Your Guide to the Horizontal Gaze Nystagmus Test

December 11, 2020

DUI is taken very seriously in the state of Virginia. If you are pulled over for DUI, you should take it seriously. The officer who stops you will likely administer a range of tests to determine your sobriety. The Horizontal Gaze Nystagmus is one of the three standardized tests developed by the National Highway Traffic and Safety Administration (NHTSA) to do this. Supposedly, research has shown that the test has a 77% accuracy rate in detecting BAC levels of .10 and higher.

The word Nystagmus refers to the involuntary jerking of the eyeball. An officer who administers this test will look for an involuntary horizontal jerking movement when the suspect focuses on a stimulus moving from side to side. This jerking phenomenon can be traced to alcohol or drug use, which has the effect of depressing the central nervous system. When the central nervous system is depressed, the brain loses its ability to fully control eye muscles. The more alcohol there is in a person’s blood system the more marked the nystagmus.

How Police Officers Administer the Nystagmus Test

If you are stopped by a law enforcement official and they decide to carry out a nystagmus test, you can expect the following things to occur.

The officer will instruct you to stand up straight and face them. They will then position a stimulus (usually their pen or an index finger) 12 to 15 inches from your face. Typically, an officer is supposed to conduct a pretest for resting nystagmus and equal pupil size to ensure that you do not exhibit nystagmus that may be unrelated to alcohol or drug consumption. Following this, you will be instructed to follow the tip of the stimulus with your eyes and eyes only, not moving your head or body. The officer will then move the object from one side to another and observe your eye movements. The officer is looking for 3 possible indicators in each eye: lack of smooth pursuit, distinct and sustained nystagmus at maximum deviation (extreme periphery), and onset of nystagmus prior to 45 degrees. If the officer observes jerking movements at the relevant times for these indicators, he will make a note of it.

The Problem with the Nystagmus Test

Although the theory behind the test is sound, the skills of the officers who use it vary. Indeed, the main problem with the use of the test is that officers do not have medical or scientific training to make an accurate diagnosis. Many officers, though instructed on how to offer the test, fail to administer it to the requisite scientific standards. Moreover, there are over 60 forms of naturally occurring nystagmus that any given subject could be exhibiting that have nothing to do with alcohol or drug consumption.

Your Right to Challenge the Results of a Nystagmus Test

The penalties for a DUI conviction in Virginia are quite severe. If an officer has used a nystagmus test to arrest and charge you with DUI, you have a right to challenge them. You have a great deal at stake, and it is right for you to hire a DUI attorney Fairfax County or DUI attorney Arlington County from Rudolphi Law and to dispute the accuracy of the test and the credibility of the officer.

Being charged with a DUI does not mean you are guilty of this crime. The state must still prove its case. The DUI lawyer Fairfax County or DUI lawyer Arlington County from Rudolphi Law that you hired will examine each step that the officer took to charge you with DUI. They will scrutinize the reasons you were stopped and the officer’s interaction with you once you pulled over.

If the officer used the nystagmus test, the DUI attorney Fairfax County or DUI attorney Arlington County you hired will look at the training they received to conduct it. There is no reason to assume that all officers have received the same quality of training. Fairfax County DUI lawyers and Arlington County DUI lawyers at Rudolphi Law represent their clients with integrity and effectiveness. If you have grounds for challenging the DUI test used to charge you with this crime, you should speak to a Fairfax DUI lawyer or Arlington DUI lawyer at Rudolphi Law.