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Why Does Cannabis Make Your Eyes Red?

It’s one of the telltale signs that someone’s been smoking cannabis – the dreaded red-eye, AKA weed eyes.

If you’re trying to keep it on the down-low, handling the smell of cannabis is a tall enough order. Add bloodshot eyes into the mix, and you’ll have a hard time fooling anyone.

But why does marijuana use cause many people’s eyeballs to turn that familiar reddish hue, and is there anything you can do to combat it?

Does Only Smoking Weed Cause Red-Eye?

If you’re hoping switching to edibles or another method of consumption might eliminate red eyes, it’s bad news.

Many people believe that it’s the smoking of the cannabis that makes your eyes red, and that would appear to have a nugget of common sense to it as smoke, in general, can cause the eyes to redden via irritation – but in fact, it’s the active ingredient and chief cannabinoid tetrahydrocannabinol (THC) in cannabis that leaves so many people looking like a recently-bereaved Basset Hound.

Regardless of your route of ingestion, if you’re one of those people who get red-eye, you will get red-eye. That’s not to say smoke isn’t a factor in why your eyes are red, but switching to another means of ingesting THC is unlikely to stop it from occurring, be it edibles, vape, bong or concentrate. It’s one of the effects of cannabis rather than the ingestion method.

What Causes Red Eye?

In simple terms, ingesting THC will cause changes in your body.

It will raise your heart rate and lower blood pressure, and low blood pressure causes dilation or widening of blood vessels and capillaries – the smaller, thinner blood vessels that connect arteries and veins. Capillaries serve as a route for oxygen, nutrients, carbon dioxide and waste products to travel to and from the body’s tissue cells.

The ocular capillaries  (those in your eyes) dilate when you use THC. In doing so, they increase blood flow while reducing intraocular pressure – and it’s this reaction that makes medical cannabis a viable treatment for glaucoma patients. The increased blood flow through those now-expanded capillaries is what causes redness in the eyes.

Basically, you’re getting additional blood flow to your eyes when you use THC. Just like increased blood flow, it can cause other symptoms such as redness of the skin and facial flushing, so it can make your eyes temporarily redden.

How Do you Stop Getting Red Eyes?

Thankfully, there are some simple steps you can take to at least reduce the severity of your cannabis-induced red-eye. There’s no guarantee they’ll work for absolutely everyone. Still, if you need to maintain or muster a semi-respectable appearance in a hurry, there are certainly ways to do that.

The following are your easiest options:

Stay Hydrated

This is a no-brainer if you’re using cannabis – whether you’re worried about red eyes or not. Since red eyes can be a sign of poor hydration at the best of times, keeping your water levels high may reduce the severity of any red-eye you do experience. Plus, it’ll stave off that nasty cottonmouth at the same time.

Try Eye Drops

It’s a neat trick that plenty of stoners have been hip to for years. But some newer smokers may not know that keeping a small bottle of over-the-counter eye drops in your pocket can provide a fast-acting antidote to the dreaded red. Available over the counter from any good Pharmacy or even off the shelf in your local supermarket, eye drops come in countless different varieties.

Look for redness-reducing eyedrops specifically, instead of the whitening variety, to help alleviate weed-related red-eye. These drops contain a decongestant ingredient that is designed to temporarily reduce swelling of the blood vessels in the eyes (which caused the redness in the first instance). Thus, reducing the red or pinkish colour in the eyeballs. Some eye drops contain lubricants to moisten the eye and protect it from drying out and causing further irritation. Resist the temptation to use these often, though, as regular use can cause additional redness.

Get Your Timings Right

Okay, it’s not a solution, more of prevention. But it makes sense to plan your cannabis use around your schedule if you have one. Wait until after your big meeting or job interview before blazing up, and you’ll eliminate the worry of being caught red….eyed…..and potentially blowing it.

Red-eye can lead to cannabis-induced anxiety, and that’s certainly not what you want before an important function. It’s not always that simple. Things can happen at a minute’s notice, but there’s nothing wrong with the ol’ ‘sensible use’ thing.

Try a Lower THC Strain

Since THC causes redness in the first place, it follows that the higher the amount of THC, the redder your eyes. Switching to low THC strains could at least minimise the severity of red-eye you suffer.

Wait it Out

Red-eye can last a couple of hours. Suppose you can’t get rid of red eyes. In that case, it’s possible to postpone whoever you’re meeting or whatever you’re doing until the redness has sufficiently dissipated – either that or simply pop a breath mint and rock up wearing your most stylish pair of shades.

Cultivation information, and media is given for those of our clients who live in countries where cannabis cultivation is decriminalised or legal, or to those that operate within a licensed model. We encourage all readers to be aware of their local laws and to ensure they do not break them.

This post is also available in: French

Duncan Mathers