Figure 6. Tomography of the right eye during the follow-up Figure 6. Tomography of the right eye during the follow-up visit in March 2019. Figure 3. The Pentacam’s BAD for the right eye at the initial Figure 3. The Pentacam’s BAD for the right eye at the initial consultation. One year later, the patient returned for for the patient returned One year later, intervention. He again denied rubbing intervention. He again denied rubbing he had The patient stated that his eyes. lenses up wearing contact essentially given preferred he since his previous visit, that spectacles, and that his vision was excellent. OD and BCVA was -5.75 -0.25 x 101º = 20/20-1 a follow-up visit to determine whether determine whether to a follow-up visit keratoconic progression, if present, warranted D; MICHAEL W. BELIN, MD; AND WILLIAM B. TRATTLER, MD MD; AND WILLIAM B. TRATTLER, MD D; MICHAEL W. BELIN, h Figure 5. The Pentacam’s BAD for the left eye at the initial Figure 5. The Pentacam’s BAD for the left eye at the initial consultation. Figure 2. Tomography (Pentacam) of the right eye at the Figure 2. Tomography (Pentacam) of the right eye at the initial consultation. rubbing his eyes or sleeping in positions that that his eyes or sleeping in positions rubbing his on have put mechanical pressure might = 20/20 OD -5.25 -0.50 x 133º eyelids. BCVA was and -3.75 -1.50 x 100º = 20/20 OS. Pachymetry each point of the thinnest measurements at and the right in were 520 µm and 492 µm cornea of the examination left eyes, respectively. An unremarkable of each eye was anterior segment (Figures 1–5). | JULY 2019 | JULY

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Six months later, in February 2018, the patient the patient in February 2018, Six months later, A 46-year-old man has a long history of myopic history of myopic has a long A 46-year-old man CASE PRESENTATION Figure 4. Tomography of the left eye at the initial consultation. Figure 1. Curvature mapping of each eye using the Atlas 9000 Corneal Figure 1. Curvature mapping of each eye using the Atlas 9000 Corneal Topography System at the initial consultation in February 2018. presented to Duke University School of Medicine Medicine School of University presented to Duke he denied During this visit, consultation. for a astigmatism that was successfully managed with with managed successfully astigmatism that was patient had This daily soft toric contact lenses. periodically contemplated refractive surgery, but with then his local ophthalmologist diagnosed him examination. early keratoconus during an BY ALAN N. CARLSON, MD; RENATO AMBRÓSIO JR, MD, P BY ALAN N. CARLSON, Surgeons discuss the evidence and how they would manage this case. would manage they how the evidence and Surgeons discuss

KERATOCONUS? DOES THIS PATIENT HAVE HAVE PATIENT THIS DOES CATARACT & REFRACTIVE SURGERY TODAY

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-3.50 -1.75 x 091º = 20/20 OS. Pachymetry Do the findings in this case meet your criteria recommend intervention at this time? Regardless, measurements at the thinnest point of each for keratoconus? What, if anything, would be what follow-up care would you suggest? cornea were 526 µm and 501 µm in the right and necessary for you to make a diagnosis of forme left eyes, respectively (Figures 6–9). fruste keratoconus in this case? Would you —Case prepared by Alan N. Carlson, MD

Figure 7. The Pentacam’s BAD for the right eye at the Figure 8. Tomography of the left eye during the Figure 9. The Pentacam’s BAD for the left eye at the follow-up visit. follow-up visit. follow-up visit.

