Assessment of ocular exposure to visible light for population studies

We have developed an empirical model with which to estimate the ocular exposure in the visible wavelength band. It incorporates aspects of personal behavior, geographic location, and season, which have been developed from population-based data. As presented herein, the model is strictly valid only for the northern hemisphere, although we discuss how it may be generalized. In conjunction with job history interviews, this model allows the estimate of cumulative exposures from age 30 in our population-based study. We present data on average annual exposure by age, gender, race, education, and reported photophobia. There is a statistically significant difference between males and females, with females having lower exposures. We also found statistically different exposures among the races with African-Americans having slightly higher median exposures than whites. Exposures decrease with level of education and with reported photophobia. These data provide the basis for characterizing lifetime exposure for the general population and should permit exploration of the relationship between eye disease and cumulative ocular exposure to visible light.