Dynamic Visual Acuity Using Video-Oculography

To evaluate objectively the dynamic visual acuity (DVA), we propose a test based on the chart of Snellen in movement, monitoring the eye movement and pupillary response from an subject. In order to measure the DVA, conditions of luminance and contrast are settled down. Then viewers were asked to look carefully a mobile letter of Snellen controlled by a sinusoidal frequency generator starting from 0.1 Hz (1°/s) and gradually keep increasing, until the viewer is not able to distinguish the character of Snellen. The objective measure of DVA was obtained applying the technique of video-oculography (VOG) in which is possible to detect and analyze the pupillary responses and eye movement by means of image processing. The averages of the changes of pupil diameter of five viewers were found for nasal trajectory since 3.58 mm (0 Hz) to 3.85 mm (1Hz, 10°/s), and for temporal trajectory since 3.54 mm (0 Hz) to 3.96 mm (1 Hz, 10°/s).