Eyeworld

177 April 2016 EW MEETING REPORTER study showed similar results in both groups. "However, in the flap lift en- hancement, there can be epithelial ingrowth," he said. Meanwhile, with PRK over the LASIK flap, there may be some haze. The good thing about the LASIK enhancement is that if you lift the flap, in theory, you can lift it an indefinite number of times, Dr. Chang said. When using PRK over the LASIK flap, you can recut, but Dr. Chang prefers a flap lift. Editors' note: Dr. Frueh has no related financial interests. Refractive surgery after previous corneal surgery A symposium on refractive surgery after previous corneal surgery fo- cused on laser reoperations, corneal grafts, and other topics. Ioannis Pallikaris, MD, Crete, Greece, and Yeong-Fong Chen, MD, Taipei, Tai- wan, served as chairs of the session. John Chang, MD, Hong Kong, spoke about photorefractive keratec- tomy (PRK) over LASIK, specifically in reoperations. An International Society of Refractive Surgery sur- vey from 2015 looked at trends in refractive surgery, he said, and it was found that the most common procedure is still LASIK. Dr. Chang highlighted some of the advantages and disadvantages of using PRK. "The advantage of PRK is that it avoids complications associated with the flap," he said. PRK also preserves more corneal tissue, which makes it a good choice for thinner corneas. There may also be less dry eye and less risk of ectasia with this procedure. Additionally, PRK may be a better option for corneas with scarring or epithelial basement membrane disease. Dr. Chang added that there are, however, still some disadvantages associated with PRK. "There is more pain and discomfort for a few days," he said. There is longer healing time associated with PRK, as well as corneal haze and a higher infection rate. Mitomycin-C (MMC) is rou- tinely used with PRK, he said, and visual outcomes with MMC and PRK are similar or better than without MMC. Additionally, use of MMC helps to reduce haze formation. The standard routine dosage typically used is 0.02%, Dr. Chang said, and this is applied for between 30 and 60 seconds, depending on how strong the patient's myopia is. MMC can reduce haze with a dosage as low as 0.02% used for as little time as 12 seconds, he said. Dr. Chang also detailed a number of studies looking at use of MMC, infection rates, and comparison between PRK and LASIK. Dr. Chang then delved into preferences for using either PRK or LASIK after certain previous corneal surgeries. Post-radial keratotomy (RK) surgery, he suggested doing microkeratome LASIK first. If there is regression after the first post-RK LASIK, he suggested that PRK with MMC on the flap may be a good choice because it may be very diffi- cult to lift the flap after this. Dr. Chang discussed a study that compared using flap lift enhance- ment vs. PRK over the LASIK flap after a LASIK procedure, and the Dr. Chang discussed the best choice after a successful corneal graft. Spectacles or hard contact lenses are the first choice, he said, followed by PRK with MMC or LASIK. A surgeon could also use phakic and pseudophakic piggy- back IOLs, he said. However, there are some concerns of using LASIK after a corneal graft, Dr. Chang said. Innovative trifocal technology When freedom becomes reality FINE TECHNOLOGY by PhysIOL [NEAR] [INTERMEDIATE] [FAR] Beyond the limits of vision ASCRS New Orleans - BOOTH #2811 www.physiol.eu continued on page 178

• Cover