Daylight, diet, and age-related cataract.

Blindness due to cataract continues to take a heavy toll on economic, social, and personal resources. Research into factors that may cause or prevent cataracts is of the highest priority. In this paper, the epidemiological evidence is summarized on the role of sunlight exposure and antioxidants for cataract. To date, there are consistent findings linking ultraviolet B (UV-B) radiation to cataract, particularly cortical and posterior subcapsular opacities. Antioxidants are likely to exert a protective effect against oxidative stress in the lens, but the current epidemiologic data present less coherent support for this hypothesis. Difficulties in summarizing these data include different methods for assessing antioxidant status, widely varying populations, and different research designs. Nevertheless, most studies have found some measure of antioxidant status to be associated with some type of cataract. Future research directions are described.