Flashing a Light in Someone's Eye During an HGN Test: Understanding the Procedure and its Implications
The horizontal gaze nystagmus (HGN) test is a standardized field sobriety test (SFST) used by law enforcement to assess potential impairment due to alcohol or drug use. A crucial part of this test involves observing the eye's involuntary jerking movements (nystagmus) as the subject follows a moving stimulus—often a penlight. However, the method of using the light and its impact are often misunderstood. This article will clarify the procedure and address common concerns surrounding flashing the light.
What is the HGN Test and Why is a Light Used?
The HGN test assesses three key clues indicative of impairment:
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Lack of Smooth Pursuit: As the subject follows the moving stimulus (the penlight), their eyes should smoothly track it. Jerky movements or "jerks" suggest impairment.
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Distinct Nystagmus at Maximum Deviation: When the subject's eyes are turned as far as possible to the side, involuntary jerking (nystagmus) becomes more pronounced. This is because the nerves controlling eye movement are stretched to their limit, making impairment more apparent.
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Onset of Nystagmus Prior to 45 Degrees: Nystagmus that begins before the eyes reach a 45-degree angle of deviation also suggests impairment.
The penlight serves as a consistent and easily controlled stimulus. Its movement allows the officer to observe the subject's eye movements closely. It's crucial to note that flashing the light is not a standard part of the HGN test. The light is moved smoothly and steadily. Any suggestion otherwise is a misrepresentation of the procedure.
What happens if the officer flashes the light?
Flashing the light is not a prescribed part of the HGN test and could be considered improper procedure. While a momentary flash might not significantly alter the results in a trained officer's observation, it could introduce inconsistencies and potentially invalidate the test if reported appropriately. A good officer will maintain a steady, smooth movement to ensure accurate observation and test validity.
Is flashing a light in the eye during the HGN test illegal?
Flashing a light directly into someone's eyes isn't illegal in the context of an HGN test per se, but it is against established testing protocols and best practices. The legality stems from whether the officer's actions constitute excessive force or an improper conduct of the test. If the flashing is deliberate, aggressive, or causes undue distress, it could be grounds for legal challenge. Furthermore, if the officer's actions lead to a misinterpretation of the test results, it could impact the admissibility of evidence in court.
What should I do if an officer flashes the light during the HGN test?
Document everything. If possible, record the interaction (if this is legal in your jurisdiction). Note the time, date, location, the officer's badge number, and details about the light flashing. This documentation will be critical if you choose to challenge the test results. Consult with a legal professional to discuss your options.
Can flashing a light affect the accuracy of the HGN test?
While a single flash might have minimal impact on the overall test result for a trained officer, repeated or aggressive flashing could create artifacts that obscure the officer's ability to accurately assess nystagmus. This might lead to an inaccurate assessment of impairment.
What are the potential legal consequences of a flawed HGN test?
A flawed HGN test, due to improper procedure such as flashing the light, could lead to the exclusion of test results as evidence in court. This could significantly impact the outcome of a DUI or DWI charge.
In conclusion, while the HGN test involves using a penlight, the light should be moved smoothly, not flashed. Flashing the light is not standard procedure and could compromise the test's validity. If you believe an officer conducted the HGN test improperly, document the event thoroughly and seek legal counsel.
