| Emory Report | Volume 52, No. 31 |
FDA green lights new laser vision treatment By Holly Korschun The Food and Drug Administration recently approved a vision treatment known as photodynamic therapy (PDT), which means Emory Eye Center can now offer new hope to patients with a form of age-related macular degeneration (AMD), the leading cause of blindness in Americans over age 50. AMD affects more than a quarter of all Americans over 75, and no one knows what causes the disorder or how to prevent it. The condition affects the central part of the retina, the macula, which is the area of sharpest sight and the part used for reading and central vision. The "wet" or exudative form of AMD--the most blinding form--results when abnormal blood vessels take shape, leaking fluid and blood underneath the retina into a region of the eye called the choroid. The choroid's blood vessels, combined with tissue, can form a scar-like membrane under the retina and block central vision. PDT is significant because there is no cure for wet AMD, and the most widely available treatment--photocoagulation therapy with a heating laser--can cause blind spots and can only be used for about 10 percent of patients with the disease. About 40 to 60 percent of the estimated 200,000 patients diagnosed each year with wet AMD may be eligible for PDT. "It is a promising alternative to the growing number of treatments we now can offer macular degeneration patients. The therapy appears to be safer [and] with fewer risks than photocoagulation therapy," said Paul Sternberg, director of the retina section at the Emory Eye Center. The goal of PDT is to seal leaking blood vessels and slow or stop the progression of vision loss. During PDT, the patient receives an injection of a photosensitizer drug that concentrates in the abnormal choroid blood vessels. A nonthermal laser light shone onto the retina activates the drug. The procedure is performed on an outpatient basis, and patients can return to normal activities immediately, though they will need to stay out of direct sunlight for at least 24 hours. Most need repeat treatments later to enhance results. Following treatments, patients sometimes will experience a temporary reduction of vision, which will improve over the following few weeks. Research shows that the therapy preserves or improves vision in 38 percent of patients and slows vision loss in another 31 percent. The Eye Center was one of about 30 centers worldwide that participated in Phase III clinical trials carried out by CIBA Vision of Atlanta.
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