The corneoretinal potential(CRP) exists in a relatively electrically stable state but is affected by ocular diseases and light. Other causes which change the CRP are not well-known. Recently, authors have observed that the CRP changes before and after optokinetic stimulation at a constant velocity, so corneoretinal potential changes in normal subjects were investigated before and after optokinetic stimulations at four constant velocities. Two conditions of optokinetic stimulus were employed in this experiment. First, the subjects fixed their eyes on a stationary target in front of black stripes during the optokinetic stimulation. This mainly induced retinal stimulation(Condition A). Next, the subjects with their eyes followed moving black stripes during optokinetic stimulation(Condition B), which mainly caused foveal stimulation. Stimulus speeds of 30°/sec, 45°/sec, 60°/sec, and 90°/sec constant velocities were used. The CRP was calculated as milimeters of pen deflection of velocity tracing before and after optokinetic stimulation. The ratio of CRP changes after optokinetic stimulation was compared to the pre-optokinetic stimulation. The results obtained were as follows : 1) After optokinetic stimulation at 30°/sec constant velocity : The mean ratio of CRP changes was 1.22±0.14 in Condition A(retinal vision state) and 1.01±0.01 in Condition B(foveal vision state). The difference of CRP changes between the two conditions was statistically significant(t-test, p<0.01). 2) After optokinetic stimulation at 45°/sec, 60°/sec and 90°/sec constant velocity : The mean ratio of CRP changes in A and B Conditions was 1.07±0.05, 1.11±0.05 at 45°/sec, 1.09±0.04, 1.16±0.06 at 60°/sec, and 1.10±0.11, 1.17±0.05 at 90°/sec. In all conditions after optokinetic stimulations at 45°/sec, 60°/sec, and 90°/sec, the increase of corneoretinal potential was significant(t-test, p<0.01). The CRP after optokinetic stimulation increased in Condition A at four stimulus speeds. In Condition B, however, the CRP did not increase after constant velocity stimulation of 30°/sec, but increased after constant velocity stimulations of 45°/sec, 60°/sec, and 90°/sec. These data support the premise that the increase of corneoretinal potentials after moderate and high speed optokinetic stimulation is at transient physiological phenomenon due to the rise of peripheral retinal cell activity mainly, whereas corneoretinal potential after low speed optokinetic stimulation does not increase mainly due to foveal vision.