Pattern dystrophy of the retinal pigment epithelium.

The pattern dystrophies are a group of hereditary macular dystrophies characterized by lesions of the retinal pigment epithelium (RPE) arranged in various patterns of dots, lines, and branched figures. This report of two pedigrees expands the clinical spectrum. The onset is usually in the second and third decade, there is great variation in fundus appearance, vision may be severely affected, the EOG is not always abnormal, and the fundus lesions change with time. The lesions resemble those of Best's vitelliform degeneration and fundus flavimaculatus, and, possibly, also represent abnormal lipofuscin accumulation within degenerating retinal pigment epithelial cells.