Did You Pass the DUI "Eye Test?"

Most people are familiar with the “usual” balancing and coordination field sobriety tests that are given to a driver who has been detained on suspicion of DUI. These tests include “walking the line,” balancing on one leg, and sometimes the finger to nose test. A very coordinated person who is in good physical condition is more likely to “pass” these tests than an individual who is not so advantaged. It is usually apparent to the person performing the test that he or she is passing or failing these tests. However, there is an additional DUI test that is almost always given in Washington State DUI arrests where successful performance is not apparent to the DUI suspect – the “eye test.” The eye test consists of an officer requiring the DUI suspect to track a stimulus, usually a pen or a small flashlight, that is moved back and forth in front of the suspect’s face. The DUI suspect will often believe that he or she has “passed” the test because they were able to watch the stimulus as it was moved back and forth. However, the officer is looking for something that the DUI suspect cannot see or feel – the jerking of the eyeball as it tracks that is otherwise known as “Horizontal Gaze Nystagmus,” or HGN. The theory is that onset of the jerking is associated with consumption of alcohol and there are law-enforcement sponsored studies that, not surprisingly, back up this claim. The officer is attempting to discern, at night and in field conditions, whether the “onset” of the bouncing occurs before or after a 45 degree angle. There are a number of non-alcohol related causes for Horizontal Gaze Nystagmus and numerous obstacles prevent accurate measurement of the 45 degree onset angle in the field as opposed to in the laboratory of an ophthalmologist. As with the other field sobriety tests, the determination of a “pass” or “fail” is completely subjective on the part of the officer. In cases where the DUI suspect’s performance is recorded by in-car police video, the jury will be able to make their own assessment about the DUI suspect’s performance on the balance and coordination tests. However, no video is taken that is capable of revealing the tracking of the subject’s eyes when following a stimulus during the DUI HGN test. Therefore, the jury will have determine whether to take the officer’s word regarding the eye test, or take the citizen’s word that he or she did, in fact, “pass” this DUI test.