Hemiretinal stimuli elicit different amplitudes in the pattern electroretinogram.

Pattern electroretinograms were elicited in 13 normal eyes by half-field checkerboard stimulation of nasal-temporal and upper-lower retinal areas. With nasal-temporal visual half-field stimulation the p-q component amplitude of the nasal hemiretina was significantly larger than that of the temporal hemiretina. With upper-lower visual half-field stimulation the amplitude was significantly larger for the upper than for the lower hemiretina. No significant differences were found with respect to the component latency. Finding the p-q amplitude of the pattern electroretinogram to be closely related to the distribution of nerve cells in the innermost retinal layer supports the conclusion that the pattern response is generated in the more proximal retinal layers including the retinal ganglion cells.