UV-RADIATION OCULAR EXPOSURE DOSIMETRY

Cataractogenesis by ultraviolet radiation (UVR) has been shown convinc ingly by a host of different laboratory studies. However, crucial epid emiological evidence linking chronic UVR exposure to age-related catar act appears to be lacking, since different environmental studies have led to apparently conflicting results. This paper explores a possible explanation for these conflicting results: errors in dosimetry. Any ep idemiological study depends upon good dosimetry of the subjects' expos ures. A careful examination of the biophysical, physiological and beha vioral factors which determine the level of UVR exposure of the lens r eveals a number of surprises which should explain the apparently confl icting epidemiological results. It is shown that geometrical and behav ioral factors related to sunlight are so important, that by overlookin g these factors, past epidemiological studies of UVR and cataract coul d readily be expected to produce conflicting results.