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You’re headed to your friend’s place to hang out. It’s been a while since you’ve seen them and you’re excited about having dinner and watching a movie. You wonder what they’ve been up to recently – they’ve been busier than usual. Or at least, that’s what you assume, based on the fact that they haven’t shown up for your friends’ usual game night in a while. You just hope they’re doing okay.
You walk up to their front door and knock lightly on the wood before shooting them a text letting them know you’re here. After a moment you hear scuffles behind the door before it swings open. You greet them but then you immediately notice something seems different. Something about their appearance isn’t quite normal – wait, their eyes seem… different?
What you don’t know is that there are drugs that cause dilated pupils, and your friend has been taking them recently. It’s why they’ve not been showing up for card game nights and why they seem “busier” than normal. Why does this happen? Is it dangerous? Are dilated pupils a sign of something else dangerous?
These stories are not uncommon here in Oregon. In fact, Oregon had the highest percentage of people aged 12+ across the United States who participated in illicit substance use in 2021. As the oldest non-profit rehab center in the state, our team here at Serenity Lane knows a thing or two about substance use and its side effects. Not all of them are as well-known, making them easy to overlook. We want to educate people about substance use so they can better recognize the signs and side effects when they see them. Today we’re going to look at drugs that cause dilated pupils, what this means, and what you can do about it.
Your pupil is the black dot in the center of your eye. It’s used to bring light into your eye so you can see the world around you. When this black dot grows in size, that’s known as dilation. This can occur for a number of reasons, the most common being when a person is standing in darkness. The pupils dilate in order to take in more light. When you’re in light, they shrink down so they can take in less light.
The exact size of a pupil depends on the amount of light in your environment. It’s normal, for example, for a pupil to be small when you’re outside on a sunny day. It’s also normal for your pupils to be large if you’re in a dark movie theater. Have you ever noticed that you can’t see right away when you step into a dark room? Or if you emerge from a dark room into the light it can hurt or you feel blinded for a moment? This is due to your pupil needing time to adjust to the new light level around you.
There are exceptions for pupil size, however. For example, pupils have been known to dilate more when a person is feeling aroused. Additionally, dilated pupils are a common sign of head trauma. If you’re in a dark room and your pupils stay super small, or if you’re outside in bright light and your pupils stay large, something could be wrong.
Different substances have dilated pupils as a potential side effect. Some can have it from use itself, while others can occur due to withdrawal. Let’s take a look at some of the most common substances that can cause dilated pupils.
There are a variety of reasons why different substances can cause your pupils to dilate. The exact reaction can depend on the substance you’re taking.
For some substances, like ones that are known to cause hallucinations and impact other behavioral changes, your pupils can dilate due to adrenaline or different stimuli you’re experiencing while on the substance. In other cases, muscles relaxing or increased feelings of sexual arousal can cause pupils to dilate.
Some substances can cause the opposite as well, commonly referred to as pinpoint pupils. This is very common during opioid overdoses, such as heroin, and can happen due to the chemicals in your body combined with muscle contractions.
While we already covered the most basic reason earlier with light levels, pupils can also dilate for other reasons that are entirely natural. The primary cause for dilated pupils besides light is adrenaline, especially the fight or flight response. This rush can make your pupils dilate in order to take in more information. Some compare it to how a cat’s pupils dilate when they’re playful or stalking their prey.
While the act of dilation itself is not dangerous, as this is done even during natural occurrences, the strain or excess light that can occur during dilation can impact your eyesight. If you’ve ever had your eyes dilated at an eye doctor, they tell you to not look at the sun or bright screens for a bit due to your pupils being wide open. With your eyes letting in more light than it needs, you could have the potential to damage your vision.
Rarely is pupil dilation permanent. Even in the case of head injuries where they’re forced to stay dilated due to pressure in the brain, this too will eventually go away with proper healing and treatment.
Law enforcement often looks for several indicators if they believe someone might be intoxicated, and pupil dilation can be one of those signs. If your pupils are dilated and you’re not showing any other signs of intoxication, however, they will likely not assume your dilation is from drugs.
If you’re noticing signs of substance use in yourself or a loved one, such as dilated pupils often happening when they shouldn’t, help is out there. Pupil dilation doesn’t have to be permanent, and with proper treatment, you can help your vision be healthier.
Part of substance use treatment is addressing the side effects, especially ones that can be ongoing after substance use has stopped without proper treatment. Recovery should be well-rounded, if it only addresses one aspect it doesn’t make for a strong foundation for long-term recovery.
Our master’s level team has years of experience in the world of recovery, and we’re here and ready to help. Serenity Lane has locations throughout the state of Oregon too, so you can find a facility that isn’t too far from home. With the full continuum of care available for you, we’ll support you along your whole recovery journey.
If you have any questions about our programs, treatment plans, or anything else, don’t hesitate to give us a call at (800) 543-9905. Our Serenity Lane team wants to support our whole community and lower the stigma surrounding substance use. We’re ready to begin whenever you are.
What medications cause dilated pupils?
Commonly medications like Sudafed and antihistamines can have the side effect of dilated pupils. Different eye drops can also impact pupil dilation, too.
When should I be concerned about dilated pupils?
If you notice your pupils aren’t properly dilating with light changes, or if your pupils are different sizes, you should reach out to your doctor. This could be due to head trauma and it’s important to get that checked out.
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