Abstract

The PI, PII, and PIII fundamental "Processes" described by Granit (1933) form the major component waves of the electroretinogram (ERG), particularily under dark-adapted (scotopic) conditions. The leading edge of scotopic PIII (i.e. "fast PIII") shapes the negative a-wave which originates directly from light evoked hyperpolarization of rod photoreceptors (Penn and Hagins, 1969). Scotopic PII is seen primarily as the phasic positive b-wave which results from local depolarization of Muller glial cells by a light-evoked K⁺ efflux from bipolar cells in distal retina (Faber, 1969; Miller and Dowling, 1970)

© 1993 Optical Society of America