What does the term “nystagmus” refer to in field sobriety tests?

Answer: C — The involuntary jerking of the eyes that can indicate intoxication

The term “nystagmus” refers to the involuntary jerking of the eyes, a phenomenon that can be indicative of impairment, particularly due to intoxication. During field sobriety tests, officers often look for signs of nystagmus when assessing a driver's level of impairment. This is because alcohol and certain drugs can affect the vestibular system, leading to this involuntary eye movement. Nystagmus can be observed and evaluated through a test known as the Horizontal Gaze Nystagmus (HGN) test, where an officer asks a suspected driver to follow a stimulus, such as a pen or flashlight, with their eyes. If the eyes exhibit jerking movements at certain angles, it may suggest that the individual is under the influence of alcohol or drugs. While cognitive tests and coordination tests are also relevant in assessing sobriety, they do not specifically involve eye movement assessment. A breathing test, like a breathalyzer, measures blood alcohol concentration rather than physical indicators like nystagmus. Thus, understanding the specific definition and implications of nystagmus is crucial in the context of field sobriety tests.