Mental fatigue has been lacked attention in developing eye-tracking fatigue detection system for drivers. However, it has great influence on eye movement which could account for the poor validity of current fatigue detectors only focusing on sleep-related fatigue. This work sought to investigate the influence of two types of task-related mental fatigue on eye movement by examining 8 saccade-based, 3 blink-based, and 1 pupil-based metrics. We propose that two types of task-related fatigue caused by cognitive overload and prolonged underload will induce different physiological responses to eye-motion features. Twenty participants completed a vigilance task before and after a 1-h driving with a secondary task in a virtual simulation environment, while forty participants, divided equally into two groups, finished the same task before and after a 1-h and 1.5-h monotonous driving. T-test was applied to analyse the eye-motion, subjective and vigilance data during vigilance task. We found that overload driving made drivers vigilance ability decrease. The eye metrics showed different changes in underload and overload scenario. The blink duration, the mean velocity of saccade and saccade duration increased after 1-h overload driving, while the pupil diameter decreased. However, none of those changes were observed in 1.5-h underload driving, but saccade duration had a significant increase. The fatigue response to heavy demands over short periods of driving is different from the lighter demands over long periods in terms of eye-motion metrics. Considering mental fatigue in designing an eye-tracking fatigue detection system could possibly improve its accuracy.

在开发用于驾驶员的眼动疲劳检测系统中，精神疲劳一直缺乏关注。然而，它对眼睛的运动有很大的影响，这可以解释目前仅关注与睡眠有关的疲劳的疲劳检测器的有效性差。这项工作试图通过检查基于8个扫视，三个基于眨眼和1个基于瞳孔的指标来调查两种与任务相关的精神疲劳对眼睛运动的影响。我们提出，由认知超负荷和长期负负荷引起的两种与任务相关的疲劳将引起对眼动特征的不同生理反应。在虚拟仿真环境中，有20名参与者在进行1小时驾驶之前和之后完成了一项警戒任务，并完成了次要任务，而40名参与者则被平均分为两组，在1小时和1.5小时单调驾驶前后都完成了相同的任务。采用T检验对警戒任务期间的眼动，主观和警戒数据进行分析。我们发现，超载驾驶会使驾驶员的警惕性降低。眼图指标显示了在欠载和过载情况下的不同变化。1 h超载驾驶后，眨眼时间，平均扫视速度和扫视持续时间增加，而瞳孔直径减小。但是，在1.5小时的欠载驾驶中，没有观察到这些变化，但是扫视时间有明显增加。就眼动指标而言，在短期驾驶中对高要求的疲劳响应与长期中较轻的要求不同。