Macular Degeneration
A diagnosis of macular degeneration once meant certain blindness. Today, thanks to a remarkable new laser procedure, it is possible to slow damage caused by a form of the disease and stabilize the patient's vision.
The procedure, called Photo Dynamic Therapy (or PDT), is the latest, most effective treatment for the "wet" form of macular degeneration, which destroys the central vision of up to one in three Americans.
"Until PDT, the only treatments available against macular degeneration had the side effect of retinal scarring," said Dean R. Cummins, M.D., Ph.D., Ophthalmologist and Retinal Specialist with Phelps Memorial Hospital Center, who was a principal investigator for the FDA on the laser treatment. "Earlier lasers slowed damage to blood vessels but caused scarring which impaired vision. PDT offers a significant advance by containing damage without causing retinal scarring."
PDT employs a cold infrared laser and a light-absorbing drug, Visudyne. Once administered, the drug travels through the body, drawn to the abnormal, leaking blood vessels in the eye's macula. The cold laser is then aimed at the damaged blood vessels for 83 seconds. The laser photo-activates the drug, triggering a chemical reaction that destroys the damaged blood vessels and stops the leakage. The entire procedure takes twenty minutes and is painless.
"What makes this treatment remarkable is that, unlike earlier heat-based laser therapies for macular degeneration, PDT does not scar retinal tissue: it destroys the leaking blood vessels but central vision remains intact," said Dr. Cummins.
PDT is FDA approved for the treatment of wet macular degeneration, which affects about 20 percent of patients with the disease and is the leading cause of loss of vision in Americans over the age of 65. A patient typically requires three to four treatments at three-month intervals, at which time the blood vessels are stable, and the improvement is considered permanent. The most common side effect of treatment may be increased light (photo) sensitivity: for three to five days after each treatment, the patient should avoid direct sunlight, keep arms and legs covered, and wear protective sunglasses when outdoors.
According to Dr. Cummins, PDT is most effective in early-stage macular degeneration. "With a newly diagnosed patient we have the greatest chance of preserving vision. In contrast, if symptoms have been present for two years, the goal of treatment would be to contain damage, to preserve what remains of the patient's vision."
Dr. Cummins, who is an attending physician at Phelps and is the director of its Macular Degeneration Treatment Center, completed his residency at Yale Medical School and his retina fellowship at Harvard Medical School. He has been a clinical instructor at Manhattan Eye, Ear and Throat Hospital teaching residents and fellows in the retina clinic. In addition, Dr. Cummins maintains a private practice in Ossining, NY.