If you have been asked to complete field sobriety tests in the past, then you may be aware of the horizontal gaze nystagmus, or HGN, test looks to see if your eyes are moving from side to side smoothly.
A nystagmus occurs when there is involuntary jerking of the eyes. Normally, this occurs when someone has a neurological disorder, is impaired by certain drugs or has been drinking alcohol. Typically, as someone becomes more impaired by drugs or alcohol, the HGN increases in severity.
The problem with the horizontal gaze nystagmus test
The biggest issue with the horizontal gaze nystagmus test is that it’s possible to have nystagmus when you are completely sober. Someone with neurological issues or seizure activity could have nystagmus occur without having anything to drink.
Generally speaking, it’s possible to exclude the chances of a medical condition or injury causing nystagmus if the testing officer looks for differences in the sizes of the pupils, checks for a resting nystagmus or sees that equal tracking is or is not present. However, the test is still subjective, so there is a risk that you could be accused of being impaired when you are not.
How can you challenge the HGN test?
It’s possible to challenge the test and have it excluded from evidence in some cases. Did you know that this test is only around 77% accurate when performed correctly? Additionally, there are medical conditions, including eye issues and other medical problems, which could lead to nystagmus.
If you have a medical history of nystagmus, this could be used to disprove the officer’s findings. Depending on the severity of nystagmus and how the test was performed, you may also be able to argue that the test should not be admissible for other reasons.
You deserve an opportunity to defend yourself
If you’re accused of drunk driving, you deserve the opportunity to defend yourself. With the right defense, you may be able to get the case against you dropped or to have the charges altered to something less serious. Every case is unique, so it’s important to know what your legal rights are and to protect your own best interests.