A histologic study of regional choroidal dystrophy.

Light and electron microscopy studies of eyes removed from an 84-year-old man after death indicated a normal optic nerve despite severe peripapillary choroidal atrophy. In the area of atrophy, the choriocapillaris, retinal pigment epithelium, and photoreceptors were absent and there was a marked decrease in choroidal arteries and veins. Bruch's membrane was intact except for several breaks in the peripapillary region. Müller cells, in the region of atrophy, produced an aberrant, thick basement membrane either in the outer layers of the neurosensory retina or directly applied to Bruch's membrane. On the basis of this study, we postulate that the primary abnormality in this disease is of the choroidal vasculature.