High Eyes: What Different Drugs Do to the Eyes, and What They Do Not Tell You
Red eyes, pinpoint pupils, wide pupils, drooping lids: the eyes give away different drugs in different ways. This guide covers what cannabis, stimulants, opioids, and sedatives do to the eyes, how long it lasts, and why eyes alone are never proof of anything.
Updated First published Leer en español
Published by DetoxNJ.comHow we check facts
Why cannabis turns eyes red
THC lowers blood pressure slightly and widens blood vessels, including the tiny ones on the surface of the eye. More blood in those vessels reads as red or bloodshot. It is the same mechanism that makes THC lower pressure inside the eye, which is why cannabis was studied for glaucoma. Redness usually starts within minutes of smoking or vaping, peaks in the first hour, and fades over two to four hours. Edibles produce it later and for longer. Some people barely redden at all; it varies with dose, strain, and the person.
What cannabis does not do
It does not reliably change pupil size. Some studies find slightly larger pupils, others find none, and the difference is too small to see across a room. Eye drops that constrict surface vessels hide the redness in minutes, which is why the redness test has never been reliable for anyone who cared to hide it. Slower blinking, a glassy look, and drooping lids are more consistent, but they are also what tired looks like.
The eye signs of other drugs
| Drug | What the eyes do | Why |
|---|---|---|
| Cannabis | Red, glassy; heavy lids; pupils roughly normal | Surface blood vessels widen |
| Opioids (heroin, fentanyl, oxycodone) | Pinpoint pupils that do not widen in a dim room; drooping lids, nodding | Opioids constrict the pupil directly; a hallmark of overdose |
| Stimulants (cocaine, meth, Adderall) | Wide pupils, rapid blinking, staring; sometimes twitching | Adrenaline-like effect dilates the pupil |
| Alcohol, benzodiazepines | Drooping lids, slow tracking, eyes that jerk when looking sideways | Sedation and loss of muscle control |
| Psychedelics (LSD, psilocybin, DMT) | Very wide pupils, sensitivity to light | Serotonin effects dilate the pupil |
| Ketamine, PCP | Rapid side-to-side eye movement, blank stare | Dissociative effect on eye control |
The one eye sign that is an emergency. Pinpoint pupils in someone who is very drowsy, breathing slowly, or hard to wake are the classic signs of an opioid overdose. Call 911 and give naloxone (Narcan) if you have it. If they do not wake up, give another dose every 2 to 3 minutes, as the package directs, and stay until help arrives, even if they wake up. Do not wait to be sure.
How long the signs last
Cannabis redness: two to four hours, longer with edibles. Stimulant dilation: several hours with cocaine, much longer with methamphetamine. Opioid constriction: as long as the drug is active, which for heroin or oxycodone is roughly four to six hours and for fentanyl can be shorter but more intense. Alcohol and benzodiazepine eye signs track blood levels. Our guide to what cocaine smells like covers its look, smell, and slang.
How to get rid of high eyes
Time does most of it; cannabis redness clears within the two to four hours described above. Redness-relief drops, the kind with tetrahydrozoline, naphazoline or brimonidine on the label, narrow the surface vessels and hide the redness for a while, and a cool compress may help. Plain lubricating drops (artificial tears) are labeled for dryness, not redness. The tetrahydrozoline and naphazoline labels warn that overuse can make redness worse and that pupils may become enlarged for a while. Nothing sold over the counter returns pupils to normal, so pinpoint or very wide pupils stay until the drug wears off. And if the redness comes from smoke irritation, a contact lens, or an infection rather than THC, drops only cover it. Redness that lasts more than a day, or comes with pain or blurred vision, belongs with a doctor.
How to tell if someone is high by their eyes
One sign means little. A combination, read against the table above, means more. Red, glassy eyes with normal-looking pupils fit cannabis. Pupils that stay pinpoint in a dim room, with drooping lids and nodding, fit an opioid, and if the person is also hard to wake or breathing slowly, that is the overdose picture in the box above and the next step is 911. Wide pupils with staring and fast blinking suggest a stimulant. Every one of those signs also has an ordinary explanation, and the next section lists them.
