A trial of objective visual field measurement by pupillary reaction
We created pupil perimetry that could objectively analyze the visual fields utilizing the light reflex with the Visual Evoked Response Imaging System (VERIS). Nineteen hexagonal stimulating elements were used to stimulate up to 15 degrees of eccentricity at 2 Hz. The evoked light reflex was recorded by the infrared camera, and the changes in the maximum transverse diameter of the pupil were measured using a pupillometer. Then, the amplitude of the light reflex evoked by local retinal stimulation was calculated using VERIS Science 4.1. The variation coefficient of the light reflex was the smallest in healthy individuals and its amplitude was greatest when white-black stimuli were delivered with an indoor luminance of 5 asb. Therefore, this was established as the optimal testing condition for the present perimetric system. In patients with visual field defects, the amplitude of the light reflex at areas of visual field loss was significantly smaller than that at normal areas, but minute defects could not be detected. Pupil perimetry utilizing VERIS could objectively analyze the visual fields, but the size of the stimulated field must be expanded and the resolution must be improved before it can be used clinically. (Accepted on November 18, 2008)
