Pattern-reversal retinal potentials (PRRPs) are electrical signals generated within the human retina, possibly by the retinal ganglion cells, when a phase-alternating checkerboard pattern (or grating) is viewed. This study systematically examined the effects of varying the spatial and/or temporal frequency of the stimulus pattern on the resulting PRRP. A significant variation in PRRP amplitude, which was dependent on both the spatial and temporal frequency of the stimulus, was observed. Optimum response amplitude was obtained with a low spatial frequency (0.250 cy/deg) at intermediate temporal frequencies (3.75 or 7.50 Hz). A linear regression, fit to the average PRRP amplitude vs. spatial frequency data for either the 1.88 or 3.75 Hz conditions, appears to predict average subjective visual acuity.