Age-Related Macular Degeneration Treatment with Photodynamic Therapy
An option for treating neovascular AMD is photodynamic therapy, approved by the U.S. Food and Drug Administration (FDA) in 2000. The procedure is particularly helpful for people who have neovascularization directly under the fovea. After FDA approval, photodynamic therapy largely replaced photocoagulation for revascularization of AMD under the foveal center.
Photodynamic therapy is a two-step procedure performed in a doctor's office. It involves injecting a light-sensitive drug called verteporfin (Visudyne) into the bloodstream. The drug has a preference for binding to cells in the new blood vessels. The doctor beams a low-powered laser into the eye to activate the drug in the location of the abnormal blood vessels. This photochemical process leads to closure of the "bad" blood vessels without direct injury to the retinal tissue that a thermal laser causes. As a result, growth of abnormal vessels stops, and vision loss is stabilized with minimal damage to the retina.
In randomized, controlled trials led by researchers at Johns Hopkins, 402 patients with neovascularization received photodynamic therapy and 207 received placebo therapy. After two years of treatment, 53 percent of the people in the photodynamic group avoided additional moderate vision loss, compared with 38 percent of participants in the placebo group. In the third year, further vision loss in the photodynamic group was minimal, particularly in people with predominantly classic neovascularization.
Adverse side effects of photodynamic therapy included pain, swelling, hemorrhage, and inflammation at the injection site. About 1 percent of the participants had photosensitivity reactions.