The effect of light upon the eyes of man and animals encompass such factors as wavelength, intensity, photoperiodicity and duration of exposure. Variations from "norm" of any one factor could be detrimental to ocular health, and variation from "norm" of more than one factor can further enhance development of ocular disease. Albino rats appear more susceptible to phototoxic retinal degeneration than other laboratory animals. This disease occurs under lighting conditions that are considered normal for man. Thus, this species may serve as a test model concerning adverse effects of laboratory animal facility lighting upon its inhabitants. In order to assess the effects of lighting conditions, careful monitoring and evaluation of the lighting characteristics of animal rooms are needed. When this data becomes available, regulatory agencies will be able to recommend lighting conditions in which technical tasks may adequately be performed under illumination that is not detrimental to the laboratory animal.