EyeWorld Asia-Pacific June 2020 Issue

44 EWAP JUNE 2020 CORNEA E pithelial thickness mapping is known for its ability to help detect corneal disease, including keratoconus. However, it also can assist with treatment and enhancement decisions for LASIK and PRK, according to ophthalmologists who are using it. “I think we’re just learning how to use this powerful technology,” said Lance Kugler, MD. “It has taught me how critical the epithelium is to our visual system. The ability to measure it gives us a valuable tool for our treatment decisions.” to selecting transepithelial PRK to epithelial debridement in iÞià ܈̅“>« `œÌ w˜}iÀ«Àˆ˜Ì dystrophy,” said Kerry Assil, MD. His work with epithelial mapping with the SPECTRALIS OCT (Heidelberg Engineering) adapted for the anterior segment analyzes epithelial thickness, patterns, and remodeling over time. What’s considered abnormal When reviewing epithelial maps, ophthalmologists using them must keep in mind what’s >˜` ˆ˜ÃÕvwVˆi˜Ì LÕvviÀˆ˜} œv «ÀˆœÀ scars. The latter may include apical epithelial hypoplasia coupled with surrounding hypertrophy, he said. Something additional that Dr. Kugler considers is the bilaterality of the results. “The two eyes should look the same. v ޜՅ>Ûi Èä ù“ ˆ˜ œ˜i iÞi and 30 in the other, you know one eye is not normal. Fifty microns is the norm, but some people are thicker or thinner,” he said. Guiding treatment 10 years later Ophthalmologists interviewed by EyeWorld considered how they would handle a patient who was 10 years post-LASIK and had a normal epithelial thickness. Based on what they saw with epithelial thickness mapping, ܜՏ` ̅iÞ ÌÀi>Ì ÜˆÌ…y>« relifting and laser or use PRK? “Since the advent of the femtosecond laser, eyes 10 years post-LASIK are no longer >“i˜>Li ̜ ÀœṎ˜i y>« Àiˆv̈˜}] `Õi ̜ wÀ“ >`…iÀi˜Vi]» À° Assil said. “While nearly all post-myopic PRK and LASIK eyes demonstrate some degree of epithelial hypertrophy, the observation of an unusually large degree of hypertrophy might make a relift more appealing.” This can help avoid ºÀiÅÕvyˆ˜} ̅i `iVŽ]» >à Dr. Assil described it. œÌ…*, >˜` y>« Àiˆv̈˜} >Ài reasonable, Dr. Kugler thinks. If choosing PRK, make sure to consider how much epithelial thickness there is. AT A GLANCE • Epithelial thickness mapping has a role in guiding treatment and enhancement decisions related to LASIK and PRK. It also helps with patient education. • Mapping can help surgeons decide what sort of treatment may be used post-refractive surgery, even several years later. • Understanding of the use of epithelial mapping with refractive surgery patients will continue to grow. Contact information Assil: kerry@assileye.com Chu: yrchu@chuvision.com Kugler: lkugler@kuglervision.com This article originally appeared in the April 2020 issue of EyeWorld . It has been UNKIJVN[ OQFKƂGF CPF CRRGCTU JGTG YKVJ permission from the ASCRS Ophthalmic Services Corp. Using epithelial mapping for LASIK, PRK, and refractive enhancement by Vanessa Caceres Contributing Writer Epithelial thickness map of a normal, healthy cornea. Epithelial thickness map of an eye with keratoconus; the epithelium has thinned over the area of ectasia. Source (all): Jessica Heckman, OD Dr. Kugler uses epithelial mapping with the Avanti OCT system (Optovue) with every new patient consultation, be it for LASIK, PRK, or even cataract surgery. After refractive surgery, Dr. Kugler and staff will obtain mapping and also do so on a case-by-case basis with IOL patients. This helps them to track progression of the maps over time. “Understanding the epithelial distribution can improve clinical decisions, ranging from time of LASIK or PRK enhancement outside of the norm. “A normal i«ˆÌ…iˆ> ̅ˆVŽ˜iÃà ˆÃ xä ù“] but what OCT gives us is a pattern and an overview of thickness over a larger area of the cornea,” said Y. Ralph Chu, MD. “This pattern can help determine areas of relative thinner or thicker epithelium, which can be helpful in detecting abnormal curvatures of the cornea.” Abnormalities that Dr. Assil considers include unusually hypertrophic central epithelium, variably irregular distribution, continued on page 49