and the Belin ABCD Progression Display (Figure 11) on the Pentacam by considering front (A) and back (B) radius of curvature at the thinnest point, thinnest value (C), and distance corrected visual acuity (D). The right eye has a stable front surface curvature with a RENATO AMBRÓSIO JR, MD, PhD relatively normal pattern despite mild inferior steepening. Figures 2 and 6 demonstrate normal and stable thickness Screening for ectasia risk is a major concern when we maps and front and back elevation maps considering the consider a patient’s candidacy for corneal laser vision 8-mm best fit sphere. The BAD is lower than 1, and the correction (LVC). Enhanced screening uses a multimodal maximum Ambrósio relational thickness was greater than approach, including the analysis of curvature data from 390 µm at both visits. The left eye exhibits typical findings Placido disc–based corneal topography to detect mild of mild keratoconus—an asymmetric bowtie and pattern ectatic corneal disease, but that’s not all.1 Our ultimate goal of inferior steepening, which are identified as KC1 by the is to assess the cornea’s intrinsic susceptibility to ectatic progression while also evaluating the risk of biomechanical decompensation after LVC.2 Considering the significant variability in the subjective classifications of corneal topography maps,3 there is a fundamental need to acquire objective data such as the main deviation value from the Belin/Ambrósio Enhanced Ectasia Display (BAD).4,5 Corneal tomography data from the Pentacam (Oculus Optikgeräte) for this patient are available from February 2018 and March 2019 (Figure 10). Curvature data from Courtesy of Renato Ambrósio Jr, MD, PhD Placido disc-based corneal topography (Atlas 9000 Corneal Topography System, Carl Zeiss Meditec) are available from the first time point, and they are identical to the topometric data obtained with rotating Scheimpflug tomography on the Pentacam. Although warpage from contact lens wear is possible, the irregular shape of the cornea in each eye had not changed over 1 year of follow-up when the patient said he did not wear contact lenses. The stability of corneal shape Figure 10. Comparative display of the axial front curvature from both eyes in February can be appreciated on the comparative display (Figure 10) 2018 and March 2019.

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- - - 10,11 9 MICHAEL W. BELIN, MD MICHAEL W. BELIN, MD The TBI and the epithelial thickness data thickness epithelial the and TBI The 8 The examination in February 2018 found ectatic changes inchanges ectatic found 2018 February in examination The Finally, considering the overall clinical data, including theincluding data, clinical overall the considering Finally, the left eye with abnormalities on both the anterior and pos and anterior the both on abnormalities with eye left the finala and progression, pachymetric abnormal cornea, terior keratoconusfor definitive are findings These 4.84. of D overall stan for contraindication strong a considered be should and eyestwo the between asymmetry High surgery. refractive dard µm.28 of point thinnest the at difference a with present, also is norm. the from deviations standard two than more is This wouldI and eyes, not patients, exclude evaluations Refractive eye.right his of status the of regardless patient this treat not level of correction and the patient’s age, custom surfacecustom age, patient’s the and correction of level refractiveelective an as patient this for option an is ablation andLASIK as such procedures LVC Lamellar procedure. greaterthe to due options good be not would SMILE to fundamental is it However, impact. biomechanical theincluding ectasia, about patient this educate thoroughly IWhile prohibited. is rubbing eye that and up follow to need patientthe LVC, with CXL prophylactic recommend not do surgeryafter indicated be may CXL that understand must after progression ectatic for risk higher a be may there and theof level the Considering PRK. including LVC, of form any couldIOL phakic a of implantation correction, refractive lowerthe understand must patient The considered. be also refractivebetween differences the accept and predictability procedures. therapeutic and OCT imaging of the cornea with epithelial mapping wouldmapping epithelial with cornea the of imaging OCT interest. of be also abla surface customized whether on guidance provide may treatment. individualizing for as well as appropriate is tion Figure 12. Advanced analysis of Pentacam data with the PRFI. of Pentacam data with the PRFI. Figure 12. Advanced analysis The PRFI The 6

For this reason, Ireason, this For 6 7 | JULY 2019 | JULY

= .006; DeLong’s test). Interestingly,test). DeLong’s .006; = P CASE FILES Other data that would be part of my routine evaluationroutine my of part be would that data Other I was able to perform an advanced tomographicadvanced an perform to able was I eye,left the in ectasia confirm described parameters The A novel parameter, the Pentacam Random Forest IndexForest Random Pentacam the parameter, novel A

