Eyeworld

MAR 2012

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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78 EW CORNEA March 2012 Treating pterygium recurrences by Michelle Dalton EyeWorld Contributing Editor Pterygia, pre-op Source: McDonald Eye Associates Addressing secondary pterygium is usually dependent upon how the initial surgery was performed P terygium recurrence is fairly common in the south, and rates have been reported from 24-89%, de- pending upon the original technique used to excise the ptery- gium. When recurrences happened 20 years ago, "we'd use a mucous membrane graft from inside of the lip. If we used the conjunctiva from the upper temporal quadrant, we thought we might affect muscles or cause scarring or a muscle imbal- ance," said Stephen A.D. Schuster, M.D., Schuster Eye Center, El Paso, Texas. These days, recurrences are much more likely to be treated via conjunctival autograft or amniotic membrane graft, with or without mitomycin C (MMC). One novel treatment—subconjunctival injec- tions of bevacizumab (Avastin, Genentech, South San Francisco, Calif.)—is beginning to gain some attention as well. Referral patients with recurrent pterygia usually had "bare scleral or sliding graft initially, where the ep- ithelium is opened and then closed with a micro-suture," said Rick Palmon, M.D., partner, Southwest Florida Eye Care, Fort Myers, Fla. "I think the free graft is crucial to pre- venting recurrence." When he practiced in the deeper south, J.E. "Jay" McDonald II, M.D., would freeze the pterygium and "only had one person who con- tinued to recur." Pterygia, pre-op, crossing onto the cornea Source: McDonald Eye Associates Although pterygia are a corneal degeneration, Dr. McDonald, McDonald Eye, Fayetteville, Ark., said "because so many of them are aggressive even over the sclera, I have had a hard time in my mind classifying them as such." Dr. Palmon treats primary exci- sion with conjunctival autografts, as he's found the amniotic membrane grafts can lead to more instances of recurrence. He said the amniotic graft dissolves slowly over a few weeks, but too quickly to block or prevent tissue from growing. About 15 years ago, the general consensus was grafting was the best option for recurrence, Dr. Schuster said. "For years, my approach was to take conjunctiva from the upper quadrant, remove the pterygium, re- move the underlying fibrous tissue, and then suture the graft in place," he said, estimating his recurrence rate was "probably cut to 10%." "If you suture or glue the graft, it doesn't make much difference as far as the ultimate outcome is con- cerned," he said. Initial treatment Knowing how the primary ptery- gium was treated will determine the course of treatment for the recur- rence, Dr. Palmon said. He tries to treat recurrence medically—gener- ally with a topical steroid—before considering additional surgery. "If the recurrence is really in- flamed, I'll also give a subconjuncti- val injection of 5-fluorouracil 0.1 cc to calm the pterygium down, and that's usually enough to prepare the eye for any repeat surgical incision," he said. "I'm a firm believer in using Example of a patient referred in for recurrence after primary bare scleral excision Source: Rick Palmon, M.D. prophylaxis with MMC for recur- rences." After excising the ptery- gium and any Tenon's fascia, he places MMC beneath the adjacent conjunctiva, but not on the sclera itself. He uses 0.2 mg/mL for about 1-2 minutes, depending on the severity of the recurrence. He advises surgeons to ensure they've covered the sclera—leaving it bare results in a "much higher risk of scleral thin- ning and scleral melting." Dr. Schuster will treat a recur- rence as soon as he sees it on the conjunctiva but before it reaches the cornea. Dellen—although rare post- MMC—can happen, "which is why we need to be cautious about using the antimetabolites in general." Dr. McDonald uses a technique first described by Eric D. Donnenfeld, M.D., where the pterygium is injected 1 month before excision and no MMC is placed directly on the corneal bed. If the patient received a con- junctival autograft for the primary pterygium, Dr. Palmon will use an amniotic membrane graft for the re- currence; if the patient received MMC or beta radiation for the pri- mary pterygium, "there's an in- creased risk of inducing later onset scleral thinning or melting" if used on the recurrence. In the post- radiation patient, he will avoid antimetabolites altogether during the recurrence treatment. "I've become even more conser- vative over the past 10 years. If the pterygium isn't bothering the pa- tient, if it's about 2 mm onto the cornea, it appears quiet, and the pa- tient is 50 or 60 years old, I just leave it alone," Dr. Schuster said. "The reason there are so many approaches to treating these is that no one has the perfect answer," Dr. McDonald said. Treatment advances The use of Avastin is starting to gain some popularity, but it's a mixed bag, Dr. Palmon said, with some re- ports showing "a decrease in the corneal vessels, but the amount of decrease is so clinically insignificant that it didn't make a difference in the size of the pterygium." The best potential use for Avastin may be in cases where the pterygium has not yet recurred, but is at its beginning phase. "I think Avastin's got tremen- dous potential," Dr. Schuster said. "If the graft is taking well, but small vessels are beginning to grow in the conjunctiva encroaching on the su- tured graft, that's the time I'd be more likely to give an Avastin injection," he said. The promise of Avastin is that it could be as effective as MMC and should not be toxic to the endothe- lium, Dr. McDonald said. He plans on advocating its use on the next re- current case he sees. "I have been trying to figure out pterygium for 30 years. I think this drug will definitely help," Dr. McDonald said. EW Editors' note: The doctors mentioned have no financial interests related to this article. Contact information McDonald: 479-521-2555, mcdonaldje@mcdonaldeye.com Palmon: 239-768-0006, rpalmon@swfleye.com Schuster: 915-533-3461

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