When discussing the effects of opioid use on the human body, most people think about addiction, long-term health consequences, or the dangerous impact of an opioid overdose. But there are also many short-term symptoms of opioid consumption that doctors, parents, and educators should be aware of—including changes to a person’s vision and eye health.
So, do opioids dilate pupils? Do all opioids affect the size of a person’s pupils? How can you determine if someone is taking opioids based on the appearance of their eyes? In our guide, we will explain the connection between opioids and pupil dilation and give you a few tips to figure out whether you or someone you care about needs help with opioid addiction.
Effect of Opioids on Pupils
Opioids are known to affect the size of a person’s pupils—you may notice someone’s pupils have become smaller than usual after they have taken opioids. Constricted pupils—also called miosis—are a typical symptom of short-term opioid use. In many cases, opioid consumption leads to pupil constriction instead of pupil dilation. Note that in case you observe unusually small pupils together with symptoms such as shallow breathing and loss of consciousness, you should seek medical help for the person in question—they may be going through an opioid overdose.
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Why Do Opioids Affect Pupil Size
The drug class in question impacts the part of the brain that is responsible for automatic body functions—this includes the body’s response to bright or low light. Normally, the human body adapts to surrounding light levels without a person having to think about it; however, opioid use may interfere with this function, making it challenging to be exposed to sunlight or remain in a poorly lit room. Opioids stimulate the parasympathetic nervous system of the individual, leading to the contraction of the iris sphincter muscle and subsequent constriction of the pupils.
How Long Do Pupil Changes Last
There is no fixed duration for pupil constriction after opioid consumption—on average, you may expect the pupils to remain smaller for 4-6 hours after the drugs are ingested. The size of the pupils should return to normal after the effect of the opioids wears off. Keep in mind that constant drug use—opioids and other drug categories—may hurt a person’s eye health and vision. If you are concerned about persistent pupil dilation or constriction, as well as symptoms such as eye pain, dizziness, and blurred vision, consult a healthcare provider.
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Recognizing Opioid Use by Pupil Size
Can you tell if a person is taking opioids by simply looking at their eyes? While pinpointing drug use based on a single symptom is not possible, changes in pupil size should alert you, especially if they are accompanied by strange behavior, drowsiness, and nausea. If you are unable to find an explanation for the sudden constriction or dilation of the person’s pupils, talk to them about the possibility of drug abuse, let them know you are concerned about their well-being, and encourage them to visit a doctor.
Other Drugs That Cause Pupil Dilation
Besides opioids, other drugs may lead to pupil dilation:
Cannabis. Also known as marijuana, this drug is famous for its psychoactive properties—it may accelerate the heart rate of the user and increase their sensitivity to light, accompanied by pupil dilation.
Cocaine. If a person’s pupils have become enlarged, they are anxious, confused, and energetic, and their nose is runny, they may be abusing cocaine.
LSD. Hallucinogenic drugs such as LSD are known to affect a person’s perception and behavior as well as temporarily increase the size of their pupils.
FAQs
Do all opioids cause pupil constriction?
Yes, the majority of drugs from the opioid category will make the user’s pupils smaller for a limited time—this is considered a normal reaction to opioid consumption.
What drugs other than opioids make pupils smaller?
In addition to opioids, drugs such as heroin, morphine, and fentanyl are known to cause pupil constriction.
What are the symptoms of opioid use?
Opioid abuse may lead to a large number of symptoms: euphoria or extreme agitation, confusion, slow movement, and poor coordination. Nausea, vomiting, and low blood pressure are some of the signs to look out for.
What are the dangers of opioid addiction?
Addiction to opioids may lead to adverse consequences for a person’s life, both physical and psychological.
How to treat opioid addiction?
If you believe you or someone you care about is struggling with opioid addiction, reach out to a healthcare provider.
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Reach Out to Touchstone Recovery Center
We hope that our guide was helpful—while pupil dilation is not always caused by opioids, this drug category is often behind changes in the person’s eye.
For personalized assistance, do not hesitate to get in touch with Touchstone Recovery Center—our trained professionals will be there for you and your loved ones to provide you with all the resources you need to start the recovery journey.
