Determining if someone is intoxicated is not always straightforward. While there are some clear signs like slurred speech and lack of coordination, other signs can be more subtle. One potential indicator is changes in a person’s eyes and eye movements when they are under the influence of alcohol or drugs. In this article, we’ll explore the question: can you tell if someone is drunk by looking at their eyes?
How alcohol affects the eyes and vision
Alcohol is a depressant that affects the central nervous system. It inhibits neural activity in the brain which leads to the intoxicating effects associated with drinking. Alcohol impacts the visual system in a few key ways:
- It causes pupils to become dilated or enlarged.
- It disrupts the ability to focus and converge eyes properly.
- It impairs the ability to track moving objects accurately.
- It decreases inhibition which can lead to nystagmus (involuntary eye movements).
These effects on vision and eye coordination can become noticeable even when someone has only had 1-2 drinks. As alcohol consumption increases, the impairment and disruption to normal eye functioning and control also increases.
Clues to look for in someone’s eyes when drunk
Here are some specific signs in the eyes to look for that may indicate someone is intoxicated:
- Pupil size – Alcohol typically causes pupils to dilate or enlarge. Pupils that appear larger than normal or do not respond to light properly could indicate intoxication.
- Nystagmus – This refers to uncontrolled, repetitive eye movements that cause the eyes to jerk or bounce around. Alcohol is one of the most common causes of nystagmus.
- Eyelid tremors – Alcohol can cause the eyelids to flutter or tremor, especially when trying to maintain gaze in one direction.
- Red or bloodshot eyes – While red eyes have other causes, bloodshot eyes in combination with other signs could substantiate drunkenness.
- Lack of convergence – This refers to the inability for the eyes to turn inward and properly focus on a close object. Many intoxicated people will have difficulty crossing their eyes.
- Poor tracking – This sign looks at the ability to smoothly track a moving object with the eyes. Impaired tracking could indicate that someone has been drinking.
Other potential eye-related signs of intoxication
In addition to the specific eye signs above, there are other eye-related red flags that could suggest someone is under the influence. These include:
- Glassy, unfocused eyes with a dazed expression.
- Delayed reactions to visual stimuli (slow response when something moves in front of face).
- Eyelids drooping or appearing heavy.
- Inability to maintain eye contact/gaze consistently.
- Difficulty keeping eyes fully open, repeated blinking or slow eyelid reactions.
Factors that influence visible eye changes when drunk
Several factors impact how clearly the effects of alcohol may show in someone’s eyes and gaze. These include:
- Amount of alcohol consumed – The more drinks someone has, the more likely eye issues will be noticeable.
- Tolerance level – People develop tolerance over time. Experienced drinkers may not show obvious signs at lower intoxication levels.
- Genetic differences in responses – Some people are just biologically prone to more visible effects in eyes than others when drinking.
- Rate of drinking – Quickly drinking a large amount often exacerbates the appearance of eye changes compared to pacing over time.
- Fatigue level – Fatigue and alcohol have additive effects on eyes. Being tired makes eye issues more pronounced.
- Other drugs – Many drugs also affect the eyes. Combining other substances with alcohol makes signs more apparent.
Can you determine specific BAC level from eyes?
While visible eye changes can indicate that someone has been drinking and is intoxicated, it is not possible to determine someone’s precise blood alcohol concentration (BAC) level just from looking at their eyes. BAC is determined by specialized breath, blood, or urine tests.
However, police officers trained to recognize and assess intoxication levels will look at the eyes during field sobriety tests. They use eye examinations along with other cognitive and coordination tests to determine if a driver may be over the legal intoxication limit and require more formal BAC testing.
Conclusion on determining drunkenness from eyes
In summary, the eyes can display visible effects and impairments when someone is intoxicated from alcohol. Signs like enlarged pupils, nystagmus, poor tracking, and lack of convergence are good indicators that further sobriety assessment or BAC testing may be warranted. However, eye signs alone cannot definitively determine BAC levels or specific degrees of intoxication. Police and medical personnel will combine structured eye exams with other physical tests, observations of behavior and demeanor, and formal BAC testing if required, to ascertain if someone is legally drunk based on their jurisdiction’s limits.
For the average person, looking for multiple eye-related red flags in combination with other unusual behaviors can provide reasonable suspicion that someone may have had too much to drink. But only trained professionals can rely on eye assessments as part of standardized field sobriety or medical intoxication screening techniques. On their own, observations of eye changes only indicate possibility, not proof, of drunkenness at specific thresholds.
Related questions
What physical signs or behaviors most clearly indicate someone is drunk?
Some of the most definitive signs someone is drunk include:
- Slurred, slow, or confused speech.
- Lack of coordination, stumbling, difficulty walking straight.
- Delayed responses and reflexes.
- Poor or dangerous judgment, impulsive actions.
- Dramatic mood changes, exaggerated emotions.
- Memory problems, blackouts.
- Vomiting, nausea.
- Disorientation, confusion.
Why do people’s eyes look different when they are drunk?
Alcohol acts as a depressant on the brain and central nervous system. It inhibits neural activity in areas that control eye muscles and eye movements. This leads to reduced coordination of the small muscles around the eye and impaired control of eye positioning and tracking. Some specific effects that cause the eyes to appear different when drunk are:
- Pupil dilation due to alcohol inhibiting the pupillary light reflex.
- Inability of the eyes to converge on near objects or track moving objects accurately.
- Nystagmus, or repetitive involuntary eye movements that the brain cannot control.
- Eyelid tremors caused by alcohol enhancing neurotransmitter effects.
- Fatigue-like effects of alcohol depressing ocular motor control.
Are there any other causes for the eye signs associated with being drunk?
While alcohol is one of the most common causes of eye changes like nystagmus, pupillary dilation, and fatigue-like gaze, there are other potential causes including:
- Use of other drugs, both illegal and prescription medications.
- Traumatic brain injuries.
- Neurological disorders such as stroke, multiple sclerosis, or neuropathy.
- Inner ear problems causing vertigo.
- Extreme fatigue, sleep deprivation.
- Head injuries or concussions.
- Eye diseases like glaucoma or retinal damage.
So while seeing eye issues may raise suspicion of alcohol intoxication, a medical evaluation could be warranted to rule out other potential explanations.
Can wearing contact lenses make the eye effects of alcohol worse?
Contact lenses do not necessarily make the eye-related effects of alcohol worse or more severe. However, contact lenses could potentially exacerbate some symptoms or increase risks in the following ways:
- Contacts may feel uncomfortable, irritating, or dry when worn by a drunk person due to lack of tear production and decreased blink response.
- Having contacts in increases risks of eye infection or corneal abrasion if someone passes out drunk while still wearing their lenses.
- Contacts could potentially dislodge or be damaged during periods of nystagmus, impaired motor control, or vomiting while intoxicated.
- A very drunk person may accidentally touch and contaminate contacts with unwashed hands.
So while contacts do not actually worsen the eye effects of alcohol consumption, they may amplify associated discomforts and risks to some degree. Anyone wearing contacts should remove them before drinking large amounts of alcohol or if they start experiencing impaired motor control or nausea when drinking.
Key takeaways
- Alcohol causes noticeable effects on the eyes due to its depressive effects on neural control centers.
- Signs like nystagmus, pupil dilation/changes, and fatigue-like staring can indicate intoxication.
- Eye assessments alone cannot definitively prove drunkenness or determine BAC levels.
- Contacts may increase subjective discomfort when drunk but do not worsen eye effects directly.
- Other drugs and medical conditions can also cause eye changes resembling alcohol intoxication.