Why does weed make your eyes red?
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- Under pressure: lower blood pressure and dilated capillaries
- Do edibles make your eyes red?
- The redder the better?
Among the most common effects of marijuana use (and telltale signs you’ve recently partaken) is red, bloodshot eyes. It’s to be expected, sure, but that doesn’t answer the mysterious question pondered by generations of stoners: why does weed make your eyes red?
For weed novices, the onset of bloodshot eyes could cause a panic-induced internet search asking “ can smoking weed damage your eyes? ” Thankfully, as those who regularly consume cannabis can tell new users, there are no serious health risks associated with your sudden red-eyed circumstance. You’re probably not experiencing an allergic reaction or some bigger complication. Some might poke fun or chastise you for sporting your so-called “ weed eyes ” in public, but otherwise, it’s a completely natural occurrence that transpires after smoking cannabis.
In fact, your eyes turning red has nothing to do with the act of smoking at all.
Under pressure: lower blood pressure and dilated capillaries
After consuming a cannabis-based product (flower, concentrate, edible, etc.), users generally experience an increase in heart rate and blood pressure. This effect is due to the plant’s cannabinoids, which are chemical compounds responsible for some of the therapeutic and medicinal benefits of cannabis, and their initial interaction with the body. This rise in blood pressure and heart rate is comparable to normal physical activities like exercise or sex.
It generally takes about five to ten minutes for users’ heart rates to return to normal and for blood pressure to begin to decrease. As the blood pressure lowers, the blood vessels and capillaries dilate, including the ocular capillaries . The dilation of ocular capillaries causes increased blood flow to the eyes, which results in your eyes turning red and also reduces intraocular pressure.
The dilation of ocular capillaries causes increased blood flow to the eyes, which results in your eyes turning red in the process, and also reduces intraocular pressure. Photo by: Gina Coleman/Weedmaps
In fact, according to Dr. Melanie Bone, a board-certified OB-GYN who practices in West Palm Beach, Florida, “It’s cannabis’ ability to reduce intraocular pressure in the eyes that makes it a potentially viable treatment for glaucoma , a group of eye disorders that causes damage to the optic nerves which can eventually lead to blindness. It also happens to explain why your eyes become bloodshot after smoking cannabis.”
Evidence that the THC found in cannabis can lower intraocular pressure (IOP) is a major reason why many glaucoma patients have attempted to use medical marijuana to treat and relieve symptoms of the disease. It’s important to know that some studies have contradicted or added a caveat to the claim that cannabis is beneficial for glaucoma. For instance, a 2018 study conducted at Indiana University found that cannabidiol (CBD), the non-intoxicating cannabinoid found in marijuana, could potentially worsen the condition by increasing eye pressure . More research into the use of cannabis for glaucoma treatment is needed.
Do edibles make your eyes red?
Similar to smoking cannabis, ingesting edibles could also make your eyes turn red. Again, this depends on the amount of THC consumed. Remember, it’s not the smoke itself that makes your eyes red, but rather the ability that cannabinoids have to lower blood pressure, causing blood vessels and capillaries to dilate.
The redder the better?
The amount your blood pressure is lowered and how red your eyes become depends on the amount of THC you consume.
Tetrahydrocannabinol (THC), the most common cannabinoid in the plant, is responsible for the intoxication associated with smoking cannabis. The greater the concentration of THC in a cannabis product, the stronger the effects and the redder your eyes become.
The greater the concentration of THC in a cannabis product, the stronger the effects and the redder your eyes become.
So, red eyes can act as a sign that your cannabis has a high cannabinoid content (i.e., it’s potent). In other words, if your eyes are noticeably bloodshot after consumption, there’s a good chance you’ve landed yourself some highly potent weed.
Other than being a dead giveaway that you’ve recently consumed cannabis, you have no reason to be concerned about the redness of your eyes. Cannabis-induced eye redness will typically only last a few hours and can easily resolve if you have the right tools at your disposal.
It isn’t a bad idea to have eye drops (or some sunglasses) on hand. Look for eye drop brands that are specifically designed to reduce eye redness. There are other methods that could potentially help combat cannabis-induced bloodshot eyes, including staying hydrated, washing your face and eyelids with cold water, or simply consuming cannabis products with lower THC levels.
Ever wonder why using marijuana or cannabis makes your eyes red or bloodshot? Discover why weed gives you bloodshot eyes.
Why Smoking Cannabis Causes Red, Bloodshot Eyes
Red eyes are typically a classic, telltale giveaway that someone’s smoked cannabis. For certain individuals, it’s a guaranteed occurrence, while for others who seem to be less sensitive, red eyes may come and go depending on the quantity or quality of the cannabis they consume.
What causes this common reaction? A few factors may come into play.
The primary cause for reddening of the eyes after smoking cannabis also happens to be the main reason that the plant is famous as a treatment for glaucoma. In short, THC lowers blood pressure, which in turn causes blood vessels and capillaries to dilate. The ocular capillaries dilate, which increases the flow of blood to the eyes and reduces intraocular pressure. Increased blood flow creates the redness, while the decrease in pressure is the same effect that benefits glaucoma patients.
This reaction explains the variations in the intensity of red eyes. An individual may smoke a low THC strain one day and experience little to no red eyes, while the next day their eyes may be beet red after ingesting a high THC strain.
Additionally, this explanation accounts for why red eyes can still occur even with the lack of smoke, such as when eating edibles. It’s not the smoke that makes your eyes red, but the cannabinoids.
That being said, it’s possible for some to have an allergy or irritation to cannabis or to smoke in general, and have increased redness of eyes for this reason. However, for these sensitive individuals, the experience would likely be a universal reaction to smoke, be it cannabis, tobacco, or perhaps even incense.
How to Get Rid of Red Eyes from Cannabis
The cause for red eyes from cannabis is a harmless, even perhaps beneficial one, but that doesn’t necessarily make it a welcome reaction to all. There are a few simple steps one can take to minimize or reduce redness of eyes during or after smoking.
- Opt for low or no THC strains.Strains high in CBD, CBN, and the like may be a desirable alternative for those looking to lessen red eyes when toking.
- Have eye drops on hand, especially brands specially formulated to reduce eye redness.
- Stay hydrated by drinking plenty of water. Increasing your fluid intake may help alleviate the dryness you experience.
- Simply let it run its course and plan smoke sessions for leisurely moments spent at home. Ultimately, red eyes are not harmful and come with no negative outcomes (other than the dated stigma associated with them).
The next time a glance in the mirror reveals a pair of bright red eyes after a smoke sesh, just remember that a little extra blood flow is nothing to worry about!
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