Rod-cone interaction in patients with fundus flavimaculatus.

Dark adaptation and the rise of cone flicker threshold (25 Hz) during dark adaptation were measured psychophysically in three patients with fundus flavimaculatus. The dark adaptation curve showed a delayed rod-cone break but a normal final rod threshold in all these patients. However, the rise of cone flicker threshold during dark adaptation was not delayed and also reached a normal final value. This indicates that the delay in rod dark adaptation does not influence the rise of cone flicker threshold during dark adaptation. This finding contrasts with current concepts that the rise of the cone flicker threshold reflects an increasing inhibitory influence of dark adapting rods.