HGN Eye Field Sobriety Test

Contact Us

OUI Defenses

Operating Under the Influence Laws

HGN (Eye) Test
Breathalyzer Test
Walk and Turn Test
One Leg Stand Test
Alphabet Test

OUI Penalties Overview
OUI DWI First Offense
OUI DWI Second Offense
OUI DWI Third Offense
OUI Conviction



Follow Us on


Criminal Defense Attorney
Civil Attorney

Drunk Driving Defense Massachusetts - Attorney Bristol County, Plymouth County, Norfolk County, Suffolk County, Middlesex County, Worcester County


HGN Eye Test  

In Most Instances Not Admissible in Massachusetts

Horizontal Gaze Nystagmus (HGN) eye test

Massachusetts DUI Lawyer for DUI industry Sobriety Testing and DUI Defense

Horizontal Gaze Nystagmus (HGN) | HGN Sobriety Test | Massachusetts DUI Defense

Horizontal Gaze Nystagmus (HGN) DUI facts

The Horizontal Nystagmus (HGN) Eye Test is 1 of 3 that comprise "Standardized Field Sobriety Tests (SFST) and approved from the National Highway Safety Administration (NHTSA) for DUI standardized testing. The Horizontal Gaze Nystagmus (HGN) eye test. Although scientific studies through the NHTSA information establishes it as a trusted DUI roadside test; some trial courts nevertheless do not allow the admittance of them as evidence. In many cases, the results were argued to be invalid due to weaknesses or error in administration, equipment, and preparations of the HGN test effects were found in many cases to be insufficient to satisfy the court's evidentiary standards. As a result many jurisdictions just allow admittance to establish "Probable cause" pertaining to arrest, or not at all. Due to inaccuracies and arguments as to their validity, they are frequently burgeoning spots of challenge by defense.

Horizontal Gaze Nystagmus (HGN) of the Eye

A Horizontal Gaze Nystagmus (HGN) is an involuntary bouncing, jerking or fast moving of the eye laterally or horizontally, at the juncture the eye gazes from side to side. The NHTSA studies hold that an impaired driver, from alcohol or any other depressant of the central nervous system, is unable to exact or manage their eye muscles. This causes the involuntary movement of the eye. The theory could be that the degree of impairment or the Nystagmus gets greater or more pronounced, as the degree of intoxication or drug effect evolves.

What police are looking for pertaining to in the HGN Test

While administering the test the officer looks for 3 "clues," (or six considering both eyes are tested). The officer will test each eye separately regarding indications of the following:

Lack Of Smooth Eye Rolling Movement;

Certain and Sustained Nystagmus regarding At Least FOUR Seconds;

Angle Of Onset Of Nystagmus.  Without an expert witness it is unlikely a Judge will allow testimony regarding the HGN test. It can't be used against you.


Cell Phone 24 hours (508) 509-5912

Office (508) 583-5454

Email t.tdougherty2@verizon.net


Law Office of Thomas A Dougherty
142 Main St, Brockton, MA 02301