What is the maximum number of clues for HGN that can appear in one eye?

In the context of Horizontal Gaze Nystagmus (HGN) testing, each eye can display up to three distinct clues that indicate impairment. These clues include:

1. The onset of nystagmus prior to a 45-degree angle.

2. The maximum deviation of nystagmus, where it is visibly observable.

3. The ability to maintain a steady gaze at that maximum deviation.

As a result, if only one eye is examined, it can show up to three clues, reflecting a level of impairment that can be assessed through this specific eye movement behavior. Understanding the significance of each clue is essential for evaluating a person’s condition effectively during impaired driving assessments.