The electrical activity of the retina is influenced by a previous illumination with a flash of light. Dodt1 (1952) found that the amplitude of the b-wave of the human electroretinogram (ERG) is increased from bare perceptibility to the normal value when the dark interval between the previous and test flashes is changed from 0.1 to 1.5 seconds. A similar depression of the b-wave following a previous illumination was confirmed by many investigators.2-5 Mahneke3 (1957) has also noted that this depression phase is followed by a supernormal phase which is evidenced by increased amplitude of the b-wave Thus, the recovery cycle of the human ERG after a previous conditioning flash is characterized by an initial depression and a late facilitation of the b-wave. However, little attention has so far been paid to this late facilitation of the b-wave in the recovery cycle.
NAGAYA T, OISHI S, KUNO M. The Central Influence upon the Electroretinogram Evoked by Double Flashes. Arch Ophthalmol. 1962;68(4):532-537. doi:10.1001/archopht.1962.00960030536020