Eyeworld Daily News

27 EW SHOW DAILY ASCRS•ASOA Symposium & Congress, Los Angeles 2017 by Lauren Lipuma EyeWorld Contributing Writer Update on refractive surgery in the military who had a high PTA as compared to those with high ectasia risk scores or low residual stromal bed thick- ness. When a patient's topography is normal, PTA has been shown to be the most robust risk factor for ectasia, but a low PTA value does not mean ectasia will not occur, he said. For this reason, Dr. Townley does not think PTA should be included in patient screening criteria. Captain Elizabeth Hofmeister, MD, San Diego, compared outcomes of wavefront-guided versus wave- front-optimized LASIK for correct- ing myopia in military patients. The prospective, randomized study aimed to quantify the predictability of refractive outcomes, quality of vi- sion, and patient-reported outcomes with the two procedures. The study found that both procedures gave patients excellent visual results. Patients had roughly equal reports of glare and haloes after surgery, and results were ba- sically equivalent when looking at the entire range of refractive errors treated. However, a higher percentage of patients achieved "super vision" of 20/16 or 20/12 after surgery with the wavefront-guided procedure. Using a vector analysis of sphere and cyl- inder outcomes in the two patient groups, Dr. Hofmeister discovered that the wavefront-guided platform was more predictable when correct- ing 1 D or less of astigmatism. This advantage gave patients slightly bet- ter visual acuity, increased patient satisfaction with their vision, and induced fewer higher order aberra- tions, Dr. Hofmeister said. EW Editors' note: The speakers have no financial interests related to their comments. T his year's Military Refrac- tive Surgery Symposium featured presentations on managing ocular surface disease in military refrac- tive patients, updates on screening standards for refractive surgery candidates, the role of small incision lenticule extraction (SMILE) in the Department of Defense, and more. Major Bryan Chin Hou Ang, MBBS, Singapore, described the results of a study on corneal haze and endothelial cell loss after PRK in the Singapore Armed Forces. Singapore has one of the highest rates of myopia in the world—nearly 82% of young Singaporean males are myopic—and PRK is a valuable tool used by the Singapore Armed Forces to optimize the visual performance of servicemen, Dr. Ang said. PRK has the potential to in- duce corneal haze and endothelial damage, but few large studies have examined these outcomes in Asian populations. Dr. Ang's retrospective study characterized refractive out- comes, corneal haze, and endothe- lial cell loss 12 months after PRK in members of the Singapore Armed Forces. The study found that myopia and astigmatism were associated with increased corneal haze af- ter PRK, and younger age may be associated with early corneal haze, but this effect is lost at 12 months. The results also suggested PRK may accelerate endothelial cell loss, but this effect does not appear to be in- fluenced by the use of mitomycin-C, Dr. Ang said. Major Richard Townley III, MD, San Antonio, addressed wheth- er percent tissue ablated should be part of the screening criteria used to evaluate for military refractive surgery candidates. Percent tissue ablated (PTA) is defined as the amount of tissue al- tered divided by the patient's central corneal thickness. Dr. Townley cited a 2014 study that found the odds ratio of experiencing post-refrac- tive ectasia was greatest in patients Visit NIDEK Booth #447 Visit NIDEK Booth #447 CEM-530 SPECULAR MICROSCOPE CEM-530 SPECULAR MICROSCOPE Dr. Ang describes the results of a study on corneal haze and endothelial cell loss after PRK in the Singapore Armed Forces.

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