Nov. 1, 2006
NOTE TO EDITORS: This news release is based on an embargoed news release provided by the National Eye Institute of the National Institutes of Health.
Laser Treatment Is Ineffective For Early Age-Related Macular Degeneration
An extensive National Institutes of Health (NIH) study that included the University of Iowa has found that low-intensity laser treatment does not prevent complications or vision loss due to early age-related macular degeneration (AMD).
The treatment had been thought to possibly help slow or prevent vision loss from AMD, which is the leading cause of blindness in the United States for people age 60 and older.
This major finding of the Complications of Age-Related Macular Degeneration Prevention Trial (CAPT) will appear in the November 2006 issue of the journal Ophthalmology. The study involved 1,052 participants nationwide, including 56 who participated through the UI Department of Ophthalmology and Visual Sciences. The research was funded by the National Eye Institute (NEI) of the NIH.
The study was designed to assess the safety and effectiveness of laser treatment in preventing vision loss among people who had large drusen -- yellowish deposits under the retina -- in both eyes, said James Folk, M.D., principal investigator of the study at the UI site and professor of ophthalmology and visual sciences at the UI Roy J. and Lucille A. Carver College of Medicine and an ophthalmologist at UI Hospitals and Clinics.
"Eyes with large drusen are at increased risk of progressing to advanced AMD, with accompanying vision loss. However, the CAPT study showed using laser treatment to reduce drusen does not improve outcomes. We found no difference in vision or how AMD advanced between treated and untreated eyes," Folk said. "This means doctors using this technique should reconsider its use in patients with AMD.
"Oftentimes we think study results are useful only if they tell us what does work to treat a disease. However, it is equally important to know what approaches are not effective, to help patients and clinics alike not waste their effort, time or money," Folk added. "Further analysis of the information gather by the CAPT study will also yield clues into the causes of advanced AMD."
First used in the 1970s, low-intensity laser treatment had been shown to reduce the extent of drusen. However, previous studies evaluating the impact of laser treatment on vision had been small and inconsistent in their findings.
"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 Paul A. Sieving, M.D., Ph.D., director of the NEI.
Study participants were age 50 or older (average age of 71), had 10 or more large drusen and a visual acuity of 20/40 or better in each eye. One eye of each participant was treated. Each volunteer's treated eye, along with the untreated eye, was observed for changes throughout the five-year 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.
"At present, the only established way to decrease risk of vision loss in people with large drusen is to take daily supplements of vitamins and minerals, as used in a different study, the NEI-supported Age-Related Eye Disease Study," Sieving said.
That 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," Folk said.
Additional information on different forms of AMD and specific steps to preserve vision can be found in "Protect Your Sight: How to Save Your Vision in the Epidemic of Age-Related Macular Degeneration," a book written by Folk and Mark E. Wilkinson, O.D., UI clinical associate professor of ophthalmology.
The book also contains information on visual aids, research and tips on how to keep up with the latest discoveries and treatments. The book can be read online for free at http://www.medrounds.org/protect-your-sight. Print copies also can be ordered for a fee at the site.
"It's very difficult for patients, and even doctors, to keep up with advances that save vision and know what does or doesn't work," Folk said. "We want to help them make informed decisions about their eye care."
It is best to consult with a physician before making any changes to your health care routine.
STORY SOURCE: University of Iowa Health Science Relations, 5137 Westlawn, Iowa City, Iowa 5224-1178
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