Effect of Physical and Mental Burden on Elapsed Time of Visual Perception in the Initial Stage of Dark Adaptation : measurement with a new device

Abstract

It is known that visual perception in the dark is different according to conditions of environment and to the individual visual acuity, and also known that it is influenced by certain disease, fatigue and alcohol ingestion even within the same individual. It may, therefore, be possible to determine the event of lowering of the physical and mental functions by means of measuring the elapsed time of visual perception in the initial stage of dark adaptation. For this purpose an instrument equipped with an electronic timer was developed, by which the restoration time of the visual perception under a low illumination (5 lux) preceded by a 5 seconds' exposure in a high illumination (3000 lux) could be measured precisely. In the present study an outline of the instrument and a few data on basic experiments were described. It was suggested that the obtained values by this method were closely related to the extent of lowering of physical and mental functions.