HORIZONTAL GAZE AND NYSTAGMUS: This is the FST that is most common. The officer will ask a person to stand in certain position and follow the pen or the light with their eyes. The officer is trying to gage the amount of involuntary bounce that is in your pupils. The state's argument is the more bounce, the more intoxicated the person is at the time of testing. [ return to top of glossary

Horizontal Gaze Nystagmus. Gaze nystagmus that occurs when the eyes gaze or move to the side along a horizontal plane.

Horizontal Gaze Nystagmus. A field Sobriety Test that Massachusetts Courts have declared to be non-scientific, and can't be used as evidence that you were impaired in Massachusetts Courts.