Demographic and visual outcomes on keratoconus patients with failed “epi- on”C3R cross-linking procedures Yaron S. Rabinowitz M.D. Oana Dumitrascu M.D. The authors have no financial interest in the materials presented in this poster

Background The standard procedure in collagen cross- linking is to remove the epithelium. Recent reports suggest that it is not necessary to remove the epithelium using the “ epi-on ” C3R procedure. This study was undertaken to illustrate C3R failures.

Abstract PURPOSE: To present data on unhappy keratoconus patients who presented to our office following C3R “epi-on” cross-linking. METHODS: Retrospective chart review 1 year post procedure RESULTS: 13 eyes were identified. Mean age was 33 yrs (range 23 – 41). Mean uncorrected acuity was 20/200 (range 20/40-20/200). Mean best-corrected acuity was 20/60 (range 20/30-20/200). Mean central pachymetry was 435um (range ). Mean K value was 50.27(range 43-58). Mean I-S value was 4.25(range ). 4 eyes had repeat cross-linking with the standard epi-off procedure, 4 eyes had corneal transplants and 5 eyes had no further treatment CONCLUSIONS: These data suggest that the “epi-on” C3R procedure may not be optimal for treating keratoconus.

Results - Demographics of failed “epi-on” NAge Reason for consult UCVA BSCVA K’s Pach Additional findings/surgery 114Progressed 7D in 1 year 20/400 20/80 57/53417 Clear cornea 214Progressed 8D in 1 year 20/40020/7058/52444 Intacs 326Progressed by 3D CF 2 ft20/40054/48446 Paracentral scar 428No visual improvement 20/15020/3051/49409 Intacs and ICL 528No visual improvement 20/8020/4046/42473 Intacs and ICL 632No improvement in VA 20/4020/2545/42479 Intacs and 2nd C3R 732No improvement in VA 20/8020/4050/51454 Intacs and 2nd C3R 833Rapid progression CF20/40054/41381 Intacs 936Progression worse VA 20/40 56/45418 Intacs, CK and ICL 1036Progression worse VA 20/7020/4057/48435 Intacs, CK and ICL 1142Progression worse VA 20/40020/7053/48380 Paracentral scar 1242Progression worse VA 20/15020/7050/47461 Paracentral scar 1351No improvement in VA CF 1ft 63/56381 Paracentral scar/Epi Lasik

Results - Demographics Summary of findings at presentation 4/13 (30%) eyes had paracentral scars 9/13 (70%) eyes had 1 additional surgery 6/13 (46%) eyes had 2 additional surgeries 3/13 (23%) eyes had 3 additional surgeries

Results - reasons why patients not happy 8/13(60%) patients noted progression after C3R, we were able to document this in 5 patients one progressed up to 8D 5/13(40%) did not experience an improvement in their vision which was their reason for doing the procedure

Eye 2 - Pre op and 1 year Post op topography C3R - 8 D change

Results - Disposition of Failed C3R patients NAge UCVA BSCV A K’s Pach Disposition and results /400 20/80 57/53417 I.E.K./AK UCVA 20/ /40020/7058/52444 I.E.K./LASIK UCVA 20/ CF 2 ft20/40054/48446 RGP BCVA 20/ /15020/3051/49409 Glasses BSCVA 20/ /8020/4046/42473 Glasses BSCVA 20/ /4020/2545/42479 Repeat CXL epi off UCVA 20/ /8020/4050/51454 Repeat CXL epi off UCVA 20/ CF20/40054/41381 I.E.K/LASIK UCVA 20/ /40 56/45418 Repeat CXL epi off UCVA 20/ /7020/4057/48435 Repeat CXL epi off UCVA 20/ /40020/7053/48380 RGP BCVA 20/ /15020/7050/47461 RGP BCVA 20/ CF 1ft 63/56381 I.E.K./AK UCVA 20/30

Discussion Collagen Cross Linking(CXL) involves the removal of the corneal epithelium, soaking the cornea with riboflavin and applying a homogenous beam of UV light for about 30 minutes to the cornea. Several studies in the published literature suggest that this is a safe and effective method for retarding the progression of keratoconus C3R is a variation of this procedure in which the epithelium is retained and a lamp of unknown origin is used for UV radiation. It is not FDA approved but done on an off label basis This procedure is heavily marketed as being safe and effective, with a < 2% retreatment rate being quoted For C3R,there have been no scientific studies to date demonstrating a high safety profile as has been done for CXL

Discussion In this study we demonstrate that 13 eyes from one practice performing C3R had an unfavorable outcome in a 1 year period This suggests that the “failure rate” for C3R may be higher than the quoted 1.4% “retreatment rate” 5/13 eyes were unhappy because they noticed no visual improvement, 4 had paracentral scars 8/13 eyes noted definite progression within 1 year of receiving the treatment This suggests that patient selection for this particular procedure might have been less than optimal

Conclusion While Collagen Cross linking (CXL) appears to be safe and effective as described by the pioneers of this procedure, it appears that performing this procedure leaving the epithelium on requires further study for safety and efficacy, before being universally adopted. Patients expectations for improved vision should be tempered with the emphasis being placed on retarding the progression, which currently has a quoted 7.6% retreatment rate using the standard “epi-off” CXL procedure