The second clue of the HGN test indicates what specific behavior?

The second clue of the Horizontal Gaze Nystagmus (HGN) test is specifically focused on "distinct and sustained nystagmus at maximum deviation." This refers to observing the eyes when they are turned to the maximum extent to one side, generally at an angle of approximately 45 degrees. When a subject exhibits distinct and sustained nystagmus during this phase, it indicates a potential impairment, often due to alcohol or other substances. This behavior is a key indicator used by law enforcement officers to assess sobriety, as it reveals the physiological effects of intoxicants on the nervous system, affecting eye movement.

Other options, such as involuntary jerky eye movements, rapid eye movement, and blurred vision, are related to eye behavior but do not specifically capture the essence of the second clue in the context of the HGN test. The focus on distinct and sustained nystagmus at maximum deviation provides a more precise criterion for evaluating impairment, making it a crucial component of the standardized procedure.