Cannabis And Red Eyes: What Is The Relationship?

If you are a cannabis user, chances are that at some point you have looked in the mirror and wondered, “Why are my eyes so red?” Although every user’s experience with cannabis is unique, red eyes are usually the most obvious sign of cannabis ingestion. Some people experience it each and every time they use cannabis, while others only find it occurring occasionally. Join us as we delve into why cannabis makes your eyes red and whether there is any reason to be concerned about it.

Why Do My Eyes Get Red After Consuming Cannabis?

Cannabis makes your eyes red due to the interaction between THC and your blood vessels. When you consume THC, the main psychoactive compound in cannabis, it enters your bloodstream and interacts with your endocannabinoid system (ECS). The ECS contains receptors that are spread all throughout your body, namely CB1 and CB2 receptors.

When you get red eyes from consuming cannabis, it is due to the THC molecules binding to the CB1 receptors found in the brain and eyes. This binding stimulates vasodilation in your eyes’ blood vessels, increasing blood flow and decreasing blood pressure. As your blood pressure lowers, your blood vessels start to dilate. This effect actually occurs all over the body, but it is most obviously visible in your eyes’ capillaries.

Smoking cannabis can decrease intraocular pressure by up to 30%, making it useful for treating eye conditions, such as glaucoma. These impact the optic nerve and can eventually lead to partial or complete blindness. Glaucoma is mostly caused by high intraocular pressure (IOP). So while this increased blood flow to the ocular capillaries is what causes your eyes to go red, it also provides relief for medical cannabis users who suffer from glaucoma.

Does The Consumption Method Matter?

There are many different cannabis consumption methods, including dabbing, tinctures, vaping, smoking, and edibles. If you are a seasoned user, you might have noticed that your eyes turn red no matter what consumption method you use. This is because the red eye effect caused by cannabis is directly related to its THC concentration. 

When THC enters your bloodstream, some will bind to CB1 receptors in the eye, regardless of the consumption method. Strains with a higher THC concentration are also more likely to have a more potent effect on your eyes. 

The only difference between methods of cannabis consumption is the amount of time it takes to show. Vaping and smoking quickly results in red eyes as the THC moves directly into your bloodstream. Oral consumption often has a slower onset of red eyes since the THC needs to pass through your liver before it can enter your bloodstream.

When Will The Redness Go Away?

Red eyes due to cannabis consumption will usually go away within one or two hours of noticing the effects. However, this also depends on how quickly your body can metabolise THC and the overall THC concentration in your products. Some people do not notice any changes at all, while the others have reported having red eyes up to three hours after first noticing changes.

Do Other Cannabinoids Make Your Eyes Red?

The potential of cannabis to cause red eyes is tied directly to the fact that it contains THC. THC causes an increase in blood pressure and heart rate, leading to the expansion of your ocular vessels. Therefore, the more THC you consume, the redder your eyes will become.

However, there are some terpenes, the compounds that are responsible for the taste and smell of cannabis, that may irritate the eyes. If you are looking to avoid red eyes, it is a good idea to stay away from strains that are high in pinene, terpineol, limonene, carene, and butanol.

Why Doesn’t Everyone Experience Red Eyes When Using Cannabis?

If you or someone you know has never had the issue of dealing with red eyes from cannabis, it could all come down to genetics, luck, or consumption styles. Those who have built up a cannabis tolerance are also much less likely to experience red eyes. If your blood pressure is already high, you will most likely not notice any changes. 

How Can I Get Rid Of Red Eyes From Cannabis?

Although red eyes are a completely normal and harmless side effect of consuming cannabis, many users view it as an unwanted issue. Luckily, there are a few ways to take care of red eyes caused by cannabis consumption, including:

• Eye drops
• Caffeine
• Cold compress

Eye Drops

Over the counter eye drops that are marketed for allergy treatment are one of the most common methods used to reduce the appearance of red eyes caused by cannabis. Since these eye drops are used to treat allergies, they contain tetryzoline. This is a vasoconstrictor, which reduces blood flow and minimises the appearance of redness in the eyes.

Caffeine

Caffeine is similar to eye drops in the sense that it also stimulates vasoconstriction. It reduces blood flow to the eyes and decreases redness. Consuming coffee, tea, energy drinks, and sodas can help you to get your eyes back to normal.

Cold Compress

Coolness causes blood vessels in the peripheral body parts (like your ears and eyes) to constrict as blood flow is reduced to these areas. This is a very old survival tactic our bodies undergo naturally when we are cold so that most of our blood keeps going to our most vital organs (the heart and brain). 

You can try to place a cold compress over your eyes, or splash your face with some cool water, to reduce the redness. 

Cannabis consumption has the potential to leave users with red eyes, and although this is no cause for concern, many users would prefer to get rid of this side effect as soon as possible. Remember that red eyes are directly linked to the THC content of your product, so the more THC in your product, the redder you can expect your eyes to get. If you are struggling with red eyes, it is worth it to try eye drops, caffeine, and or a cold compress. Otherwise, just wait one to two hours for it to fade away naturally.