Jul 5 2007
According to a study that appears in the November 2006 issue of the journal Ophthalmology, researchers at the University of Pennsylvania School of Medicine and 21 other clinical centers have found that low-intensity laser treatment - thought to be potentially beneficial in slowing or preventing the loss of vision from age-related macular degeneration (AMD) - is ineffective in preventing complications of AMD or vision loss.
This is the major conclusion of the Complications of Age-Related Macular Degeneration Prevention Trial (CAPT) -a research study supported by grants from the National Eye Institute (NEI) of the National Institutes of Health (NIH).
According to the NEI, AMD is a disease associated with aging that gradually destroys sharp, central vision. Central vision is needed for seeing objects clearly and for common daily tasks such as reading and driving. People with early AMD have drusen - yellow deposits under the retina. The presence of drusen is the first sign of early AMD, and eyes with large drusen are at an increased risk of progressing to advanced AMD, with accompanying loss of vision.
"For the past 35 years, ophthalmologists have wondered about the advisability of employing preventive laser treatment for patients with large drusen who are at a high risk for vision loss and AMD," said Stuart L. Fine, MD, CAPT chairman and chair, Penn's Department of Ophthalmology; Director, Scheie Eye Institute. "We found that laser treatment had neither a clinically significant beneficial nor harmful effect for these patients. There is no evidence from this trial to suggest that people with large drusen should seek preventive laser treatment."
This was the first large-scale, multicenter study to evaluate the efficacy and safety of this technique. The study followed 1,042 participants over the age of 50 (average age of 71) who had 10 or more large drusen and visual acuity of 20/40 or better in each eye. One eye of each participant was treated, while the other eye was observed throughout the five years of the trial. After five years, 20.5% of the treated eyes and 20.5% of the untreated eyes had lost three or more lines of visual acuity on a standard eye chart.
Currently, the only established way to decrease the risk of vision loss in people with large drusen is daily supplements of vitamins and minerals. The NEI-sponsored Age-Related Eye Diseases Study (AREDS) reported in 2001 that a formulation which includes anti-oxidant vitamins (beta-carotene, Vitamin C and Vitamin E) and appropriate doses of zinc and copper could reduce the relative risk of progression from early to late AMD by 25% and reduce the relative risk of vision loss by 19%. The NEI recently launched AREDS2 to see if a modified combination of vitamins, minerals, and fish oil can further slow the progression of vision loss for AMD.