Optometric expert testimony: foundation for the horizontal gaze nystagmus test.

The courts require that a foundation be laid for admission of the Horizontal Gaze Nystagmus Test into evidence. Some courts will not accept peace officers as experts, but will instead require that an optometrist provide the necessary foundation. The optometrist will be expected to establish the correlation between nystagmus and alcohol consumption, and to educate the court on the desirability of the test for use by the law enforcement community. The optometrist should prepare prior to trial to assist the prosecutor in achieving these goals.