The National Highway Traffic Safety Administration (NHSTA) has developed three standardized field sobriety tests that are used to evaluate intoxication; among these is the horizontal gaze nystagmus. Like any field sobriety test, the horizontal gaze nystagmus test is not without its flaws, and its administration should be reviewed by an experienced operating while intoxicated (OWI) defense attorney to determine if it can be challenged.
The medical term used to describe the involuntary shaking of the eyes, nystagmus often becomes more pronounced after a person is under the influence of alcohol and/or drugs. During the horizontal gaze nystagmus test, an officer will ask you to keep your head still and follow a small object, such as a penlight or even his or her finger, with your eyes in order to evaluate nystagmus and determine if there is probable cause to make a drunk-driving arrest.
While you are performing this test, the officer will look for three clues in each eye, for a total of six clues altogether. These include lack of smooth pursuit, jerking before reaching 45 degrees (between your nose and shoulder), and distinct jerking while your eyes are all the way to the side. Officers almost always determine that subjects exhibit enough clues to be placed under arrest for OWI.
While nystagmus may be a sign of intoxication, it’s also a symptom of more than 100 medical, neurological and optical conditions. Some of the most common causes include head trauma, inner ear diseases, brain tumors, medication (such as anti-seizure medicine), and even vitamin deficiencies. Because the officer is not a trained medical professional, he or she cannot tell the difference between nystagmus caused by alcohol and nystagmus caused by a preexisting health condition.
Your attorney may work with your doctor to determine if you have any conditions that would have caused you to fail the horizontal gaze nystagmus test. If this is the case, your doctor could be asked to testify on your behalf.
This test must also be administered correctly for the results to be deemed valid. If the officer did not keep enough distance between your eyes and the stimulus—or moved the penlight too quickly—your attorney can challenge your test score.
At Tracey Wood & Associates, our attorneys have undergone training on the field sobriety tests, and understand the potential defenses that can be used to help your case. Attorney Tracey Wood has been trained as an instructor in field sobriety tests even. For more information on how we can fight your charges, please complete our online form now to set up a no-obligation consultation.