Assessment of epidemiological evidence that exposure to solar ultraviolet radiation causes cataract.

In this paper an assessment is made of the evidence that exposure to solar ultraviolet radiation is causally associated with cataract. The evidence is reviewed separately for cortical, nuclear and posterior subcapsular cataract. The assessment examines the consistency and magnitude of an association, the dose-response relationship, supporting ecological data, and data from animal studies. Based on the assessment, it is concluded that there is sufficient experimental evidence that exposure to artificial sources of UV-B can cause cortical opacities in laboratory animals. However, there is only limited evidence that exposure to solar UV-B causes cortical opacities in humans. Similarly, there is only limited evidence that exposure to solar UV-B causes posterior subcapsular cataract in humans. The epidemiological evidence is consistent in suggesting that nuclear cataracts are not causally associated with exposure to solar UV-B.