Ocular structure in vitamin A deficiency in the monkey

Abstract

1. The role of vitamin A in the metabolism of cone cells of the retina was investigated, from the morphological angle, by studying their structure in induced deficiency of vitamin A in three monkeys. 2. Unequivocal signs of structural damage were observed in the cone and rod cells of the deficient animals, which also showed the classical signs of vitamin A deficiency in other organs. 3. In vitamin A deficiency, damage to the visual cell layer of the retina occurred in one monkey in the absence of corneal involvement. This finding suggests that chronic vitamin A deficiency in the community may lead to progressive damage to the visual cells in a much larger number of persons than the incidence figures for keratomalacia indicate. 4. Degeneration of pigment epithelium was present in retinal sections from all the deficient animals. The possible role of the pigment epithelium in the pathogenesis of the visual defect in vitamin A deficiency has been discussed. 5. Degenerative changes were noted in Descemet's endothelium. This damage may contribute to the degeneration of the corneal epithelium.