EyeWorld Asia-Pacific September 2016 Issue

62 EWAP cornea September 2016 Two scleral melts after pterygium surgery with MMC Source (all): W. Barry Lee, MD by Maxine Lipner EyeWorld Senior Contributing Writer Harnessing mighty mitomycin-C Using the compound successfully in corneal procedures F rom excimer laser surgery to Salzmann’s nodular degeneration, practitioners often reach for mitomycin-C (MMC) to help ensure corneal procedure success. They find this potent compound can help to prevent scarring, haze, and recurrence rates of problems like pterygium, according to Christopher J. Rapuano, MD , chief of the cornea service, Wills Eye Hospital, Philadelphia. Common uses “My most common reason to use mitomycin is with excimer laser surgery,” Dr. Rapuano said, adding that he frequently uses MMC in conjunction with PTK for removing scar tissue and also for Salzmann’s nodular degeneration. For excimer laser PRK patients, he finds that MMC decreases the chances of haze and scarring. Dr. Rapuano uses 0.02% MMC on an 8 mm sponge for 60 seconds when used in conjunction with PTK. “Then I wash it off with 30 ccs of saline,” he said. When using the MMC for PRK patients, he applies the same concentration of 0.02% on the same 8 mm sponge, but typically only for 12 seconds, unless the patient had previously undergone RK. In such cases, he finds these patients, who have a slightly higher chance of scarring, do better if the MMC is left on the surface for 30 seconds. In cases of pterygium surgery, Dr. Rapuano reserves MMC for recurrences. “I won’t use it unless I’m treating recurrent pterygium Ischemia of the sclera after MMC use in pterygium surgery that has already had a conjunctival autograft,” he said. “For those, I put the same concentration on a Weck-Cel sponge [Beaver- Visitec International, Waltham, Massachusetts] underneath the conjunctiva, and I try not to get it on the bare sclera under the conjunctiva.” He usually leaves this for a minute or two, based on the individual patient. “Depending on how much scarring there is on the cornea, I may or may not put it on the cornea for 60 seconds,” he said. The hope is that it will decrease the amount of corneal scarring. Likewise, W. Barry Lee, MD , Eye Consultants of Atlanta, and medical director, Georgia Eye Bank, does not use mitomycin for primary pterygium surgery. Even with recurrent cases, Dr. Lee is selective in his MMC usage. He is wary of the potentially devastating complications, including scleral stromalysis. In a study that he took part in, investigators found this may occur anywhere from months to years after application. In the study, 31% of patients ultimately needed scleral patch grafts. 1 He finds that pterygium surgery complications with MMC tend to be the most publicized, but there can be complications when using mitomycin for other procedures as well. “Scleral melts, necrotizing scleritis, infectious ulcers, and frank scleral perforations have been reported even decades after the initial surgery,” Dr. Lee said, adding that the melts, however, are usually associated with the pterygium surgery, which is why he avoids this usage in most cases. Dr. Lee does, however, routinely rely on MMC for PRK