RETINAL LIGHT DAMAGE - PROTECTIVE EFFECT OF ALPHA-TOCOPHEROL

We studied histologically the protective effect of alpha-tocopherol to retinal light damage. After 3-week-old albino rats were fed with an a lpha-tocopherol deficient or supplemented diet and kept in a 12-hour d im light/12-hour dark environment for 8 weeks, each animal was exposed to intense light (2500 lux) for 1, 3, 6, 12, 24, and 72 hours. The ey es were enucleated and prepared for transmission electron microscopy s tudy and image analysis of phagosomes. Before light exposure, the alph a-tocopherol content of the neural retina of the deficient and supplem ented groups was 0.3 mu g and 23.34 mu g, respectively. After 1- and 3 -hour exposures, morphological changes in the retinal pigment epitheli um and photoreceptor membranes were more extensive in the deficient gr oup than in the supplemented group. After a 24-hour exposure, pyknotic photoreceptor nuclei were more numerous in the deficient group than t he supplemented group. After 3-, 6-, and 12-hour exposures, large phag osomes were more numerous in the deficient group than in the supplemen ted group. These findings suggest that alpha-tocopherol can protect th e retina from light injury for up to 24 hours of exposure. (C) 1997 Ja panese Ophthalmological Society.