Measurements of Ocular Saccadic Velocities; Computerized Digital Video Measurement Technique

Han, Sueng Han

Abstract

We have measured the saccadic velocties of nystagmoid and normal ocular movements. The ocular motions of normal subjects and of patients with nystagmus were videotaped using a 3 CCD(color) high resolution camera at 30 frames per second. 8.5-second video segments were selected for analysis. The data was processed digitally using a commercially available image analysis program in a standard 32-bit microcomputer. Measurements were replicated by two analysts. Saccadic velocities of each type of ocular movement were calculated and displayed. Measurement errors between observers and with repeated trials were less than 3%. This new technique is non-invasive, efficient and requires only a camera to obtain video data. It has less noise than conventional methods because of the utilization of video lenses providing very good spatial resolution(1 pixel, 0.33mm), so motion range is much larger than pixel size.