Which nystagmus refers to jerking when looking straight ahead?

The nystagmus that refers to jerking when looking straight ahead is Horizontal Gaze Nystagmus. This type of nystagmus is specifically characterized by the involuntary jerking movements of the eyes as a person gazes horizontally. It is often used in field sobriety tests to assess impairment, particularly in relation to alcohol consumption.

Resting nystagmus does not pertain to the jerking that occurs while looking straight ahead but is rather a condition where the eyes may exhibit nystagmus when a person is at rest. Vertical Gaze Nystagmus involves jerking movements of the eyes when looking up or down, and it is distinct from horizontal gaze assessments. Involuntary nystagmus is a broad term that refers to any involuntary eye movement, but it does not specifically denote the jerking observed in the horizontal gaze.