Red eyes can have many causes, making it challenging to identify the problem without an eye exam. If your eyes are red, consider what you’ve been exposed to recently. If you’ve used cannabis, that might be the cause.
It’s generally common knowledge that smoking cannabis leads to red eyes. However, cannabis is consumable in many ways, so you may wonder if edibles can make your eyes red.
Do Edibles Make Your Eyes Red?
Yes, edibles can make your eyes red, if they contain THC. It doesn’t matter how THC gets into your body. Whether through a vape, joint, drink, edible, or other smoking apparatus, cannabis will make your eyes red if it has THC (delta-9-tetrahydrocannabinol).
Redness happens because of the effect THC has on your eyes. THC is a cannabinoid that gives you the “high” you feel when you consume cannabis. It also affects your blood vessels, making your eyes red.
Ingesting THC lowers your blood pressure, which dilates your blood vessels. This dilation increases blood flow throughout your body, including your eyes. The blood vessels in the eye enlarge, becoming red for a short period.
Eye redness is temporary, going away with time.
Why Do Your Eyes Get Red When High?
Red eyes are a classic and easily recognized side effect of using cannabis—no matter if you smoke it, vape it, or consume edibles. The main reason your eyes get red when you’re high is due to THC, the active compound in cannabis.
When THC enters your system, it lowers your blood pressure. This causes the blood vessels and capillaries in your eyes to dilate (expand), increasing blood flow to the area. The increased blood flow makes the whites of your eyes (the sclera) appear red or bloodshot. This effect is not caused by smoke or irritation alone; it’s a direct result of THC’s action on your body.
Whether you use sativa, indica, a hybrid, or consume cannabis in edible form, if THC is present, you’re likely to experience red or bloodshot eyes for a period of time after use. The redness is temporary and usually fades as the effects of THC wear off.
If your red eyes are persistent, painful, or if you have concerns about your eye health, be sure to talk to your optometrist, as this could be a sign of a bigger underlying issue.
How Does Cannabis Affect Your Eyes & Eye Health?
Besides red eyes (and maybe the giggles), cannabis lowers eye pressure. Because of this, some people wonder if cannabis can help treat diseases like glaucoma. However, the effects of cannabis aren’t long-lasting—it’s difficult to concentrate or even drive, making cannabis an unideal treatment option.
Research is ongoing into the effect cannabis has on your vision and eye health. Researchers are looking into the possible harm cannabis can have on peripheral vision and visual processing. Currently, there is no definite proof that cannabis can harm your eyes.
If you know you’ve recently had cannabis with THC in any form, that’s the likely cause of your red eyes. In general, eye redness has many potential causes.
Consume Cannabis Responsibly
While there isn’t any confirmed risk for your eye health associated with cannabis, remember to consume this substance safely. Cannabis can affect your decision-making and ability to drive.
The best way to prevent damage from cannabis is to not use it. If you do use cannabis, here are some tips to keep in mind:
- Avoid frequent use of cannabis
- Never use cannabis and drive or operate machinery
- Avoid mixing cannabis with other substances like alcohol
- Consume cannabis in a safe, familiar place
Sativa vs Indica: Do They Make Your Eyes Red?
Many people wonder if certain types of cannabis, like sativa or indica, are more likely to make your eyes red. The truth is, both sativa and indica strains can cause red or bloodshot eyes if they contain THC.
The redness in your eyes is caused by THC’s effect on your blood vessels, not by the specific strain you use. Higher-THC strains (whether sativa or indica) may produce more noticeable redness, while strains with less THC or those that are CBD-dominant are less likely to cause this effect.
So, if you’re using cannabis with THC—regardless of whether it’s sativa, indica, or a hybrid—red eyes can happen. If you want to avoid red eyes, look for products that contain little to no THC.
If you have questions about how cannabis might be affecting your eyes or your vision, book an appointment with Willoughby Doctors of Optometry. Our optometrists can provide advice tailored to your needs, and also check for any underlying health concerns that may be causing your eyes to be red.
Why Else Might Your Eyes Be Red?
While cannabis can make your eyes red, there are many other possibilities. Red eyes can have many causes, some serious and others not. In general, recurring red eyes mean you should visit your eye doctor.
Possible causes of red eyes include pink eye, dry eyes, injury, or blepharitis.
Pink Eye
Pink eye, also known as conjunctivitis, occurs when bacteria, allergens, or a virus causes inflammation in the conjunctiva, the membrane lining your eyelid and eyeball. When this happens, your eye becomes swollen, red, and uncomfortable. This condition can be extremely contagious, depending on the type of pink eye.
The types of pink eye include:
- Bacterial pink eye: caused by bacteria entering the eye
- Viral pink eye: caused by a virus like the common cold
- Allergic conjunctivitis: caused by allergens entering the eye
Dry Eyes
Dry eyes occur when your tears can’t hydrate your eyes effectively. This condition happens due to issues in the tear film. The tear film’s layers (mucus, water, and oil) work together to keep your eyes moist and clean, but problems can arise, leading to fewer tears or poor-quality tears.
Dry eyes can cause redness, irritation, blurry vision, or a burning sensation.
Injury
An eye injury can lead to redness caused by irritation or bleeding. You may get hit in the eye, exposed to an irritant, or experience a foreign object in the eye.
Blepharitis
Blepharitis is the inflammation of the eyelids, typically caused by the meibomian glands surrounding the eyelids becoming clogged or blocked. It’s a chronic condition that can lead to dry, red, irritated eyes.
Key Takeaways
- THC is the main reason cannabis makes your eyes red. The effect is the same, whether you smoke, vape, or eat edibles, THC expands the blood vessels in your eyes causing redness.
- Both sativa and indica strains can cause red eyes. The redness is linked to THC content, not the specific strain or how you consume it.
- Edibles can make your eyes red, too. It’s not just smoking. Any form of THC can lead to bloodshot eyes.
- Red eyes from cannabis are usually temporary and harmless. However, if your eye redness is persistent, painful, or comes with other symptoms, it may be a sign of an underlying health issue. If this is the case, be sure to visit your optometrist.
- Willoughby Doctors of Optometry in Langley, BC can help. If you’re concerned about uncharacteristic red eyes or changes in your vision, our team is here to answer your questions and provide expert eye care.
Red Eyes? Visit Your Eye Doctor
Red eyes are a common reaction to ingesting cannabis, but they can mean many potential eye problems. Make sure you visit your eye doctor if eye redness won’t go away, reoccurs, or your red eyes happen alongside other symptoms.
Contact Willoughby Doctors of Optometry if you’re experiencing red eyes.
