More than 1,500 patients with retinitis pigmentosa and allied diseases are on file; a Specialized Clinical Research Center has been established to study the natural histories of these diseases and to do clinico-pathologic correlations. Diseases under investigation include different genetic types of retinitis pigmentosa, hereditary macular degenerations and gyrate atrophy of the choroid and retina. An eye donor program has been established and postmortem tissue from affected patients is being studied with a multidisciplined approach. Information on histories and on findings on ocular examinations of patients has been stored in a computerized data bank for biostatistical analysis to improve classification of these diseases and to study factors that may affect the natural histories. Projects proposed as part of this renewal application include prospective studies on the natural history of these ocular diseases including focal measures of retinal function from known retinal areas visualized with a stimulator ophthalmoscope, electron microscopic studies to define ultrastructural abnormalities in different regions of donor eyes, biochemical studies of photoreceptors to see if phospholipid or phosphoprotein synthesis is altered, biochemical studies of cultured pigment epithelium to see if glycosaminoglycan synthesis is abnormal, and studies on enzyme activities in cultured skin fibroblasts of patients with hereditary retinal disease with known systemic abnormalities. Biostatistical analysis will continue on information stored in the data bank and will also be done on information added to the data bank from prospective studies on natural history. Observations on postmortem donor eyes will be correlated with psychophysical and electrophysiological findings in donors prior to death and also compared with findings in living affected relatives of donors and with findings in patients in the data bank with the same types of retinitis pigmentosa and allied diseases.