Relation between human alertness, velocity wave profile of saccade, and performance of visual activities

Practical method for assessing human alertness is desired for preventing traffic accidents caused by drowsiness in the drivers. We examined relation between saccade profile (PV/D), which was reported to have dependency on the alertness, and visual activities to investigate an applicability of the saccade for assessing the alertness in vision-dependent circumstances such as driving. We defined a new parameter of visual activity as "bit rate of visual perception (BRVP)", and analyzed relations of saccade velocity profile to the BRVP, relative pupil diameter, and critical fusion frequency. The results showed significant high positive correlations between PV/D, BRVP, and relative pupil diameter.