Horizontal Gaze Nystagmus | HGN Test

One of the most common field sobriety tests administered by law enforcement officers following suspected DUI in Utah is the Horizontal Gaze Nystagmus or “HGN” test. Some people commonly refer to this test as the “follow the pen” test. When an officer administers this test, typically after suspecting drunk driving or in some cases following minor consumption of alcohol, the officer will first check for equal tracking of your eyes by moving the pen or other object side to side. Next the officer will typically check your eyes for equal pupil size. At the time the officer is checking for equal pupil size, he will typically hold the pen right in front of your face and will also be checking for resting nystagmus. Nystagmus essentially means a jerking of the eyes. The video below demonstrates what nystagmus actually looks like. Next the officer will again move the pen from left to right repeating this motion checking for a lack of smooth pursuit. The officer will also check for nystagmus at maximum deviation. Which means checking to see if the eyes of the defendant twitch back and forth when looking all the way to the side. Another clue is nystagmus prior to 40 degrees. Vertical nystagmus occurs when the eyes are tracking up and down. All of these clues are demonstrated in the video provided below:

Provo Utah DUI Attorney

If you were pulled over and asked to perform field sobriety tests, it is very likely you were asked to perform the HGN test described above. At our office, we look at the details of how these tests were performed to ensure any mistakes made by the officer in collecting this evidence against you is properly addressed in court and before the jury if necessary. A Provo Utah DUI Attorney at our defense law firm can help to ensure your rights are properly protected and that officers are kept honest in the way they perform these tests and testify against you. For more information, contact us today.

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