would highly recommend using the measurement obtainedmeasurement the using recommend highly would calculateto order in Optikgeräte) (Oculus ST Corvis the with TBI.the wavefrontocular and status, endothelial length, axial are spectral-domain high-definition of results The measurements. VAE-NT. I wish to emphasize that the integration ofintegration the that emphasize to wish I VAE-NT. biomechanicalcorneal and tomography corneal Scheimpflug ectasia;subclinical detecting of accuracy the augments data 79%,and 90.4% sensitivityof found I and colleagues my IndexBiomechanical and Tomographic the with respectively, VAE-NT. with eyes 94 in BAD the and (TBI) after LASIK (n = 71) with 96.6% specificity. 96.6% with 71) = (n LASIK after files)(u12 data raw the using by patient this for evaluation andeye right the in 0.11 was which PRFI, the calculate to 12).(Figure eye left in 0.98 constituteseye right the of presentation clinical the whereas the BAD (area under the curve = 0.960, 87.3% sensitivity,87.3% 0.960, = curve the under (area BAD the specificity; 97.5% forsensitivity 85.2% provided 0.12 of cutoff optimized the verywith eyes in topography normal with eye fellow the sensitivity80% and 188) = n (VAE-NT; ectasia asymmetric ectasiadeveloped subsequently that eyes for preoperatively (PRFI), was developed using artificial intelligence to improveto intelligence artificial using developed was (PRFI), tomographicon based susceptibility ectasia of detection study. case-controlled multicenter a from data areaan had 0.22 of value cutoff The 1. to 0 from ranges 98.8%and sensitivity 94.2% with 0.992, of curve the under thanaccurate more statistically being this specificity, 4 and 8 demonstrate a coincident thinnest point and theand point thinnest coincident a demonstrate 8 and 4 backand µm) (15 front of elevation highest with points Cornealsphere. fit best 8-mm the considering surfaces µm) (42 that,such eye, left the in stable relatively remained tomography maximumthe and 2.6 than higher was BAD the visits, both at µm.350 than lower was thickness relational Ambrósio Pentacam’s Topographical Keratoconus Classification. FiguresClassification. Keratoconus Topographical Pentacam’s Figure 11. Belin ABCD Progression Display. Figure 11. Belin ABCD Progression Figures 11 and 12 courtesy of Renato Ambrósio Jr, MD, PhD MD, Jr, Ambrósio Renato of courtesy 12 and 11 Figures CATARACT & REFRACTIVE SURGERY TODAY

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for refractive surgery. Placido-disc topography (Atlas 9000) and tomography (Pentacam) demonstrated a relatively normal right eye and early keratoconus in the left eye. The devices Courtesy of Michael W. Belin, MD documented significant inferior steep- ening in the left eye. The Pentacam also demonstrated significant asymmetry between the eyes for various other parameters. The maximum keratome- try reading is significantly steeper in the left versus the right eye, and corneal thickness is significantly thinner in the left eye. The thinnest point in the left eye is also displaced inferiorly, another Figure 13. The Belin ABCD Progression Display graphically shows changes on the anterior (A) and posterior (B) radius sign consistent with keratoconus. of curvature taken from a 3-mm optical zone centered on the thinnest point and the thinnest corneal point (C) and Additionally, the left eye has an abnor- distance (D) visual acuity. (Visual acuity is entered by the operator and was not entered for this patient.) This display notes whether there has been statistically significant change compared to both a normal population and a keratoconic mal percentage thickness increase dis- population at both the 80% and 95% confidence intervals. play as well as an abnormal BAD score. All of these signs support a diagnosis of unilateral keratoconus in the left eye. The question is what treatment, Historically the term described an eye On a positive note, the patient was if any, should be suggested. An that appeared normal at the slit lamp, monitored for a year, and repeated examination 13 months later seemingly keratometer, and optical pachymeter maps demonstrated stability. One way found no significant progression, but in a patient who had obvious kerato- to look for subtle changes over time the BAD was designed for refractive conus in the contralateral eye.13 The is a difference map, which was not screening, not for determining ectatic term predated modern imaging and provided. A difference map highlights progression. The newly released Belin is thus more historical than useful. changes in corneal shape over time. ABCD Progression Display was specifi- Unfortunately, forme fruste keratoconus Slight steepening inferiorly and flat- cally designed to follow ectatic change is currently used to describe a wide tening superiorly (see Figure 14 for over time.12 It documents change on range of findings from normality to an example from a different patient) each anatomic level and shows when frank ectasia. There are even reports would support mild progression. statistically significant change occurs. In of bilateral forme fruste keratoconus, Because there can be some variability the sample left eye shown in Figure 13, which by historical definition is an from test to test, repeat testing may no ectatic progression is evident either impossibility. be performed on a different date on the anterior or posterior corneal to confirm any changes noted on a surface or in the corneal thickness. difference map. Based on this patient’s excellent vision, lack of documented progression, and age of 42 years, I would observe him and not consider CXL at this time. No consideration of treatment is necessary for the normal-appearing WILLIAM B. TRATTLER, MD right eye, which is also stable on the progression display. I would Unilateral keratoconus is Courtesy of William B. Trattler, MD recommend continuing to observe likely common, but it often goes the patient annually. The fact that he unrecognized. This patient, for prefers spectacles over contact lenses example, was asymptomatic, his is advantageous because lens warpage slit-lamp examination was normal, will not be an issue in determining and his BCVA was 20/20 OU. He was change if it occurs. diagnosed with keratoconus only Figure 14. A difference map for another patient shows I do not use the term forme fruste when topography was performed to slight steepening inferiorly and flattening superiorly, keratoconus because I think it is useless. determine whether he was a candidate suggesting progressive ectasia.

