Early effects of sodium iodate on the slow off-effects, particularly the h-wave, and on the c-wave of the DC recorded electroretinogram in rabbit.

The early effects of intravenously administered sodium iodate (NaIO3) on the slow, negative 'off-effect', the h-wave, and on the slow, positive 'on-effect', the c-wave, of the DC recorded electroretinogram were studied in 8 rabbits. Both the h- and c-waves disappeared gradually after NaIO3 administration and were replaced by potentials of opposite polarity. These results strongly support the assumption that the h-wave originates in the pigment epithelium and represents the reversal of events underlying the c-wave. The slow, positive 'off-effect', the g-wave, elicited by 'dark flashes' was seen to pass into the potential replacing the h-wave after NaIO3 treatment.