November 13 , 2006
Study shows laser treatment does not
prevent vision loss from AMD
BY joy bell
Low-intensity laser treatment, thought to be possibly beneficial in slowing or preventing the loss of vision from age-related macular degeneration, is ineffective in preventing complications of AMD or loss of vision, according to a study published in the November 2006 issue of Ophthalmology.
The findings are a result of a study conducted by Emory University and 21 other clinical sites nationwide. The Complications of Age-Related Macular Degeneration Prevention Trial looked at more than 1,000 people with AMD. The study was supported by grants from the National Eye Institute of the National Institutes of Health.
AMD is the leading cause of vision loss in the United States for people over age 60. Early signs of AMD include the presence of yellowish deposits under the retina, called drusen. Eyes with large drusen are at increased risk of progressing to advanced AMD, with accompanying loss of vision.
First considered in the 1970s, low-intensity laser treatment has been shown to reduce the extent of drusen. However, the studies evaluating the impact of laser treatment on vision have been small, and the results inconsistent.
The study was designed to assess the safety and effectiveness of laser treatment in preventing vision loss among people with large drusen in both eyes. It found there was no difference in vision or in progression to advanced AMD between treated and untreated eyes, which were closely observed for the duration of the trial.
“We’ve known for years that we could use laser treatment to make drusen disappear,” said G. Baker Hubbard, retina specialist at Emory Eye Center. “The real question has been whether or not making drusen disappear translates into long-term improvement of vision and less likelihood of loss of vision. We’ve never known the answer to that question with certainly, and now we do,” he explained. “These results are very important for that reason.”
A total of 1,052 participants over the age of 50 who had 10 or more large drusen and a visual acuity of 20/40 or better in each eye were enrolled through 22 clinical centers. One eye of each participant was treated and the other eye was observed throughout the five years of the trial. After five years, 20.5 percent of the treated eyes and 20.5 percent of the untreated eyes had lost three or more lines of visual acuity on a standard eye chart. Likewise, 20 percent of treated and untreated eyes progressed to advanced AMD. Change in visual acuity was strongly associated
with the development of advanced AMD, but not with treatment group.
“This is an important study because after 35 years of inconsistent results from
preventive laser treatment trials, we now know that this approach does not
seem to stop vision loss from AMD,” said NEI Director Paul Sieving. “Doctors using this technique should reconsider its use in patients with good vision, such as those studied in
At present, the only established way to decrease the risk of vision loss in
people with early AMD is to take daily supplements of vitamins and minerals, Sieving said.
The NEI has launched a new nationwide study to see if a modified combination of vitamins, minerals and fish oil can further slow the progression of vision loss from AMD.