The Horizontal Gaze Nystagmus Test (HGN)

Interviewer: Let’s talk about the standard tests that are administered, beginning with the horizontal gaze Nystagmus test. What does that consist of and what are the police looking for during that test?

Alcohol Consumption, as Well as Numerous Other Factors, Can Cause Involuntary Eye Movement

Steve Tomeo: They are looking for an involuntary movement of the eye because alcohol consumption can cause this involuntary movement, which I guess is true. On the other hand, there are other things that call horizontal gaze Nystagmus. If you ask a doctor, there are all sorts of factors that can cause this.

There Is a Standardized Method of Instruction for the HGN Test

The individual is given a series of instructions with regard to this test. In Connecticut, the police officer can give the test and report what he sees in the test itself. He’s supposed to administer this particular test in a standard way.

He’s supposed to ask number of questions which are number one, I’m going to check your eyes and at this point just please remove your glasses. Number two, just keep your head still and follow the stimulus with your eyes only. Do not move your head and do you understand the instruction?

Then he’ll move the stimulus, which could be his finger or a pen or some kind of a penlight that’s held 12 to 15 inches away from your face. It is held a little bit above eye level and he moves it from a standard position to the right back to the center position then to the left. He’s checking to see whether or not there is what they call equal tracking of the eyes, that is are both of the eyes moving in sync with one another.

He’s also checking as to whether the fluttering of the eye happens prior to an angle of 45 degrees and whether or not it also happens at a maximum deviation. The maximum deviation would be the furthest point from the left or the right eye from which that person can see. The sooner this fluttering occurs the theory is the more alcohol you have in your system. It’s not an exact science but they are saying it’s a tool among many tools that are allowed to be used to help determine whether or not a person is operating under the influence.

Interviewer: Do they administer that test while a person is sitting down or standing?

Some Officers Deviate from the Standard Administration of the HGN Test

Steve Tomeo: They are supposed to do it while the person is standing and it’s generally they are supposed to do it outside of the car. However, a number of police officers will violate these standards and do it while the individual is in the car.

You can imagine if they are supposed to do it outside the car while you’re standing and police officer is standing in front of you with the stimulus 12 to 15 inches in front of your face held a little bit above eye level. He’s going in a right-left, right-left back and forth like that, you can imagine what it must be like if a person is sitting in the car has to turn his head towards left looking at the police officer who’s standing above him on the outside while he is in the inside.

It’s hard for me to imagine that if the standardized method is one way, how a reading when the test is given in a non-standardized fashion can be relied upon. Oftentimes, the courts let that into evidence.

Other Lights, Such as Those on the Police Car Can Serve as a Distraction during the Administration of the HGN Test

Interviewer: Do you ever hear clients tell you that the lights of the police officer’s car serve as a distraction?

Steve Tomeo: Absolutely. I would say that in many cases the police officer has their high-intensity lights on top of their cars shining in addition to their headlights, in addition to their overhead red lights blinking on and off. There are all sorts of distractions like that in addition when the test is administered on the side of the road or on a busy thoroughfare.

Any Action You Perform That Deviates from the Standard Is Counted against You

Interviewer: If they see someone swaying would that be something that may count against them?

Steve Tomeo: Everything is negative. They’ll say any one thing is not indicative of operating under the influence or that you’re impaired or under the influence of alcohol and/or drug, but everything combined goes against this. If they are giving the test and you’re standing up and you’re swaying back and forth, they’ll note that in their report and of course it doesn’t help you because in my experience most people think in a negative fashion.

Some people naturally have bad balance. Some people have had traumatic brain injuries. Some people have other medical conditions that caused them to not be as good at balancing. People that are oftentimes over 65 a lot of times have balance issues.