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Cornea

D h ALAN N. CARLSON, MD . 2012;31(6):595-599. . 2003;44:812. Executive Advisory Board Cornea CRST Universidade Federal de Estado do Rio de Janeiro, Universidade Federal de Estado do Rio de Janeiro, Rio de Janeiro Corneal Tomography and [email protected] Financial disclosure: Consultant (Alcon, Carl Zeiss Professor of Ophthalmology and Vision Science, [email protected] Financial disclosure: Chief Medical Officer Director of Cornea, Center for Excellence in Eye Professor, Department of Ophthalmology, Professor, Department of Ophthalmology, [email protected] Financial disclosure: None VisareRio, Rio de Janeiro, Brazil Instituto de Olhos Renato Ambrósio, Universidade Federal de São Paulo, Brazil [email protected] Financial disclosure: Consultant (Carl Zeiss Brazil Biomechanics Study Group, Brazil Meditec, Oculus Optikgeräte) University of Arizona, Tucson (CXL Ophthalmics); Consultant (Avedro, CXL Ophthalmics, Oculus Optikgeräte) Care, Miami Member, Meditec, Oculus Optikgeräte) Duke University School of Medicine, Durham, Durham, Duke University School of Medicine, North Carolina Rio de Janeiro, Brazil            16. Kristinsson JK, Carlson AN, Kim T. Keratoconus and obesity - a connection? AN, Kim T. Keratoconus and obesity 16. Kristinsson JK, Carlson Sci Invest Ophthalmol Vis n n n MICHAEL W. BELIN, MD n n n WILLIAM B. TRATTLER, MD n n n n 17. Gupta PK, Stinnett SS, Carlson AN. Prevalence of sleep apnea in patients SS, Carlson AN. Prevalence of sleep apnea 17. Gupta PK, Stinnett with keratoconus. are the older patients with keratoconus? 18. Carlson AN. Where 2010;29(4):479-480. SECTION EDITOR n n n P RENATO AMBRÓSIO JR, MD, n n n n @CRSTODAY - - . . n . - . -

