Eyeworld

EW CORNEA 68 July 2016 by Maxine Lipner EyeWorld Senior Contributing Writer Rapuano, MD, chief of the cornea service, Wills Eye Hospital, Philadel- phia. Common uses "My most common reason to use mitomycin is with excimer laser sur- gery," Dr. Rapuano said, adding that he frequently uses MMC in conjunc- tion with PTK for removing scar tis- sue and also for Salzmann's nodular degeneration. For excimer laser PRK patients, he finds that MMC decreas- es the chances of haze and scarring. Dr. Rapuano uses 0.02% MMC on an 8 mm sponge for 60 seconds 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 recur- rence rates of problems like pteryg- ium, according to Christopher J. Harnessing mighty mitomycin-C Ischemia of the sclera after MMC use in pterygium surgery when used in conjunction with PTK. "Then I wash it off with 30 ccs of sa- line," 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 re- currences. "I won't use it unless I'm treating recurrent pterygium that has already had a conjunctival auto- graft," he said. "For those, I put the same concentration on a Weck-Cel sponge [Beaver-Visitec International, Waltham, Massachusetts] under- neath the conjunctiva, and I try not to get it on the bare sclera under the conjunctiva." He usually leaves this for a minute or 2, 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 prima- ry pterygium surgery. Even with recurrent cases, Dr. Lee is selective in his MMC usage. He is wary of the potentially devastating complica- tions, 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 re- ported even decades after the initial surgery," Dr. Lee said, adding that the melts, however, are usually asso- ciated with the pterygium surgery, which is why he avoids this usage in most cases. Dr. Lee does, however, routinely rely on MMC for PRK cases. Here he uses a concentration of 0.02% for 12 seconds following the laser treatment and prior to bandage lens placement. "I also use mitomycin at the same concentration when removing Salzmann's nodules after a superficial keratectomy with appli- cation for 30 seconds via a sponge soaked in MMC," he said. MMC pearls When removing the MMC, Dr. Lee recommends using 2 bottles of balanced salt solution after the time allotted for washing this off the oc- ular surface. "If using for pterygium surgery, it should never be applied to bare sclera," he said. Pharmaceutical focus

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