If every American at risk for advanced age-related macular degeneration (AMD) took daily supplements of antioxidant vitamins and zinc, more than 300,000 people could avoid AMD-associated vision loss over the next five years, according to results of a new government study led in part by researchers at Johns Hopkins' Wilmer Eye Institute.
Reporting on the public health implications of the national Age-Related Eye Disease Study (AREDS), published two years ago and supported by the National Eye Institute, a team of Johns Hopkins ophthalmologists and other scientists participating in AREDS estimate there are 8 million people in the United States age 55 or older at high risk for advanced forms of the disorder that destroys central vision and who could benefit from daily vitamin treatment. They include people with an intermediate stage of AMD in one or both eyes, or advanced AMD in one eye. AMD is the leading cause of blindness in developed countries.
The original AREDS investigation, of 4,757 adults ages 55 to 80 with varying levels of AMD, showed that among people at high risk for late-stage AMD and central vision blindness in both eyes, a dietary supplement of vitamins C, E and beta carotene along with zinc lowered the risk of progressing to advanced disease by about 25 percent. Daily supplements also reduced the risk of vision loss by about 19 percent. By contrast, the supplements had no preventive effects against development of cataracts or for people without AMD or an early stage of AMD.
"Without treatment to reduce their risk, we estimate that 1.3 million adults would develop the advanced stage of AMD," says Neil M. Bressler, M.D., lead author of the current study, published in the November issue of the Archives of Ophthalmology, and the James P. Gills Professor of Ophthalmology at Hopkins. "The challenge lies is identifying individuals at risk, since many with the intermediate stage of AMD do not have symptoms. Regular retina exams performed by an ophthalmologist could identify those in this intermediate stage."
Bressler and colleagues estimate that, without treatment, the prevalence of advanced AMD within five years among those with intermediate AMD in one eye is 6.3 percent. They also estimate 26.4 percent of those with intermediate AMD in both eyes and 43 percent of those with advanced AMD in one eye would develop advanced AMD in five years without treatment.
The supplements recommended contain 500 milligrams of vitamin C, 400 milligrams of vitamin E, 15 milligrams of beta carotene, 80 milligrams of zinc as zinc oxide and 2 milligrams of copper as cupric oxide.
Coauthors of the current report with the AREDS Research Group, supported by the National Institutes of Health and Bausch & Lomb Inc., were Susan B. Bressler, M.D.; Nathan G. Congdon, M.D.; Frederick L. Ferris III, M.D.; David S. Friedman, M.D.; Ronald Klein, M.D.; Anne S. Lindblad, Ph.D.; Roy C. Milton, Ph.D.; and Johanna M. Seddon, M.D.
AREDS Research Group, "Potential Public Health Impact of Age-Related Eye Disease Study Results," Archives of Ophthalmology, Nov. 2003, Vol. 121, pages 1621-1624.
Wilmer Eye Institute at Johns Hopkins
National Eye Institute – AREDS study
Archives of Ophthalmology
Source: Johns Hopkins