The role of sunlight in human cataract formation.

This review summarizes and integrates new findings concerning the role of near-ultraviolet radiation, as is present in sunlight and common artificial light sources, in stimulating human and animal cataract formation. Epidemiological and basic research studies are summarized and critical statements concerning them are offered. Although certain questions still remain unanswered, the evidence that near-UV radiation does stimulate cataract formation is very strong. Avoidance of excessive exposure to near-ultraviolet light and the use of protective lenses that filter it out are suggested to prevent the enhancement of human cataract formation by near-UV light.