Ocular effects of UV-B exposure.

Although an association between UV-B exposure and ocular damage has been long suspected, this relationship is still not well quantified. Cataract is the most significant ocular damage associated with UV-B exposure. Initial studies of the association between UV-B exposure and cataract were hampered by a lack of precision in the assessment of cataract and a failure to separate cataract types. With a few exceptions, most studies have not assessed individual ocular UV-B exposure but have used ambient levels or isolated behaviours. Ecologic studies show there is more cataract in sunny areas, but whereas ambient UV-B fluxes may change by a factor of 3 or 4 over the globe, individual behaviour can change ocular exposure in a given location by 20-fold or more. The Chesapeake Bay Watermen studies assessed individual ocular UV-B exposure and have shown a consistent relationship between exposure to UV-B and the risk of both cortical and posterior subcapsular cataract. However, further work to refine these findings is sorely needed.