Law enforcement officers must follow strict procedure when conducting horizontal gaze nystagmus tests. Most motorists are uninformed of these guidelines and are therefore unaware that the arresting officer may have conducted their test incorrectly until they consult a Graham DUI lawyer.
The Purpose of the Horizontal Gaze Nystagmus Test
Police officers routinely perform horizontal gaze nystagmus tests on drivers suspected of alcohol intoxication to examine motorists’ eyes for nystagmus, or erratic eye movements that may signify intoxication. One weakness of the test is that, as Graham DUI attorneys can attest, nystagmus naturally occurs in some individuals. That said, the test process can be broken down into multiple steps.
Preparing for the Test
Before administering the test, police officers often request that suspects prepare. They may ask motorists to:
- Remove any facial obstructions, such as eyeglasses, although a Graham DUI lawyer may argue that this weakens the suspect’s ability to perform the test
- Relax their arms at their sides
- Stand with their feet together
- Remain motionless
Graham DUI Attorneys on the Conducting of the Test
When preparation is complete, the law enforcement agent will produce a small object, typically a small flashlight or pencil, and begin administering the test. He or she will most likely:
- Hold the object far enough away from the suspect’s face to be easily visible
- Instruct the suspect to track the path of the object with his or her eyes
- Slowly move the object side to side several times
A Graham DUI Lawyer Discusses Observing Eye Movement
The most important portion of the test is the observation portion, as any interpretations of nystagmus may lead to a suspect’s arrest. During the observation phase, the test administrator will be certain to:
- Observe the suspect’s pupil size
- Watch for erratic eye movements
- Record all instances of nystagmus
A police officer might also ask a suspect to complete a vertical nystagmus test, although Graham DUI lawyers do not see this as often as horizontal gaze nystagmus tests.
If you have been arrested for DUI and believe that the arresting officer did not follow correct horizontal gaze nystagmus procedure, the Graham DUI lawyers from Greene & Lloyd PLLC may have the resources to help. Contact them now at (253) 770-0808.