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Abstract
Formalin-fixed eyes of a patient with autosomally dominant retinitis pigmentosa were studied by light and electron microscopy. The only photoreceptors present were foveal cones. The outer segments of these cones were shorter and wider than normal and their discs were disoriented even at their base. Foveal pigment epithelium cells contained excessive amounts of lipofuscin in large spherical clusters, reduced amounts of melanin, and were in different stages of migration away from Bruch's membrane. The existence of such quantities of lipofuscin in foveal pigment epithelium implies that these cells are capable of phagocytizing outer segment material in this form of retinitis pigmentosa. In nonfoveal retina patches of a different type of pigment epithelium occurred which contained no lipofuscin, but instead, large amounts of melanin. These latter cells appear to be solely responsible for the bone corpuscle pigmentation in this disease.