Why Can Weed Cause Red Eye? [Here’s the Science]

Wouldn’t it be nice to finish a bong load or a relaxing doobie without the world knowing that you’re stoned? For some cannabis users, it is possible to hide their high, but in a significant number of people, red eyes are a nightmare because this symptom is a tell-tale sign that they’ve been indulging in Mary Jane.

While it isn’t a problem if you’re at home with no intention of going anywhere, it becomes an issue if you have to work or socialize. Also, if you live in a state where weed is illegal, you desperately need to hide those red eyes! If you suffer from red eye after taking cannabis, there are ways and means to prevent or treat it which we explore later in the article. First and foremost, however, let’s take a look at how you get red eyes in the first place.

A Change in Pressure

One common misconception is that red eye comes from the fact that the eyes rotate and bulge wildly when someone is high. In reality, it happens for the very reason that weed is such an effective glaucoma treatment; THC, the most prevalent and famous psychoactive compound in marijuana, is known for reducing blood pressure, dilating the blood vessels, and increasing blood circulation.

The blood pressure reduction decreases the pressure on the optic nerve. Individuals who suffer from glaucoma have excessive pressure on their optic nerve, which explains why cannabis is such an effective treatment. The positive link between marijuana and its short-term effects on glaucoma was first discovered in the 1970s. If left untreated, glaucoma could result in blindness. Although cannabis only provides relief for a few hours at a time, it is an excellent option if you’re in pain.

However, the decrease in inner-eye pressure results in the dilation of capillaries and blood vessels – when blood flow increases, small blood vessels have room to expand, and the end result is the red eyes that you see in the mirror. If you’re susceptible to red-eye after using marijuana, you’ll probably notice a greater intensity in color when you smoke a high THC strain as opposed to a low THC one. Also, the change in pressure explains why you can get red-eye from edibles; the smoke doesn’t make your eyes red, it is the cannabinoids.

What About Allergies?

It was originally assumed that the smoke from cannabis was responsible for red eyes. Tragically, however, some people are allergic to weed, and red eye is one of the symptoms. Some cigarette smokers also experience red eyes from time to time, so clearly, the human eye does not like having smoke in it. However, this theory does not explain why people experience red-eye after consuming marijuana via edibles, balms, oils, or tinctures.

Are There Any Contributory Factors?

Aside from allergies, there doesn’t seem to be anything that specifically causes red eye from marijuana use, barring the cannabinoids themselves. However, certain factors could exacerbate the effects:

  • Genetics: As our genes have an impact on everything we do, it is possible that your very DNA means a bad dose of red-eye from weed is inevitable.
  • Type of Strain: Every marijuana strain contains a huge array of chemical and organic components. They interact with one another and with metabolic processes. Therefore, it is entirely possible to suffer from red eye after using one strain, and not after using another.
  • Experience: Novice users are the most likely to suffer from red eye – over time, it is possible that you will show a greater level of resistance.
  • Dehydration: If you aren’t well hydrated, red eyes are more likely to occur. A prime example is if you get stoned and drink alcohol.

How to Fight Back Against Red Eye

One positive is that red eye from cannabis use doesn’t tend to last more than a couple of hours. Therefore, you can always wait before deciding to leave the house. If this isn’t an option because there is somewhere you have to be, there are a few things you can do:

Choose a Lower THC Strain

If you fancy a smoke but know you have to go outside afterward, choose a strain that is low in THC and high in CBD (and CBN), in order to reduce the chances of getting red eye.

Invest in Eye Drops

Visine has been classified as the ‘stoner’s friend’ ever since it was created. It constricts blood vessels, which means it can alleviate your red-eye in a matter of minutes. However, please note that overuse of these products may cause more harm than good – so use sparingly.

Use Other Vasoconstrictors

Vasoconstriction is the constriction of blood vessels, which in turn increases blood pressure. This is the ideal way to counteract the blood pressure reduction properties of weed, and is the reason why eye drops are a good choice. Other vasoconstrictors include cola, chocolate, and coffee.

Cold Compress

There are a few options when it comes to using cold compresses for red eyes; you can place cold cucumber slices on both eyes for around 15 minutes, or alternatively, you can put two green tea bags in the fridge after making tea. Take them out and place them on your eyes for 15 minutes or so to relieve the redness. Also, if you’re in a hurry, try an ice-pack across your eyes for 5 minutes, or splash cold water on your face.

Final Thoughts on Marijuana and Red-Eye

The main issue with marijuana red eye is the associated stigma. As a result, the condition can put people off weed, which is a great shame. Aside from being a clear sign that you’ve been using weed, red eye is completely harmless and only lasts a short period of time.

You should experiment with different strains and gradually reduce the THC content if you suffer from extreme red eye. Also, when you smoke weed, try and stay conscious to do it in a well-ventilated area and stay hydrated – and don’t mix marijuana and alcohol!

Finally, be sure to invest in some Visine if you plan on smoking before leaving the house – it has been a staple of stoners for over half a century, and can be a real lifesaver!

Marijuana cause Red Eye