Figure  1. .

Autofluorescence (A) and color image (B) of right and left retina of affected patient aged 59 years (family 4), showing areas of central atrophy of retinal pigment epithelium (RPE) and choroid. C, Color image of right and left retina of affected patient aged 24 years (family 1), showing subtle RPE depigmentation around fovea and crystals at the macula. D, Full-field ERGs (International Society for Clinical Electrophysiology of Vision [ISCEV]) in an unaffected subject (top row) and in a representative patient from family 9 (bottom row). In the patient, dark-adapted responses to the dimmest flash (0.002 candela [cd]-s/m²) are undetectable. Increasing stimulus intensity (“rod” 0.012 cd-s/m²) produces an abrupt increase in amplitude and a delayed rod ERG. At higher flash energies (“standard” 3.0 cd-s/m² and “maximum” 11.5 cd-s/m²), the a-wave commences normally but develops a broadened trough before a high-amplitude, sharply rising b-wave that approaches the upper limit of normality (supernormal). Flicker and photopic single-flash ERGs were performed after 10 min of light adaptation. ^ISCEV-standard 30-Hz flicker ERGs show delay and marked reduction. The photopic single-flash ERG is delayed and subnormal, with a simplified waveform and delayed recovery after the beta-wave. Broken lines replace blink artifacts, frequently seen after the ERGs with strong flashes.