Horizontal Gaze Nystagmus

There are three different Field Sobriety Tests recognized by Nevada courts. The Horizontal Gaze Nystagmus is the most reliable out of the three, with a 70% accuracy. You can read about the other two here; One-legged Stand and the Walk-and-turn.

The HGN is an eye test performed to see if the driver’s eyes display nystagmus, which means an involuntary jerk of the eye, following a stimulus. A nystagmus indicates the driver has been drinking.

The test is usually administered within half an hour of the initial stop. Any contact lenses or glasses will be removed. The police officer will stand in front of the suspect and hold up a pen or finger (the stimulus), 12-15 inches from the suspect’s face. The suspect is instructed to keep the head still and follow the stimulus with the eyes only.

The officer will look for three different clues

  • Are the suspect’s eyes jerking while the stimulus is moved from side to side?
  • While at the maximum deviation (eyes turned as far out as possible), how much do the eyes jerk involuntarily?
  • Do the eyes display nystagmus prior to reaching a 45-degree angle?

Both eyes are checked separately, which means that there are 6 different clues, 3 per eye. Displaying 4 or more clues is a failing HGN score.

If the suspect, in addition to failing the HGN test, display other signs of intoxication, he or she will be arrested for DUI. Your experienced DUI attorney will look at a range of circumstances, to have your case reduced or possibly dismissed altogether.

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