Dec. 13, 2000 An operation developed at Johns Hopkins to halt blinding retinal damage from age-related macular degeneration (AMD) improved vision in nearly half of the first 100 patients treated, according to a recent report in the American Journal of Ophthalmology.
"Six months after surgery, 48 percent of our patients could read an additional two lines on a standard eye chart or had vision of 20/100 or better -- enough to legally drive in the state of Maryland -- and 16 percent could read an additional six lines on the eye chart," says Eugene de Juan, M.D., professor of ophthalmology at Hopkins' Wilmer Eye Institute. "No other treatment for AMD comes even close to that. These are the best results ever recorded."
The operation, macular translocation, moves the central, most light-sensitive part of the retina away from an overgrowth of abnormal blood vessels that bleed and damage retinal tissue. The procedure is useful only for people newly diagnosed with this so-called wet form of AMD. AMD is the major cause of blindness in people age 55 and older.
In the surgery, de Juan pinches the sclera, the white, outer skin of the eyeball, as if it were a hollow rubber ball, then puts sutures into the side wall of the eye to keep it pinched, shortening its length. This buckles the retina, which lines the inner wall of the eyeball. De Juan next injects a salty solution into the eye under the retina, causing the retina to "blister" enough to be moved slightly without detaching it. The average distance the retina must be moved is only about 0.3 to 0.4 millimeters -- about .01 inches.
The report, published in the October issue of the journal, chronicles results of the procedure in 102 eyes in the first 101 consecutive patients. Patients ranged in age from 41 to 89; 60 percent were male. Within three months following surgery, 37 percent of the patients gained two or more lines of vision on a standard eye chart compared to measurements taken before surgery. Within six months following surgery, 48 percent of patients experienced similar vision improvement, and 10 percent had vision better than 20/40.
Patients with worse preoperative vision or who developed complications, most commonly retinal detachment, did not improve.
Other treatments for AMD include laser photocoagulation and photodynamic therapy (PDT). In the first, a laser beam is used to destroy abnormal blood vessels, but few patients maintain enough central vision to permit reading or driving, and the laser could harm surrounding tissue.
Photodynamic therapy combines the use of a light-sensitive medication and a laser light beamed into the eye. The laser is too weak by itself to have any effect on the retina, but it activates the drug, which produces a toxic, reactive form of oxygen that can damage the diseased tissue and blood vessels while leaving healthy cells alone. PDT can't restore vision, but it can halt the progression of the disease. De Juan says the fix is temporary, and some patients who receive PDT need surgery later.
De Juan stresses the importance of early management of AMD: "Macular translocation is effective only for people just diagnosed. Once they've had the disease for a few months, it may be too late." To date, he has performed close to 400 of the operations.
The study's other authors were Dante J. Pieramici, M.D.; G.Y. Fujii; S.M. Reynolds; M. Melia; Mark S. Humayun, M.D., Ph.D.; Andrew P. Schachat, M.D.; and Craig D. Hartranft, M.D.
Related Web sites: Wilmer Eye Institute at Johns Hopkins http://www.wilmer.jhu.edu
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