One of the most sure-fire signs that someone is high on cannabis is red eyes. This is usually blamed on irritation from smoke, but this is a common misconception. Marijuana makes the eyes red for the same reason it is used to treat glaucoma; this is a physiological mechanism known as vasodilation.
How Smoking Weed Can Cause Red Eyes?
The vasodilation that causes the red eyes is triggered by the main psychoactive cannabinoid THC, which is only of the active components of cannabis. Cannabinoids interact with the cannabinoid receptors in the body, particularly in the eyes. Once THC binds to cannabinoid receptors, blood pressure is lowered, which causes the dilation of blood vessels and capillaries. In the eyes, the ocular capillaries dilate that causes blood flow to the area and creating the red appearance of the sclera.
Do cannabis edibles also cause red eyes? Edibles, like tinctures and topicals, also contain THC, so they can also cause the sclera to turn red because of vasodilation. For people with glaucoma, the THC-induced vasodilation of the ocular capillaries temporarily reduces intraocular pressure. This is the main symptom of glaucoma that can lead to optic nerve damage and vision loss. Thus, reducing this pressure is crucial in treating the disease. one study showed that smoking cannabis reduced intraocular pressure by 30 percent.
Smoking Weed Does Always Cause Red Eyes?
Although red eyes are a giveaway that a person is smoking cannabis, it is not always a guaranteed symptom. Every cannabis strain has a different concentration of THC. Thus, someone may experience very red eyes after consuming a high THC strain, but barely have it after a low THC strain. There is still more at play than just THC content, though, as there are cannabis strains that have different effects on different users. These effects vary depending on a few factors, including genetics, gender and overall health.
Whether a person experiences red eyes or not is mainly influenced by blood pressure. For example, those with high blood pressure require more THC to lower their blood pressure to cause bloodshot eyes. Meanwhile, those with naturally low blood pressure can easily manifest this symptom. That said, people with cannabis allergy or those who smoke can experienced exacerbated symptoms. But for users with an allergy, red eyes are usually the least of their concerns.
How to Treat Red Eyes after Smoking Weed
Red eyes is a harmless side effect of consuming cannabis and should not be a problem. It can be a nuisance, however, especially those who need to medicate with marijuana throughout the day. Because of the stigma surrounding its use, attending school or work with red eyes can trigger unwanted attention and even legal questioning. The good news is that there are a few strategies you can implement to reduce its severity after using weed.
- Treat with eye drops. Over the counter eye drops that are designed to treat redness, itching and allergies are the most effective way to alleviate red eyes. These drops reduce blood flow to the eyes and its accompanying redness.
- Home remedies. You are bound to have items in your house that can trigger vasoconstriction. Eating dark chocolate, drinking coffee, placing an ice pack over your eyes or splashing water on your face can help alleviate red eyes.
- Wait for the symptoms to subside. The redness with eventually subside, so you can be patient and simply wait until the THC passes through your system. You will have wait anywhere between 2 and 12 hours, depending on a few factors, including THC dose and administration route.
To prevent red eyes after smoking cannabis, opt for a low THC strain or CBD strain. Opting for a strain with little or no THC content will minimize the unwanted side effect, although it might cause you to not experience the same psychoactive effects. Another way to prevent it is to plan and manage your time. If you need to use weed before an important event, do so in advance so your eyes will have time to recover.