What is the maximum number of clues for the Horizontal Gaze Nystagmus that can appear in one eye?

The maximum number of clues for the Horizontal Gaze Nystagmus (HGN) test that can appear in one eye is three. During the HGN test, the officer looks for specific clues related to eye movement in response to a stimulus (such as a pen light). These clues include the inability of the eye to follow a moving target smoothly, a distinct nystagmus at maximum deviation, and the onset of nystagmus prior to 45 degrees.

Each of these indicators provides significant observations about the subject's level of impairment. When eyes are examined together, the maximum number of indicators or clues from both eyes cumulatively can help in assessing potential alcohol or drug impairment. The three clues per eye are critical for establishing a subjective measure that may support the officer's conclusion on the individual's sobriety.