Which nystagmus type does not impact Standard Field Sobriety Tests?

Physiological nystagmus is a type of nystagmus that occurs naturally as a response of the eye muscles to various stimuli, such as when someone quickly moves their head or eyes. This form of nystagmus can be observed as a normal and automatic reaction of the eyes, and it does not indicate impairment or intoxication, which is why it does not impact the results of Standardized Field Sobriety Tests (SFST).

In contrast, other types of nystagmus, like Horizontal Gaze Nystagmus and Post Rotational Nystagmus, are often associated with intoxication or neurological issues, thereby affecting the assessment during field sobriety tests. Caloric nystagmus is induced by changes in temperature within the inner ear and may also reveal impairment. Thus, physiological nystagmus remains unaffected in the context of assessing a person's ability to operate a vehicle safely, making it distinct from other types that are relevant to the SFST evaluations.