Objective evaluation of binocular function with pattern reversal VER. IV. Effect of spatial and temporal frequency.

The effects of changing spatial and temporal frequencies on the amplitude of pattern reversal monocular and binocular visual evoked response (VER) were investigated. The pattern reversal VER and the degree of binocular summation (binocular VER amplitude/monocular VER amplitude) were lowest at the spatial frequency (check size) of 0.3 cycles per degree (CPD) and highest at the spatial frequency of 4.0 CPD. The largest VER amplitudes were observed at 1.2 CPD under both the binocular and monocular recording conditions. Regarding the effects of changing temporal frequency (alteration or reversal rate) on the pattern reversal VER, the transient condition (1.5 to 3.0 Hz) did not produce significant binocular summation. At the higher temporal frequencies (6 to 12 Hz), significant binocular summation was produced compared with the transient stimulus condition. At very high temporal frequencies, the degree of the binocular summation showed a decrease. From these results, we selected a pattern with an element around 1.2 CPD with a relatively swift temporal frequency for evaluating binocular function with the pattern reversal VER.