Why eyes alone prove nothing
Allergies, lack of sleep, contact lenses, crying, swimming, and a screen all night produce red eyes. Anxiety, darkness, and some medications dilate pupils. Migraine medications, eye drops, and some antidepressants constrict them. A parent, a partner, or a supervisor who treats eyes as evidence will be wrong often enough to damage trust and will miss the people who learned to use eye drops years ago. Eyes are a reason to pay attention, not a verdict.
If you are worried about someone
Look at the pattern, not the pupils. Money, sleep, missed obligations, secrecy, new friends, mood swings, and physical changes over weeks tell you far more than one evening’s eyes. Our guide to signs someone needs detox walks through what clinicians actually look for. Our family guide covers supporting someone through detox and early recovery, and our guide to teen detox and treatment in New Jersey covers consent, confidentiality, and PerformCare. For help independent of us, the state’s IME Addictions Access Center at 1-844-276-2777 (24/7) screens NJ FamilyCare and uninsured callers and refers them to treatment, and ReachNJ at 1-844-732-2465 is the state’s general treatment line. Periscope Behavioral Health, our publisher’s admissions line, at (888) 313-3583, can also talk it through with a family member, privately, before anything is decided. What a plan covers depends on the plan and the facility’s network status.
Need help finding detox? Call the admissions line of our publisher, Periscope Behavioral Health: (888) 313-3583. Your call is treated confidentially, and insurance questions are welcome. Free state lines, 24/7: ReachNJ 1-844-732-2465 · NJ IME Addictions Access Center (Medicaid and uninsured) 1-844-276-2777.
Frequently asked
What do your eyes look like when you are high on weed?
Red or bloodshot, often glassy, with heavier lids and slower blinking. Pupils stay roughly normal. The redness comes from THC widening blood vessels on the surface of the eye and usually fades within two to four hours.
How long do eyes stay red after smoking?
Usually two to four hours after smoking or vaping. Edibles cause redness later and it lasts longer. Eye drops that constrict surface vessels hide it within minutes.
What drugs cause pinpoint pupils?
Opioids: heroin, fentanyl, oxycodone, hydrocodone, and methadone. Pinpoint pupils in someone who is very drowsy or breathing slowly are a sign of opioid overdose. Call 911 and use naloxone if available.
What does the term high eyes mean?
Slang for the way the eyes look after using cannabis: red or bloodshot, glassy, with heavy lids and slow blinking. People also use it loosely for the eye signs of other drugs, such as pinpoint pupils from opioids or wide pupils from stimulants.
How do you get rid of high eyes fast?
Only the redness can be cleared fast. Redness-relief drops with tetrahydrozoline, naphazoline or brimonidine narrow the surface blood vessels and hide it for a while, and a cool compress may help; plain artificial tears are made for dryness, not redness. Overusing redness-relief drops can make the redness worse. Left alone, it fades in two to four hours. Pupils are another matter: nothing over the counter returns them to normal, and some redness-relief drops can widen them. Redness that comes with pain or blurred vision, or lasts more than a day, needs a doctor.
What drugs make pupils dilate?
Stimulants such as cocaine, methamphetamine, and Adderall, and psychedelics such as LSD and psilocybin. Anxiety, darkness, and some medications also dilate pupils, so wide pupils alone do not prove drug use.
Request confidential help — 24/7, no obligation.
Prefer to call our publisher's admissions line, Periscope Behavioral Health?
Free state lines, 24/7: ReachNJ 1-844-732-2465 · NJ IME Addictions Access Center (Medicaid and uninsured) 1-844-276-2777
Tell us about your situation and a DetoxNJ care navigator will reach out. DetoxNJ is published by Periscope Behavioral Health, which operates or holds an ownership interest in Emerald Wellness, South Jersey Recovery Program, Palm Beach Recovery Centers, Palm Beach Healing Centers, and Transitions Recovery Program, and is developing a medical detox in Hammonton, NJ (expected Summer 2027). We make an introduction only if you ask us to.