The broad aim of the project is to study the biochemical composition of retina, pigment epithelium and rod outer segments in normal circumstances and in retinal and choroidal diseases of experimental or genetic origin. Topics of current interest are: a) concentration and distribution of inorganic constituents; b) possible involvement of calcium, zinc and copper in retinal and choroidal diseases; c) ultrastructural localization and physiological function of calcium in retina, pigment epithelium, and choroid; d) study of hybrids of RCS and spontaneously hypertensive rats to determine whether the slow onset type of retinal degeneration seen in the latter is inherited at the rdy or another gene locus or is due to light damage in an albino animal. BIBLIOGRAPHIC REFERENCES: Whikehart, D.R. and Hess, H.H.: Properties of liposomes with a phospholipid ratio similar to that of retinal rod outer segment membranes. Interaction with opsin and other proteins. Exp. Eye Res. 24: 279-289, 1977. Fishman, M.L., Oberc, M.A., $ Hess, H.H., and Engel, W.K.: Ultrastructural demonstration of calcium in retina, retinal pigment epithelium, and choroid. Exp. Eye Res. 24: 341-353, 1977.