Abstract
It is well known that decline of arousal level causes of poor performance of movements or judgments, while doing VDT work, driving cars, and so on, and also reduces productivity and safety. Previous studies show the slow eye movements (SEM) could be a candidate for an indicator of decline of arousal. However, since SEMs appear just prior to sleep onset, it is not sufficient to evaluate transition of arousal states. In this study, we examine the effects of the transition of arousal on microsaccade rate and pupil fluctuation while subjects are continuously gazing a fixation crosshair. The subjects are instructed to indicate by mouse-licks when they are aware of having slept. The eye movement and pupil fluctuation data are analyzed for the former period from SEMs, which are detected immediately before the mouse-clicks. The results show that longitudinal miosis of pupil diameter and gradual rise of microsaccade rate are observed in advance of the occurrence of SEMs. These resu Its suggest that the arousal level could be evaluated by monitoring eye movements and pupil fluctuations.
