Was the Officer Qualified to Conduct the HGN Test?
One of the tests that police officers use when making DUI determinations is the horizontal gaze nystagmus (HGN) test. This test specifically examines a person’s eye movements.
To perform the test, an individual (with one eye closed), focuses the other eye on a pencil-sized beam of light that comes from a pocket flashlight that the police officer holds. Once the officer moves the beam from left to right and vice-versa, the normal response is a jerking movement of the eye as it follows the beam of light that will take place once the light beam has reached a deviation of 40° or more. The presence of alcohol in one’s system is said to cause these deviations to take place at lesser angles.
An experienced Orange County DUI attorney will tell you that the HGN test is a type of ophthalmologic examination that requires a person to have extensive experience in recognizing the degree at which the actual deviation takes place. There are a wide variety of potential eye and neural disorders (as well as a lot of drugs) that can affect the results of the test.
Here is a short example of an Orange County DUI attorney’s cross-examination of an officer regarding the HGN test:
Q: Officer, is it true that you have been trained in the horizontal gaze nystagmus test?
Q: The HGN test is actually an ophthalmological exam, right?
Q: You are not an ophthalmologist, officer, are you?
Q: You haven’t had any special training in ophthalmology, have you?
Q: As part of your HGN training, were you told that there are many potential eye disorders that can affect the test results?
Q: However, you are not qualified to determine whether or not Mr. Smith had, or has, any eye disorders, are you?
Q: Yet eye disorders can affect the HGN test results, correct?
A: I believe so.
If you need an Orange County DUI attorney, call Mike Coffey for a free consultation.