Low-intensity laser treatment, thought to be possibly beneficial in slowing or preventing the loss of vision from age-related macular degeneration (AMD), is ineffective in preventing complications of AMD or loss of vision, according to a study published in the November 2006 journal/ Ophthalmology/.
The findings are a result of a study conducted by Emory University and 21 other clinical sites nationwide. The study, called the Complications of Age-Related Macular Degeneration Prevention Trial (CAPT), looked at more than 1,000 people with AMD. The study was supported by grants from the National Eye Institute (NEI) of the National Institutes of Health (NIH).
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.
This 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," says G. Baker Hubbard, MD, 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 explains. "These results are very important for that reason."
NEI director Paul A. Sieving, M.D., Ph.D., says, "AMD is the leading cause of vision loss in the United States for people over age 60. 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. Doctors using this technique should reconsider its use in patients with good vision, such as those studied in this trial.
"At present, the only established way to decrease the risk of vision loss in people with large drusen (early AMD) is to take daily supplements of vitamins and minerals as used in the NEI-supported Age-Related Eye Disease Study (AREDS)," Sieving continues. "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."
A total of 1,052 participants over the age of 50 (average age of 71) 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.
The NEI has just 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. This study, called the Age-Related Eye Disease Study 2 (AREDS2), will build upon results from the earlier AREDS study. # # #
The National Eye Institute (NEI) is part of the National Institutes of Health (NIH) and is the Federal government's lead agency for vision research that leads to sight-saving treatments and plays a key role in reducing visual impairment and blindness. For more information, visit the NEI Website at_ http://www.nei.nih.gov/_.
The National Institutes of Health (NIH) - The Nation's Medical Research Agency - includes 27 Institutes and Centers and is a component of the U. S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical, and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit/_ http://www.nih.gov/.
The Emory Center includes the Department of Ophthalmology, part of the Emory School of Medicine, its clinical sector and all aspects of research. Ranked in the top 20 of/ the U.S. News & World Report's/ annual survey of the nation's best eye centers, Emory Eye Center remains in the top ten of the peer-evaluated/ Ophthalmology Times/ survey. The South's first corneal transplant was performed in Georgia in 1947; its refractive surgery trials were conducted in the 1980s, and it remains at the forefront of many national clinical trials, including those on macular degeneration and glaucoma.