Full formMedical & Health
HGNstands forHorizontal Gaze Nystagmus
Full Form of HGN
What is HGN?
Horizontal Gaze Nystagmus (HGN) is an involuntary jerking or bouncing of the eyeball that occurs when the eyes are moved to the side. In medical terms, nystagmus refers to rapid, uncontrolled eye movements. The HGN test is a standard field sobriety test used by traffic police in India to detect alcohol or drug impairment in drivers. When a person consumes alcohol, the ability to track a moving object smoothly is compromised, causing characteristic jerky eye movements that law enforcement officers can observe. The test involves asking the subject to follow a pen or flashlight with their eyes while the officer notes the angle at which nystagmus becomes evident. In India, the HGN test is often part of the larger Standardized Field Sobriety Test (SFST) administered during traffic checks, especially at night. It is also referred to in forensic science and judicial proceedings related to drunk driving cases. For competitive exams like UPSC, SSC, or state police recruitment, understanding HGN is relevant for questions on forensic evidence, traffic regulations, and criminal procedure. The test is not diagnostic on its own but serves as a strong indicator that further chemical testing (breathalyzer or blood test) is warranted.
HGN का फुल फॉर्म
क्षैतिज दृष्टि निस्टागमस
Example
The traffic constable recorded the driver's HGN response and noted that nystagmus occurred at 45 degrees, suggesting a high probability of intoxication.
HGN — frequently asked questions
What is the full form of HGN?
HGN stands for Horizontal Gaze Nystagmus, an involuntary jerking of the eyeball that is used as a field sobriety test to detect alcohol impairment.
How is the HGN test conducted by Indian traffic police?
The officer holds a pen or light 12-15 inches from the driver's face and moves it horizontally. The driver must follow with their eyes while the officer observes for jerky movements that indicate intoxication.
Is the HGN test admissible as evidence in Indian courts?
Yes, but it is typically considered corroborative evidence. Courts often require expert testimony from a forensic expert or police officer trained in SFST administration.