. Texas, USA) are rice grain-sized implants which are placed Presbyopia Correction 217 in scleral tunnels 4 mm from limbus. The procedure requires surgical compensation of presbyopia. J Cataract Refract 360 degrees conjunctival peritomy and formation of scleral Surg 2015;41(3):566–575 tunnels. Preliminary results of the trial show improvement 11. Limnopoulou AN, Bouzoukis DI, Kymionis GD, et al. Visual outcomes and safety of a refractive corneal inlay in near vision but prolonged ocular surface recovery. for presbyopia using femtosecond laser. J Refract Surg 2013;29(1):12–18 12. Bouzoukis DI, Kymionis GD, Panagopoulou SI, et al. Visual Conclusion outcomes and safety of a small diameter intrastromal refractive inlay for the corneal compensation of In the current era, various modalities are available for presbyopia. J Refract Surg 2012;28(3):168–173 correction of presbyopia. A cornea based or lens based 13. Jacob S, Kumar DA, Agarwal A, Agarwal A, Aravind R, approach may be used based on the age, requirement, Saijimol AI. Preliminary evidence of successful near vision enhancement with a new technique: PrEsbyopic amount of refractive error and nucleus status. Monovision Allogenic Refractive Lenticule (PEARL) corneal inlay using corneal procedure or lens based procedure is a fairly using a SMILE lenticule. J Refract Surg 2017;33(4): common procedure with low cost and good outcomes. In 224–229 older patients requiring permanent correction, multifocal 14. Alió JL, Amparo F, Ortiz D, Moreno L. Corneal multifocality IOLs may provide a more suitable alternate. Hence, consid- with excimer laser for presbyopia correction. Curr Opin Ophthalmol 2009;20(4):264–271 eration of variety of patient and surgery related factors can 15. Epstein RL, Gurgos MA. Presbyopia treatment by help in achieving excellent outcomes. monocular peripheral presbyLASIK. J Refract Surg 2009; 25(6):516–523 References 16. Ryan A, O’Keefe M. Corneal approach to hyperopic presbyopia treatment: six-month outcomes of a new 1. Michaels DD. Visual optics and refraction: a clinical multifocal excimer laser in situ keratomileusis pro­ approach, 3rd ed. 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LASIK for Press Inc; 1975 presbyopia correction in emmetropic patients using aspheric ablation profiles and a micro-monovision 6. Weeber HA, Eckert G, Pechhold W, van der Heijde RG. protocol with the Carl Zeiss Meditec MEL 80 and Stiffness gradient in the crystalline lens. Graefes Arch VisuMax. J Refract Surg 2012;28(8):531–541 Clin Exp Ophthalmol 2007;245(9):1357–1366 20. Reinstein DZ, Archer TJ, Gobbe M. LASIK for myopic 7. Park SY, Choi YJ, Jung JW, et al. Clinical efficacy of pinhole astigmatism and presbyopia using non-linear aspheric soft contact lenses for the correction of presbyopia. In micro-monovision with the Carl Zeiss Meditec MEL 80 Seminars in ophthalmology. Mar 10 (pp. 1–9). Taylor & platform. J Refract Surg 2011;27(1):23–37 Francis; 2019 21. Reinstein DZ, Archer TJ, Gobbe M. Aspheric ablation 8. Duignan ES, Farrell S, Treacy MP, et al. Corneal inlay profile for presbyopic corneal treatment using the implantation complicated by infectious keratitis. 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24. Kamiya K, Takahashi M, Takahashi N, Shoji N, 26. Hipsley A, Ma DH, Sun CC, Jackson MA, Goldberg D, Shimizu K. Monovision by implantation of posterior Hall B. Visual outcomes 24 months after LaserACE. Eye chamber phakic intraocular lens with a central hole Vis (Lond) 2017;4:15 (Hole ICL) for early presbyopia. Sci Rep 2017;7(1):11302 27. U.S. National Institutes of Health Clinical Trials. A 25 U.S. National Institutes of Health Clinical Trials. Clinical Trial of The VisAbility Micro Insert System for LaserACE Procedure Restore Visual Function and Range Presbyopic Patients of Accommodation LaserACE Procedure. NCT01491360