New York – In people older than 55 years who have findings on dilated eye exams that indicate intermediate age-related macular degeneration, a supplement of antioxidants plus zinc may delay progression of the disease, according to an Archives Express article in the October issue of the Archives of Ophthalmology.

Researchers with the Age-Related Eye Disease Study (AREDS, Report No. 8) studied 3640 individuals aged 55 to 80 years for an average of 6.3 years who were evaluated for signs of age-related degeneration of the macula (AMD), the leading cause of visual impairment and loss in people over age 65.

The researchers evaluated the effect of high-dose vitamins C and E, beta carotene, and zinc supplements on AMD progression and visual acuity. The observational and experimental data suggest that antioxidant and/or zinc supplements may delay progression of AMD and vision loss. Participants with signs of early AMD who took antioxidants plus zinc significantly reduced their risk of developing advanced AMD.

The participants were divided into 4 categories based on preexisting eye lesions and degeneration present before the study, roughly corresponding to their risk of AMD progression. They were evaluated every 6 months for retinal changes indicating AMD progression. The participants were randomly assigned to receive 1 of 4 daily supplements:

antioxidants (vitamin C, 500 mg; vitamin E, 400 IU; and beta carotene, 15 mg)
zinc, 80 mg, as zinc oxide; and copper, 2 mg, as cupric oxide
antioxidants plus zinc
placebo
"Comparisons with placebo demonstrated a statistically significant odds reduction for the development of advanced AMD with antioxidants plus zinc [28% reduced risk]," the researchers write.

"The [reduced risks] for zinc alone and antioxidants alone are [25%] and [20%] respectively," they add. "The only statistically significant reduction in rates of at least moderate visual acuity loss occurred in higher-risk persons assigned to receive antioxidants plus zinc [27% reduced risk]."

The authors note that the doses of vitamins C and E and the dose of zinc used in the study are higher than the recommended daily amount and therefore can only be obtained by taking supplements. They recommend that, because of adverse effects documented in other studies, smokers should not take beta carotene.

"Based on data from AREDS, persons older than 55 years should have dilated eye examinations to determine their risk of developing advanced AMD," the authors conclude. "Those with extensive intermediate size drusen, at least one large druse, or noncentral [atrophy] in one or both eyes or those with advanced AMD or vision loss due to AMD in one eye, and without contraindications such as smoking, should consider taking a supplement of antioxidants plus zinc such as that used in this study."

In a related article, with AREDS (Report No. 9) found that a high-dose formulation of vitamin C, vitamin E and beta carotene had no apparent effect on reducing the risk of development of age-related cataract.

In an accompanying editorial, Lee M. Jampol, MD, of the Department of Ophthalmology at Northwestern University, Chicago, notes that in the growing trend to prevent or ameliorate medical conditions and the aging process, many patients "attack" by taking various supplements. He states that because the cause of AMD is uncertain, it is difficult to determine what supplements might be helpful.

Dr. Jampol states that, "Surprisingly and fortunately, [the AREDS] results demonstrate impressive efficacy of the interventions for intermediate and advanced AMD. This contrasts with the disappointing results to date of similar supplementation for the prevention of cancer, stroke and cardiovascular disease."

Dr. Jampol notes that, "… the study tells us nothing about the value of supplementation in [Categories 1 and 2]. Supplementation was not demonstrated to prevent progression from Category 2 to category 3 or 4.

"Only the combination of zinc and antioxidants statistically reduced the odds of patients developing advanced AMD," Dr. Jampol states. "The only statistically significant reduction of moderate visual loss occurred in patients assigned to antioxidants plus zinc.

"… the results do demonstrate a consistent and cohesive picture of the modest efficacy of the zinc alone, the antioxidants alone, and more of an effect from the combination of the 2," Dr. Jampol observes. "We do not, of course, know whether 1, 2, or all 3 of the antioxidants are responsible for the beneficial effect.

"I would conclude that those patients of any age who demonstrate extensive intermediate sized drusen, large drusen, or especially those who have advanced AMD in one eye, should consider taking a supplement containing these dosages of anti-oxidants and zinc, Dr. Jampol summarizes. "It seems desirable that this supplement should be taken indefinitely, though AREDS cannot determine ideal duration of treatment."

According to background information in the article, AMD is the leading cause of visual impairment and blindness in the United States and elsewhere among people 65 years and older. There is no proven treatment to slow or prevent development of advanced AMD.

Arch Ophthalmol. 2001;119:1417-1436, 1439-1452, 1533-1534