Ocular Asymmetry in Electrooculographic Responses

Abstract

Between the cornea and the posterior pole of the eye, there is a transepithelial potential capable of being registered through an electrooculogram (EOG). It is questionable whether electrooculographic responses are similar in both eyes despite ocular dominance in human beings. We studied the effect of different electrooculographic stimulation parameters, in terms of directionality, linear and angular velocity, contrast, and state of adaptation to light/dark, that may induce possible interocular differences in visual function. The study was carried out with electroencephalography-type surface electrodes placed in the medial, lateral, superior, and inferior positions of both human eyes to record the eye movements. We found a greater amplitude of the EOG response in the left eye than to the right eye for light bars moving from right to left (p < 0.01; t-test). The EOG response amplitude was similar in both eyes for light bars moving in vertical directions, but greater than horizontal or rotational stimuli. We conclude that vertical stimuli should be used for EOG functional evaluation of eye movements, since horizontal stimuli generate significant interocular differences.