EyeWorld Asia-Pacific September 2020 Issue

REFRACTIVE 36 EWAP SEPTEMBER 2020 advantage over LASIK in terms of the structural preservation, and we know from the way it works it should be an advantage for most patients to not cut through those anterior structures,” Dr. Dupps said, adding that this is true in simulations as well. He went on to say that ectasia risk is also lower with PRK. “There is something about this tapered profile that’s done at the surface of the cornea that I think is friendlier from a structural standpoint vs. a flap that is being cut straight down through a lot of fibers and then you have the ablation,” Dr. Dupps said. “I have a higher percentage of PRK in my practice compared to some people. It’s about 35%.” Dr. Dupps described a software program in testing called SpecifEye (not commercially available) that runs patient-specific simulations of the various refractive surgery procedures, giving a report on the stresses and strains, structural risk metric, and a refractive outcome. Dr. Dupps said there has been an evolution in corneal imaging technologies. Fifteen years ago, he said, tomography was not the standard of care; most refractive surgery screening at that time included topography and ultrasound pachymetry at the center of the cornea. A decade ago, tomography took its place as the standard of care and anterior OCT has more recently become a thing, Dr. Dupps said. “I think most young doctors won’t have been exposed to the epithelial mapping feature and how helpful that can be,” Dr. Dupps said. While Dr. Dupps acknowledged that he has access to a range of available— and some not yet available— technologies to screen for refractive surgery, he stressed the importance of solid tomography, if little else. It’s important to learn how to use it, mostly by learning what normal, slightly abnormal, and frankly abnormal maps look like. “The more cases you look at and see how people have interpreted those, the more comfortable you are going to be assessing new patients,” he said. “The other thing I would say is … when someone sets up the device, make sure you are there. … Some of these features you have to understand yourself to teach techs how to use them.” EWAP References 1. Schallhorn JM, et al. Distinguishing between contact lens warpage and ectasia: usefulness of optical coherence tomography epithelial thickness mapping. J Cataract Refract Surg. 2017;43:60–66. 2. Moshirfar M, et al. Advances in biomechanical parameters for screening of refractive surgery candidates: A review of the literature, Part III. Med Hypothesis Discov Innov Ophthalmol. 2019;8:219–240. Editors’ note: Dr. Dupps is professor of ophthalmology, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio, and has interests with Alcon, Carl Zeiss Meditec, CorneaGen, and Glaukos. Dr. Huang is the Martha and Eddie Peterson Professor of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, and has relevant interests with Optovue. www.apacrs-snec2021.org Supported by: College of Ophthalmologists, Academy of Medicine, Singapore IMPORTANT DATES 29 October 2020 Online Abstract Submission and Registration Reopen 29 April 2021 Deadline for 1st tier Early Bird Registration 29–31 July 2021 Singapore biomechanical measurements can overlap between normal and keratoconic eyes and thus may not be the most reliable in detecting keratoconus. As such, he said he doesn’t use technologies that measure corneal biomechanics. When asked about the different refractive procedures and their impact on corneal biomechanics, both Drs. Huang and Dupps said PRK and SMILE have a lesser effect on corneal biomechanical stability. “SMILE I think carries some