ANTIOXIDANTS AND EYE DISEASE

Oxidative mechanisms are believed to play an important role in the pat hogenesis of age-related eye disease, in particular, cataract and macu lar degeneration, the two most important causes of visual impairment i n older adults. For this reason, there is considerable interest in det ermining whether vitamins and trace minerals with antioxidant properti es can be of benefit in preventing the onset or progression of disabli ng eye disease. Basic research studies have shown that antioxidants ca n protect against the cumulative effects of oxidative stress in animal models of cataract and macular degeneration. Data from observational epidemiologic studies in humans, however, are inconclusive. While resu lts from several studies, primarily cross-sectional and case-control, are compatible with a possible protective role for micronutrients in c ataract and macular degeneration, data for specific nutrients or speci fic disease types have often been inconsistent. Further, these observa tional studies are Limited because of the inherent imprecision of diet ary exposure data and the likely effects of uncontrolled confounding. Thus, reliable data regarding a potentially important benefit of vitam in supplementation in eye disease will emerge mainly from well-designe d, large-scale, randomized trials. Such data are already being collect ed in the National Eye Institute-sponsored Age Related Eye Disease Stu dy, as well as in the Physicians' Health Study and Women's Health Stud y.