Sometimes when you are stopped by law enforcement officers in Massachusetts, you may be asked to perform field sobriety tests. While you may be familiar with tests that require standing on one leg and walking and turning, you may not have heard about the horizontal gaze nystagmus.

The horizontal gaze nystagmus test is one way that law enforcement officers can determine if you might be inebriated. FindLaw says this is because this test considers involuntary eye movements. When you look to one side, sometimes your eyes automatically jerk. If you have been drinking, this jerking may sometimes be more pronounced. You usually do not realize that your eye is moving more because this phenomenon typically does not affect your vision. This eye jerking can occur because alcohol sometimes affects the way your nervous system manages eye movements.

The horizontal gaze nystagmus test is usually simple. Most of the time, you will be asked to follow the path of an object with your eyes. Law enforcement officers generally want to see if your eyes begin jerking if you look to the side for more than four seconds and if your eyes can follow the object without jerking. You may not think that this kind of test can determine if you are intoxicated. However, this test is usually more accurate than other kinds of field sobriety tests.  

If law enforcement officers think that you have been drinking too much, the horizontal gaze nystagmus is generally not the only test you will be asked to perform. You may also need to perform other field sobriety tests, and law enforcement may sometimes ask you to take a breath test as well.

This information is intended to educate and should not be used in place of legal advice.