A continuing problem in night driving is the effect of glare sources, as oncoming headlights, on the visual sensitivity of the driver. This study was undertaken to determine the effect on dark adapted foveal acuity of brief, bright sources of light. All measures were made with a hecht-shlaer adaptometer. A series of dark adaptation curves are presented. Regular families of curves were found for each subject' the initial threshold and the total time to readapt varied systematically with the intensity and duration of the adaptation source. Two other questions that were investigated were the size of the adapting field, and the length of exposure time beyond which no further effects were found. Various products of intensity and time of the glare sources have been compared.
Abstract