Figure 4. Electroretinograms of the patient at baseline A: and after 30 months B: compared to a normal control C: showing severely reduced scotopic and photopic responses, with evidence of progression over the follow-up period, in keeping with the diffuse rod-cone photoreceptor degeneration. The four columns represent different categories of electroretinogram (ERG) response, labeled according to the names suggested by the ISCEV standard [7]. Each graph shows two repetitions of the same response, all recorded from the left eye.