Texas Horizontal Gaze Nystagmus Testing
In order to determine probable cause for a driving while intoxicated (DWI) arrest, Texas law enforcement agents administer a series of field sobriety tests. These tests consist of the horizontal gaze nystagmus test, the one-leg stand test, and the walk-and-turn test. Out of the standardized field sobriety tests, the horizontal gaze nystagmus is considered to be the most scientific if administered properly.
The National Highway Traffic Safety Administration developed the guidelines for the field sobriety tests. Law enforcement agents should follow these guidelines and remain consistent when administering the tests.
Horizontal gaze nystagmus is an involuntary jerking of the eye that occurs when a person looks to the side. Intoxication may cause this jerking to become more notable.
During the horizontal gaze nystagmus test, the officer will ask you to follow a small stimulus, such as a pen, with your eyes. The officer will then look certain “clues,” such as the onset of jerking before reaching a 45-degree angle, inability to smoothly follow the stimulus with your eyes, and sustained jerking when your eye is at the furthest point.
The officer will look for these three clues in each eye, for a total of six. If the officer observes four or more clues, it could be assumed that your blood alcohol content (BAC) is over the legal limit.
Because it is considered the most scientific form of field sobriety testing, failing the horizontal gaze nystagmus test could hurt your case. An attorney who is familiar with field sobriety testing can help you challenge the results of this test.
A major problem with this test is that there are numerous physical conditions that can cause nystagmus, such as eye ailments, brain tumors, and medication. Because officers lack medical education, they may not know the underlying cause of the nystagmus. Your attorney may investigate your horizontal gaze nystagmus test to determine if it was caused by something other than intoxication.
Attorney Ken Gibson has completed the same NHTSA field sobriety testing course as Texas law enforcement agents. Thanks to his knowledge of field sobriety testing, he has a successful record of winning DWI cases or having them reduced to a lesser charge. To fight your pending charges, please contact Mr. Gibson today.