Treating Macular Degeneration

There is currently no cure for AMD, but there are treatments that can slow the progression of the disease and preserve some sight. Several options are available. This section contains more information on:

• High-dose combination of vitamins
• Laser photocoagulation
• Photodynamic laser
• Drugs
• Treatments under study

High-Dose Combination of Vitamins

People with intermediate dry AMD may be able to slow the progression of the disease by taking a high-dose combination of vitamin C, vitamin E, beta carotene, zinc, and copper. According to a 10-year-long study sponsored by the National Eye Institute, the vitamins, if taken on a daily basis, can reduce the risk of losing vision by about 25 percent. The study examined the effect of 500 milligrams of vitamin C, 400 international units of vitamin E, 15 milligrams of beta carotene, and 80 milligrams of zinc as zinc oxide. (Trace amounts of copper were added to avoid zinc-induced copper-deficiency anemia.) A small number of brands of pills containing a combination of these substances are available; they should be used in consultation with your doctor.

Laser Photocoagulation

To stop the abnormal growth of blood vessels characteristic of wet AMD, the physician aims a laser beam at the vessels to cauterize them, stopping their growth and preventing further leakage. Because this treatment also damages surrounding tissue, it is not used to treat blood vessels beneath the center of the macula. While laser treatment may delay further vision loss, abnormal vessel growth is likely to resume at some point, and vision already lost will not be restored. The treatment is performed on an outpatient basis; the patient is awake, and the eye is numbed with local anesthetic in the form of eyedrops. More than one treatment may be needed.

Photodynamic Therapy

A special kind of laser therapy can stop leakage from abnormal blood vessels growing under the retina in cases of wet AMD, thus slowing the rate of vision loss, with much less damage to surrounding tissues than conventional laser therapy. The therapy uses the intravenous injection of a light-sensitive dye called verteporfin (Visudyne), which circulates through the bloodstream and, when activated by a laser, sticks to the inside surfaces of the new blood vessels to shrink them and stop leakage. The treatment is repeated three to five times over one to two years to stop the leaking.

Photodynamic therapy will not guarantee that abnormal vessel growth will stop for good. But it prevents additional vision loss in about 65 percent of patients and brings about some improvement in the vision of about 15 percent.

Drugs to Stop Blood Vessel Growth

Wet AMD can be treated by injecting a drug that inhibits the growth of new blood vessels into the center portion of the eye. The drug blocks a protein called vascular endothelial growth factor, or VEGF, that promotes the growth of new blood vessels.

Two anti-VEGF drugs have been approved by the Food and Drug Administration to treat wet AMD. Both of these drugs, pegaptanib (Macugen) and ranibizumab (Lucentis), are injected into the jellylike central part of the eye and have been shown to slow the progression of the disease. These drugs have also been shown to reverse some of the effects of the disease. As many as 35 percent of patients who receive a monthly injection of ranibizumab, for example, experience improvements in their vision. Although pegaptanib has an advantage of somewhat less frequent dosing, it appears to be less effective for improving vision. The two drugs have not been directly compared.

Treatments Under Study

Researchers are studying several new treatments for wet AMD that are currently considered experimental.

A surgical procedure called macular translocation may be an option when the growth of abnormal blood vessels and fluid leakage are happening directly under the center of the macula, where a laser beam cannot safely be directed. The surgeon partly detaches the retina, leaving intact connections to the optic nerve, and rotates it very slightly so the macula is moved over healthy tissue. A bubble of air is injected into the eye to hold the retina in place while it heals. The light-sensing rods and cones of the macula may function better in the healthier position, and laser therapy can be used to destroy the previously covered blood vessels.

Research is also being done on additional anti-VEGF drugs and on anecortave acetate (Retaane), which also blocks the growth of new blood vessels but is injected behind the eye rather than into the eyeball.