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What is the horizontal gaze nystagmus test?

| Sep 13, 2017 | drunk driving defense |

Prosecutors rely on a wide variety of evidence when trying to obtain a drunk driving conviction. Of course, they will attempt to admit evidence regarding breathalyzer test results and officer accounts of a driver’s behavior, but that’s not all. They also often have police officers testify about field sobriety tests that may have been administered to a driver. The results of these tests can be seriously damaging to a defendant, meaning that he or she could wind up facing serious penalties as a result.

One field sobriety test that is often used is the horizontal gaze nystagmus test. This test is administered by an officer who holds up his or her finger about a foot in front of the test subject. The finger is then slowly moved from side-to-side while the subject follows it with his or her eyes, but while holding his or her head steady. There are essentially three things an officer is looking for that can be indicators of intoxication.

First, an officer can analyze the subject’s eyes to determine if they can smoothly follow the officer’s finger. If there is a jerk to the eye’s movement, then an officer may consider that an indication of intoxication. Second, an officer will look to see if the eyes start to jerk once reaching a 45-dgree angle. Lastly, an officer will likely hold his or her finger all the way to the side for a period of time to see if, shortly after looking all the way to the side, the test subject’s eyes start to bounce.

Although this test is a common feature of drunk driving prosecutions, the truth of the matter is that it is not always accurate. In fact, some studies indicate that it only detects intoxication about 75 percent of the time. Additionally, police officers don’t always conduct these tests in accordance with applicable standards. Therefore, simply because an individual has failed a field sobriety test does not mean that he or she should not try to craft a compelling criminal defense. Instead, he or she should think about discussing his or her case with a competent criminal defense attorney.