The Age-Related Eye Disease Study (AREDS) is a major clinical trial sponsored by the National Eye Institute, one of the federal government's National Institutes of Health. The AREDS was designed to learn more about the natural history and risk factors of age-related macular degeneration (AMD) and cataract and to evaluate the effect of high doses of vitamin C, vitamin E, beta-carotene and zinc on the progression of AMD and cataract. Results from the AREDS showed that high levels of antioxidants and zinc significantly reduce the risk of advanced AMD and its associated vision loss. These same nutrients had no significant effect on the development or progression of cataract.
Age-Related Eye Disease Study 2 (AREDS2)
In May 2013, the NEI completed the Age-Related Eye Disease Study 2, which tested several changes to the formulation. They tried adding omega-3 fatty acids, as well as the antioxidants lutein and zeaxanthin, which are in the same family of nutrients as beta-carotene. The researchers also tried substituting lutein and zeaxanthin for beta-carotene, which prior studies had associated with an increased risk of lung cancer in smokers. The study found that while omega-3 fatty acids had no effect on the formulation, lutein and zeaxanthin together appeared to be a safe and effective alternative to beta-carotene.