One of the most common questions people ask when they start smoking is,”why marijuana makes your eyes red?” Bloodshot eyes are by far the most noticeable sign that a person’s high. And the image of a red-eyed marijuana user has become a mainstay in pop culture.
What is the reason for bloodshot eyes?
Most people assume that their red eyes are a result of the smoke itself drying out their eyes. And while this might add to the redness—especially if you’re in the middle of a super smoky hotbox sesh—it’s not the real reason.
In fact, your eyes will probably get just as bloodshot if you take edibles, if you vape, or anything else.
It doesn’t matter how the cannabis gets into your body. That’s because it’s the THC that makes your eyes turn red.
THC is the primary psychoactive ingredient in cannabis. It’s what gives you the sensation of being high.
But it also interacts with your body in other ways as well. One effect of THC is decreased blood pressure.
When your body’s blood pressure drops, your blood vessels and capillaries get larger in an attempt to make up for the lower pressure and maintain a good blood flow.
This happens especially in your eyes. When the THC makes your blood pressure drop, the blood vessels in your eyes dilate.
These expanded blood vessels allow blood to circulate throughout your eyes more freely, which makes them look red and bloodshot.
The fascinating thing is that this same phenomenon is precisely what makes marijuana such a good treatment for glaucoma.
When a person has glaucoma, they experience a lot of built up pressure in their eyes that can eventually lead to decreased eyesight. But when blood vessels in the eyes dilate, the improved blood flow helps relieve that pressure.
Studies have found that THC can help reduce intraocular pressure by as much as 25%. For people with glaucoma, that can make a huge difference.
How do I get rid of my red eyes?
Since the redness that comes from marijuana is the result of things going on inside your body, there aren’t a lot of effective ways to get rid of the redness.
The next time you’re freaking out about why marijuana makes your eyes red, grab some eye drops or eat some foods with caffeine, chocolate or salt.