Bull's-eye maculopathy and negative electroretinogram.

The authors studied four patients with a bull's-eye maculopathy and otherwise normal fundus. A single-flash electroretinogram (ERG) with an intense white light stimulus in the dark showed a normal a-wave but reduced b-wave amplitude (negative ERG). Other findings common to all four patients were initially normal visual acuity, subsequent progressive decrease in visual acuity, mild to moderate deficiency of color vision, normal peripheral visual field, relatively well preserved cone ERG, normal 30-Hz flicker ERG, normal EOG, near emmetropia and selective involvement in males. Cone dystrophy, retinitis pigmentosa, congenital retinoschisis, congenital stationary night blindness, and Batten's disease were excluded. The correlation between this disease and benign concentric annular macular dystrophy is discussed.