The electroretinogram in dogs with inherited cone degeneration.

The electroretinogram (ERG) of hemeralopic Alaskan malamute dogs contains only rod components. There is absence of the photopic b-wave which is normally elicited with red light stimuli during dark adaptation and, using flicker stimulation, only the first or rod branch of the flicker fusion response curve is present. At high stimulus intensity levels, the flicker response of hemeralopes is absent. A normal ERG is recorded from affected dogs using blue light stimuli and low intensity white light. In the adult hemeralope, the retina contains no cones.