The demand for measurements of mental stress and fatigue, which leads to low efficacy, illness, and sometimes tragic accidents, is rising up in recent years. However, detection and quantification of change in one's wakefulness which trigger mental stress and fatigue remains to be elucidated. In this paper, we focus on physiological signals showing up on one's eyelid to detect change in one's wakefulness. Using our micro-fabricated eyeglass-shape optical sensor system, we successfully found several eyelid movements which have strong correlation with one's wakefulness. It was experimentally revealed that blink burst rate is strongly associated with subjective mental fatigue. These findings demonstrate that we can evaluate subject's change in one's wakefulness using our glass-shape optical sensor.