Figure 2.

Full-field ERG responses from a normal subject and from four patients with retinitis pigmentosa. Stimulus onset is vertical hatched lines for columns 1 and 2 and vertical shock artifacts for column 3. Rod b-wave implicit times in column 1 and cone implicit times in column 3 are designated with arrows. Calibration symbol (lower right corner) signifies 50 msec horizontally and 100 μV vertically for all tracings. Under these test conditions, normal amplitudes are ≥ 100 μV (left column), ≥350 μV (middle column), and ≥50 μV (right column). Normal rod implicit time is ≤108 msec and normal cone implicit time is ≤32 msec. (From Berson, 1976.)