EFFECT OF INDUCED FIXATION DISPARITY BY NEGATIVE LENSES ON THE VISUALLY EVOKED-POTENTIAL WAVE

The effect of induced fixation disparity produced by negative lenses a nd base-in prisms on the pattern visually evoked potential (VEP) was i nvestigated. Monocular and binocular pattern reversal VEP were recorde d through the negative lenses and base-in prisms using a 9.5 min arc c heck size. The results suggest that the mean binocular amplitude was 2 7% larger than the mean monocular amplitude which indicates partial su mmation in the absence of negative lenses or base-in prisms. A reducti on of the binocular VEP amplitude appears to arise in the presence of fixation disparity induced by both the negative lenses and base-in pri sms. Both the prisms and the negative lenses had no appreciable effect on the monocular VEP amplitude.