Figure 3. Electrophysiology. Full-field ERGs and pattern ERGs from the right (row 1) and left eye (row 2) of the patient and normal examples (row 3) for comparison. Full-field ERGs were performed using corneal electrodes in August 2007; pattern ERGs had been recorded to a 30 degree field checkerboard stimulus using periorbital surface electrodes two years earlier. Dark-adapted ERGs are shown for flash intensities of 0.01 and 11.5 cd.s.m⁻²; light-adapted ERGs for a flash intensity of 3.0 cd.s.m⁻² at 30 Hz (flicker) and at 2 Hz.. ON-OFF ERGs used an orange stimulus (560 cd.m⁻², duration 200 ms) superimposed on a green background (150 cd.m⁻²). S-cone ERGs used a blue stimulus (445 nm, 80 cd.m⁻²) on an orange background (620 nm, 560 cd.m⁻²). Eye movement artifacts are replaced by broken lines for clarity. S-cone ERGs were unavailable for the right eye.