A: The long term safety of high dose vitamin intake beyond 10 years is unknown. The Age-Related Eye Disease Study [A.R.E.D.S.] specifically looked at elderly patients with vision loss in one eye to see if it could be prevented in the other eye. In A.R.E.D.S., 6340 patients were followed for an average of 6.3 years. Beta-carotene [dietary form of Vitamin A] 15mg, vitamin C 500mg, vitamin E 400mg & zinc oxide 80mg with cupric oxide 2mg were found to decrease the risk of severe loss by 25% vs. placebo. Other supplements such as lutein & xeaxanthin were not included in A.R.E.D.S. Their role is unclear.