The dark choroid in posterior retinal dystrophies.

Fourteen families with genetically determined posterior retinal dystrophies were studied by fluorescein angiography. With one exception, the families could be segregated into two clearly defined categories, one in which every member had a dark choroid, and one where each had a light choroid. This implies that the fluorescein angiography provides a means of subdividing certain of these disorders into more specific disease groups.