Open-loop system of optokinetic nystagmus eye movement in human

The regular optokinetic nystagmus (OKN) is a closed-loop system. Due to the deep negative feedback, OKN response is very stable, and its gain (ratio of eye tracking velocity to stimulus velocity) approximates to 1, even when some lesions occurred in the OKN pathway. The present paper provided a practical method to eliminate the biological feedback loop for examining the inner changes of neuromuscular system. Eye movement velocity was measured in real time and added to the computer generated signal to control the stimulus movement. Thus a constant slip of retina image was achieved and open-loop OKN condition could be accomplished. This electronic approach for OKN open-loop is non-harmful to subject, and it is applicable to medical diagnosis.