Eye blink is an essential eyelid movement that helps spread tears, and keep our vision clear. During a blink, there is no visual input and no light, but we do not consciously recognize everything has momentarily gone dark. It is known that some patients with neurological disorder, including Parkinson's disease, have impairments of eye blink, large eye movements, and small fixational eye movements. In addition, previous study suggested that, these fixational eye movements are sensitive to fatigue, sleepiness, and motor preparation. We analyzed fixational eye movement around voluntary and involuntary eye blinks.
We recorded eye movement of healthy adult human subjects using a high-speed video camera based eye tracking system, and detected eye movement and blink. In order to control preparatory state, the subjects were instructed to produce a voluntary eye blink with acoustic tone signals or to keep viewing in the display with free eye blink.
We found following two things. First, before the voluntary eye blink, rate of fixational eye movements gradually decreased, but increased before the involuntary eye blink. These findings suggest that fixational eye movements may be influenced by motor preparation of the eye blink. Second, after the eye blink the eyes were misaligned by the movement of the eyelids, however corrective fixational eye movements retracted the eye position back to the previous gaze point. This corrective eye movements may contribute successive recognition of our vision.