Alcohol gaze nystagmus (AGN) is a temporary condition that is the result of the ingestion of alcohol or nervous system depressants of any form. The condition causes the eye to involuntarily jerk or bounce due to the fluid imbalance that occurs in the inner ear. The inner ear controls the motor system of the human eye.
Alcohol Gaze Nystagmus Explained
The test for alcohol gaze nystagmus is one of the three tests that are commonly used by U.S. law enforcement officers to determine whether or not a person is intoxicated. In order to perform this test, a law enforcement officer asks a suspected offender to focus on the officer's extended finger or a pen placed about six inches from the suspect's face. The officer will then move the object from left to right while watching the suspected offender's eye movement. If jerking or bouncing movements occur in the eye before the eye reaches a 45-degree angle, then the individual is deemed to have failed the test.