Many people come into my office and tell me about their field sobriety tests.  Often they say, "I know I passed the eye test, I did everything I was supposed to do on that test."  A person may have followed all of the instructions, but that is not the main purpose of the test.  The officer is looking for something that people don’t even know they have.   This is called Horizontal Gaze Nystagmus (HGN).  It is a central nervous system disorder that can be caused by alcohol or other central nervous system depressants.  Some points to remember about HGN:

• HGN is an involuntary twitching of your eyeballs.
• You do not know that your eyeballs are twitching and it does not cause your vision to be hindered.
• You cannot practice this field sobriety test because it is involuntary movements of the eyeball.
• HGN will only indicate to an officer that there is alcohol in your system, it will not tell an officer the level of your blood/breath alcohol