Evaluation of visual fatigue during VDT tasks

This study was designed to evaluate visual fatigue induced during VDT tasks using newly developed equipment that can simultaneously measure pupillary change, focal accommodation and eye movement. The changes in these three physiological measures, taken during a VDT task, were used to propose an index for evaluating visual fatigue. Through multiple regression analysis, an index to describe the psychological sense of visual fatigue was obtained. In this index, the minimum pupil diameter, velocity of focal accommodation for constriction, and width of focal accommodation were included. The results showed that visual fatigue resulting from a VDT task includes not one factor but multiple factors. The index shows that visual fatigue in VDT tasks can be evaluated effectively using both pupil diameter and focal accommodation. This index enables us to assess visual fatigue induced during a VDT task.