18 Revista Cornea floppy J Refract Surg 16 FOLLOW CRSTFOLLOW ON TWITTER We haveWe Am J Ophthalmol Curr Opin Ophthalmol . 2013;29(4):230-232. . 2014;30(3):151-152. 17 . 2017;6(1):1-10. . 2009;116(10):2036-2037. sleeping insleeping J Refract Surg J Refract Surg . 2015;41(6):1335-1336. 14,15 . 2017;33(7):434-443. Ophthalmology . 2013;72:85-86. . 2008;24(6):606-609. J Refract Surg International Journal of Keratoconus and Ectatic Corneal J Cataract Refract Surg . 2011;152(2):157-162.e1. . 2017;6(1):23-33. J Refract Surg . 2010;29(2):245. 11. Henriquez MA, Izquierdo L Jr, Belin MW. Intereye asymmetry in eyes with keratoconus and high ammetropia: Scheimpflug imaging analysis. Am J Ophthalmol 14. Carlson AN. Keratoconus. 15. Carlson AN. Expanding our understanding of eye rubbing and keratoconus. Cornea 2018;195:223-232. 7. Ambrósio R Jr, Lopes BT, Faria-Correia F, et al. Integration of Scheimpflug- based corneal tomography and biomechanical assessments for enhancing ectasia detection. 8. Salomão MQ, Hofling-Lima AL, Lopes BT, et al. Role of the corneal epithelium measurements in keratorefractive surgery. 2017;28(4):326-336. 9. Ambrósio R Jr. Cirurgia refrativa terapêutica: por que diferenciar? Brasileira de Oftalmologia 10. Khachikian SS, Belin MW, Ciiolino JB. Intrasubject corneal thickness asym metry. 2015;34(suppl 10):S57-60. 12. Belin MW, Meyer JJ, Duncan JK, et al. Assessing progression of keratoconus & crosslinking efficacy: the Belin ABCD Progression Display. International Journal of Keratoconus and Ectatic Corneal Diseases 13. Belin MW, Asota IM, Ambrósio R Jr, Khachikian SS. What’s in a name: keratoconus, pellucid marginal degeneration and related thinning disorders. recommended screening patients withpatients screening recommended conditions. these for keratoconus 1. Ambrósio R Jr, Randleman JB. Screening for ectasia risk: what are we screen ing for and how should we screen for it? 2. Ambrósio R Jr, Belin M. Enhanced screening for ectasia risk prior to laser vision correction. Diseases 3. Ramos IC, Correa R, Guerra FP, et al. Variability of subjective classifica tions of corneal topography maps from LASIK candidates. 2013;29(11):770-775. 4. Ambrósio R Jr, Luz A, Lopes B, Ramos I, Belin MW. Enhanced ectasia screening: the need for advanced and objective data. 5. Ambrósio R Jr, Ramos I, Lopes B, et al. Ectasia susceptibility before laser vision correction. 6. Lopes BT, Ramos IC, Salomão MQ, et al. Enhanced tomographic assessment to detect corneal ectasia based on artificial intelligence. genetic susceptibility exists in otherin exists susceptibility genetic developnot do who members family avoidthey because process disease the eyes, their rubbing theiron pressure put that positions refrac corneal undergoing and eyes, haveI and colleagues My surgery. tive associationssystemic observed also highera including keratoconus, with obesity, morbid of incidence sleep obstructive and syndrome, eyelid palate). soft (floppy apnea - - - - in medicinein Cataract & Refractive Surgery Today CRST CASE FILES forme fruste forme ALAN N. CARLSON, MD ALAN N. CARLSON, MD The term The This case raises several relevantseveral raises case This I would educate this patient onpatient this educate would I with so-called unilateral keratoconus.unilateral so-called with isthere that told are patients Many yetkeratoconus, for basis genetic a keratoconuswith patients of 7% only theof history family positive a have athat possible therefore is It disease. to contribute to this article. article.this to contribute to atten is that process disease a implies hasit and aborted, or halted, uated, unaffectedthe describe to used been patienta in eye not-yet-affected the or including the complexity surround complexity the including anand changes corneal mild ing amI keratoconus. of diagnosis official andBelin, Ambrósio, Drs. that pleased leadingworld’s the of Trattler—three willingtopic—were this on authorities and common points of discussion,of points common and sion early allows intervention (CXL) to(CXL) intervention allows early sion occur sooner. eyes, and I would recommend that hethat recommend would I and eyes, months6 in visit follow-up a for return hashe that says patient The year. 1 to rec not would I so vision, excellent said,That time. this at CXL ommend forrisk at still are 40s their in patients progres catching and progression, the importance of not rubbing his rubbing not of importance the REFRACTIVESURGERY s