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California DUI Investigations: What Every Officer Looks For

Horizontal Gaze Nystagmus is a hard way of saying that the testing officer is looking for an involuntary jerking or bouncing of the eyes as they are moved from center to the side of your field of vision.  This test is administered during a dui investigation while the officer is facing you and, if dark, he is using an indirect light source like a flashlight.  The officer will usually tell you “I am going to check your eyes.  Keep your head still and follow my pen with your eyes only.  Keep following my pen until I tell you to stop.”

Officers have been told they are to look for three things in the administration of this DUI test.  Before conducting the test the officer will insure the eyes of the subject are tracking.  If the eyes are not tracking the test cannot be conducted.+

During this impairment test officers are to look for:

  • A lack of smooth pursuit in the eyes. Your eyes can be observed to jerk or bounce as they follow a slowly moving stimulus. (Many times a pencil or pen, sometimes a finger though it is not preferred.) Theoretically your eye will follow the stimulus in a smooth fashion and will not bounce or jerk if there is an absence of alcohol until it reaches extremes.
  • The second clue officers are trained to look for is sustained bouncing at maximum deviation in excess of 4 seconds. (Most all people will display a jerking of the eye at maximum deviations but alcohol theoretically is more pronounced and lasts for more than a few seconds.)

If the point at which the eye is first observed jerking is prior to 45 degrees it is believed the nystagmus will be observed sooner.  (Some studies suggest an officer may be able to predict a specific alcohol level by using this test.  No Court I am aware of has allowed the prediction of a specific alcohol level from the bouncing of the eyes.  The general scientific community does not accept this theory and until it does no court will admit that kind of guesswork.  (Kelly/Feye)

This test, though used by the trained Doctors in a darkened room, is now used by officers in DUI investigations.

A Failed Impairment Test Does Not Equal a DUI

Ronald MacGregor, partner at MacGregor & Collins, LLP, believes that this test and its findings could be considered inadmissible.

“First, officers do not administer the test properly.  Therefore, the test qualifies for the “junk in junk out” analysis.  Many officers have you perform this test while you are still seated in your car.  Oops.  The officer is not standing in front of you and you have your head turned.  (improper administration).  The officer must hold the stimulus a certain distance away from your eyes and slightly elevated.  He must make a number of passes testing each eye and when you reach the extreme of each eye he must hold the stimulus for a period of four seconds and he cannot move the stimulus too far.

You must keep your head still and follow the stimulus with your eyes only.  In every police report I have read the cop will have the suspect swaying if not in a circular motion then either forward to backward or side to side.  If your body is swaying as indicated by this police observer then your head is moving.  If your head is moving the test is administered improperly and invalid.  Eyeglasses are to be taken off for the performance of this test.  Guess how many officers don’t ask you to take off the glasses and don’t inquire if you have contacts?  Invalid.  A certain number of people  (about 3%) have nystagmus naturally and if that isn’t enough there are 36 other medical conditions that will display nystagmus and alcohol is only one of them.

Others can be:  Problems with the inner ear;  influenza;  vertigo;  measles;  epilepsy;  hypertension;  motion sickness;  sunstroke;  eyestrain;  glaucoma;  eye-muscle fatigue;  aspirin;  excessive amounts of caffeine or nicotine; diet;  toxins;  heredity;  continuous movement of the visual field past the eyes;  (If your being tested and your facing the traffic at night that is a visual field;  Officers flashing lights is a visual field.)  There are many more,” said DUI attorney MacGregor.

Whether or not it will be held against you in a court of law, driving while under the influence is extremely dangerous and could lead to catastrophic injuries or death. Next time, make the responsible decision and avoid drunk driving.

For more information about California DUI arrests and/or convictions, take a look at this infographic: http://ow.ly/hgKGy.


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