Vision Loss Not Prevented by Laser Treatment of Early Macular Degeneration

Wednesday, November 01, 2006

ROCHESTER, Minn. — A research study of more than 1000 patients has provided the first conclusive evidence that laser treatments are "ineffective" in preventing vision loss for sufferers of early age-related macular degeneration. The study results will be published in the November 2006 issue of the journal Ophthalmology. Approximately 50 of the patients were treated at the Mayo Clinic study site.

Mayo Clinic was one of 22 sites nationwide that participated in the research study, which was funded by the National Eye Institute (NEI) of the National Institutes of Health (NIH). Colin McCannel, M.D., a Mayo Clinic eye surgeon and principal investigator of the study at Mayo, says that although laser treatments have been used successfully to treat other eye conditions, the study results have now settled a long-simmering debate over their effectiveness in treating the early stages of macular degeneration.

"For more than 30 years, it has been known that laser treatment alters the appearance of 'dry' macular degeneration: so-called 'drusen,' deposits under the retina that are the first symptom of early age-related macular degeneration, reabsorb when treated with lasers," says Dr. McCannel. "However, there has been extensive debate about whether disappearance of the drusen actually slowed down the progression of the disease or prevented vision loss for patients. The results of this study are clear: vision loss progressed at the same rate whether or not laser treatments were used to alter the drusen."

The laser treatments did not cause any harm, according to Dr. McCannel. "One of the questions posed by the study was whether the use of lasers might cause scarring that would actually lead to faster vision loss." The study confirmed what many ophthalmologists suspected: laser treatments have no effect, good or bad, on the progression of early macular degeneration to the next stages, which lead to vision loss and eventual blindness for many patients. "We can change the appearance of the disease with laser treatments," says Dr. McCannel, "but that does not affect the eventual progression of the disease."

Macular degeneration is an eye condition that is the leading cause of blindness in Americans over age 60. It is believed that most sufferers have a genetic predisposition to develop the disease, but other risk factors such as aging and smoking increase an individual's chance of developing macular degeneration. Researchers are not sure what causes some patients to develop a complication called "wet disease," an overgrowth of blood vessels in the retina, which is the actual cause of vision loss and eventual blindness. The use of laser treatments to remove the abnormal blood vessels has been proven effective in slowing the rate of vision loss for people with wet disease.

"At present, the only established way to decrease the risk of vision loss in people with large drusen (early age-related macular degeneration, or AMD) is to take daily supplements of vitamins and minerals as used in the NEI-supported Age-Related Eye Disease Study (AREDS)," said NEI director Paul A. Sieving, M.D., Ph.D. "This study found that high-dose antioxidant vitamins and minerals (vitamins C and E, beta-carotene, zinc, and copper), taken by mouth by people at risk of developing advanced AMD, reduced the risk of progression to advanced AMD by 25 percent and the risk of moderate vision loss by 19 percent. People at risk for AMD are advised not to smoke and to maintain a healthy lifestyle, with a diet including leafy green vegetables and fish."

Learn more about age-related macular degeneration and its treatment.

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