The pseudo-science behind standardized field sobriety testing is further complicated when instructions and demonstrations are communicated to the driver in a manner inconsistent with NHTSA guidelines. Standardized field sobriety tests were developed in a lab where participants were not subjected to potential criminal penalties based on natural human reactions to fear misinterpreted as clues of impairment by police officers. Participant performance in a lab setting was not negatively impacted by psychological or physiological responses to the fear of instant incarceration as a consequence of failure, instant unemployment as a consequence of a failure, and the embarrassment of being the subject of a police investigation on a public roadway.

Nystagmus is an involuntary bouncing or jerking of the eye. Sometimes called the "Pen Test," the Horizontal Gaze Nystagmus Test was developed to identify nystagmus in the eyes of drivers under investigation for driving under the influence. Nystagmus is a common side effect of substances such as nicotine, caffeine, and aspirin, but it can also be a side effect of impairment from illegal drugs or alcohol. It's beyond absurd to believe everyone who displays nystagmus in the eyes is impaired. 

The HGN test begins after the police officer checks the driver’s eyes for equal pupil size and equal tracking. Most drivers will display equal pupil size and equal tracking unless there has been a traumatic brain injury. The real reason police are trained to check for equal tracking and equal pupil size is to project an illusion of integrity on an unfair test. The odds of being the victim of a traumatic brain injury are extremely slim, while lots of people use common non-impairing substances like caffeine, nicotine, and aspirin. 

The police officer will begin the HGN test by instructing the driver to identify a stimulus (e.g., pen, finger, or flashlight) 12 to 15 inches away and slightly above the driver's eye level. The driver will be instructed to follow the stimulus with the eyes and eyes only, without moving the head, as the officer moves the stimulus from side to side in the driver's field of vision. 

A police officer conducting the Horizontal Gaze Nystagmus test will check the driver's eyes for three clues of nystagmus.

1. Lack of Smooth Pursuit: Does the eye follow the stimuli smoothly as it moves from the center of the face toward the ear, or is there an involuntary bouncing or jerking present?

2. Distinct and Sustained Nystagmus at Maximum Deviation: Does the pupil have a distinct and sustained bouncing or jerking motion after being held toward the outer edge for four seconds? 

3. Onset of Nystagmus Prior to 45 Degrees: As the officer moves the stimuli toward the edge of the motorist's shoulder, is there an involuntary bouncing or jerking present in the pupil of the motorist before the object is at a 45-degree angle from the center of the suspect's face?

The only instruction given to a driver tested for gaze nystagmus is to follow the stimuli (e.g., pen, finger, or flashlight) with eyes only and without moving the head. Police are not trained to disclose the hidden criteria of the Horizontal Gaze Nystagmus test. Almost anyone can follow a stimulus (e.g., pen, finger, or flashlight) with eyes only and without moving their head, leaving most drivers to believe they passed the HGN test. But it’s nearly impossible to pass the HGN test as common substances like caffeine, nicotine, and aspirin also cause nystagmus, and it's beyond absurd to believe a driver who displays nystagmus in the eyes is impaired.

A DUI conviction will have negative consequences for professional and educational opportunities long after sentencing and DMV penalties have expired. DUI Defense Attorney Travis Newton defends clients charged with driving under the influence in the Upstate Summary and General Sessions Courts (Anderson, Clemson, Seneca, Easley, Pickens, Greenville. If arrested or questioned by police, it is important to remain silent and contact a criminal defense attorney or DUI lawyer as soon as possible. Travis Newton has been Lead Counsel Verified for DUI Defense by Thomson Reuters for ten consecutive years and is a founding member of The American Association of Premier DUI Attorneys. A consultation with DUI Lawyer Travis Newton will provide answers that can lead to informed decisions on how to proceed.

Travis Newton Law Firm. 513 North McDuffie Street Anderson, SC 29621 Free Consultation (864) 965-9148.

Travis Newton DUI Defense Attorney

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Travis Newton Law Firm

Anderson, S.C. DUI Lawyers

Travis Newton Law Firm 513 North McDuffie Street Anderson, SC 29621