Figure 3. Comparison electroretinographic recordings from the affected individual and a normal subject

The full-field rod electroretinogram (ERG) after 30 min of dark adaptation was undetectable. The photopic ERG response and the 30-Hz flicker ERGs were normal. The bright-flash, mixed cone-rod ERG was a negative-type ERG with the amplitude of the b-wave smaller than that of the a-wave. The control (normal) subject was a 28-year-old Japanese woman recruited for the study. With appropriate correction she had full visual acuity, with no history of eye diseases and no serious general diseases.