Vitamin supplements could halt thousands of cases of blindness
than 300,000 people at risk for advanced age-related macular
degeneration avoid vision loss over the next five years, according
to results of a new US government study.
Daily supplements of antioxidant vitamins and zinc could help more than 300,000 people at risk for advanced age-related macular degeneration avoid vision loss over the next five years, according to results of a new government study.
The findings, published in this month's Archives of Ophthalmology, are based on the Age-Related Eye Disease Study (AREDS), published two years ago and supported by the US 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 per cent. Daily supplements also reduced the risk of vision loss by about 19 per cent.
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," said Neil M. Bressler, lead author of the current study. "The challenge lies in 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 per cent. They also estimate 26.4 per cent of those with intermediate AMD in both eyes and 43 per cent 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.
