RESUMEN
A revolving drum, about 40cm in diameter, with vertical stripes on its surface, was used in examination. The drum was held 50cm in front of the eyes of aircrew receiving examination. The horizontal optokinetic nystagmus was elicited by vertical black stripes moving horizontally. The examinee was instructed to gaze straight ahead at the black stripes, without deliberate fixation. The drum speed was kept constant at 20?, 40?,60?,80?,100?,120?/s. The velocity of the slow component of nystagmus, its frequency, amplitude and symmetry were recorded when the reaction reached its peak.The slow component velocity and the frequency were increased with the drum speed, but the amplitude was decreased with the drum speed. The wave forms of optokinetic nystagmus were usually of five types.