Pigment clumping and early atrophic changes may be noted. Visual acuity may deteriorate moderately. As the yellow material disappears over time, an area of RPE atrophy remains. This appearance is difficult to distinguish from other causes of macular degeneration. Visual acuity can deteriorate more markedly at this stage.
Hyperopia is common.
Best disease is autosomal dominant with variable penetrance. The abnormality is in the RPE, as noted on histopathology and electrophysiology testing. Fluorescein angiogram reveals blockage of choroidal fluorescence by the vitelliform lesion. The angiogram is otherwise normal at this stage. In the atrophic stage, a transmission defect is noted.