Which type of nystagmus is characterized by involuntary jerking as the eyes gaze sideways?

Horizontal Gaze Nystagmus is a specific type of nystagmus characterized by involuntary jerking of the eyes as they gaze sideways. This phenomenon occurs when the eyes attempt to follow a moving object from side to side, and the jerking motion is particularly noticeable when the eyes are at the extreme lateral positions.

The identification of Horizontal Gaze Nystagmus is significant in clinical and law enforcement settings, especially in the context of sobriety tests, as it can indicate impairment due to substances such as alcohol or drugs. Its manifestation usually occurs when the eyes reach the outer limits of their movement, where they may not smoothly follow the target, leading to periodic jerking.

In contrast, Vertical Gaze Nystagmus involves similar involuntary eye movements but occurs when the gaze is directed up and down. Resting Nystagmus relates to the eyes appearing to beat or drift even when a person is not moving their eyes intentionally, and Involuntary Gaze Nystagmus is a more general term that does not specify the direction or mechanism of the eye movement. Therefore, Horizontal Gaze Nystagmus is the accurate term for the situation described in the question.