When drivers are pulled over for the suspicion of drunk driving, the officers will sometimes conduct a standardized field sobriety test. One of the components of this test is the horizontal gaze nystagmus test.

There is a good chance that you’ve seen this test administered on television or in the movies. This is the test involves the officer asking the person to use their eyes only to follow a pen or light from left to right and up and down. When the person is doing this, the officer is watching for certain actions by the eyes.

When you look from left to right or up and down, your eyes move smoothly. A person who is intoxicated will have jerky eye movements. These jerks are what the officer is checking for when conducting the test.

Just like other components of a drunk driving test, the horizontal gaze nystagmus test is highly controversial. One reason for this is that the test is largely subjective. Sometimes, the test comes down to how the officer interprets the test.

It is also possible that the test result is skewed by another factor. Eye fatigue or strain, for example, can cause the eyes to behave in the same manner as the eyes of a person who is impaired. This fact is something that can come up in a defense strategy if there are the correct elements to do so. We can help you determine which options you have for a defense. Once you make a decision about the direction, we can help you get your strategy moving forward.

Source: FindLaw, “What Is Horizontal Gaze Nystagmus (HGN)?,” accessed Feb. 09, 2018