During the Horizontal Gaze Nystagmus (HGN) test, which eye is tested first?

In the Horizontal Gaze Nystagmus (HGN) test, the left eye is typically tested first to maintain consistency in the testing procedure. This standardization helps to ensure that the results are reliable and can be compared accurately across different tests and subjects. By starting with the left eye, the officer can assess the presence of nystagmus (involuntary eye movements) in a systematic way, which aids in evaluating the subject's level of impairment.

This order also aligns with some procedural guidelines used by law enforcement to ensure that the test is administered uniformly. Starting with one eye helps to minimize any potential biases in observing reactions between the two eyes, providing a clearer picture of the subject's eye movement responses.

While the other choices may imply different methods of conducting the HGN test, the accepted practice is to start with the left eye consistently. Hence, the choice indicating that the left eye is tested first accurately reflects the proper procedure for administering the test.