Physiological Nystagmus

It is interesting that research indicates that a person’s natural circadian rhythms can affect the results of a nystagmus test, causing an incorrect diagnosis of horizontal gaze nystagmus by an officer. Research in this area suggests that the angle of onset of the twitching or jerking of the eye should be reduced at certain times of the day to be most accurate.

The NHTSA claims that only 3-4 percent of the population would experience this level of nystagmus due to physiological or natural conditions.