New Therapy Helps Treat Form of Macular Degeneration

A new treatment called photodynamic therapy (PDT) might help more than 200,000 people who are afflicted each year with a form of macular degeneration, a progressive disorder that causes gradual loss of central vision.

"Photodynamic therapy helps patients with the `wet' form and is a valuable new treatment for this type of macular degeneration," says Dr. William Mieler, a professor of ophthalmology at the McPherson Retina Center at Baylor College of Medicine and a participant in a national PDT clinical trial.

This disease, which primarily affects people over age 60, comes in two forms: wet and dry. The `dry' form involves the wasting away of tissue beneath the retina. Currently, there is no effective treatment. The `wet' form implies blood vessel growth with leakage under the retina. In the past, this form could only be treated with a laser or surgery.

During photodynamic therapy, the drug verteporfin (also known as Visudyne) is injected into a vein in the arm. The drug is localized in tissues that have active blood vessel growth. After about 15 minutes, a low-energy laser is used on the front part of the eye.

"By combining the laser and the drug, we are better able to target the troubled area without causing any significant damage to other parts of the eye," Dr. Mieler says.

Patients who took part in a clinical trial at Baylor showed improvement in their symptoms. Most had a slight degree of vision loss over the two-year study. However, the rate of loss would have been much greater had they not received treatment.

"This treatment, which is not for all patients with the `wet' form of the disease, slows the process of macular degeneration, but is not a cure," Dr. Mieler says. "It is however a big step in the treatment regimen."

PDT was recently approved by the Food and Drug Administration (FDA). Drs. Alice McPherson and Eric Holz with the McPherson Retina Center collaborated with Dr. Mieler on the clinical trial.

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©2006 Texas Medical Center

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