Many marijuana users report red eyes as an effect of using cannabis, although this side effect usually only lasts several hours to a full day.
Marijuana can produce red eye effects due to vasodilation caused by THC and other cannabinoids. When THC enters your bloodstream through the endocannabinoid system, it causes temporary spikes in heart rate and blood pressure before eventually subsiding and leading to dilation of ocular capillaries resulting in red-tinged veins.
Increased Blood Flow
THC enters your bloodstream, it causes your ocular capillaries (tiny blood vessels that run through your eyes) to dilate, increasing blood flow to them and making them look redder than usual. Eye redness is a common side effect of marijuana consumption regardless of method used for consumption.
THC attaches to CB1 receptors in your body and causes vasodilation that leads to red eyes. Although this phenomenon may last several hours, eventually your body metabolizes THC and your blood pressure returns to normal.
To help reduce eye redness, you can try using over-the-counter lubricating drops with ingredients such as tetrahydrozoline to constrict blood vessels and decrease redness. Staying hydrated and limiting smoke exposure will also reduce eye irritation from cannabis smoke exposure; however if red eyes persist or accompany other symptoms it may indicate serious health concerns that require medical advice.
THC
Most marijuana users know that red eyes are an unmistakable telltale sign of cannabis consumption. Redness, along with elevated heart rate and blood pressure levels, results from THC’s effect on various systems within your body–of which the eyes are an integral component.
THC interacts with cannabinoid receptors within the endocannabinoid system to trigger dilation or widening of blood vessels – including those found within the whites of our eyes – inducing dilation or widening. When this happens, blood vessels appear through our whites giving an eye a reddish or pinkish tint when dilatant blood vessels become visible through them.
THC’s effects aren’t limited to smoking cannabis – red eyes may occur from any method of consumption including tinctures, edibles, vape cartridges or vape pens. While red eyes from marijuana consumption tend to be harmless and short-term effects are usually harmless if hydrated regularly or eating something salty to temporarily raise blood pressure may help lessen their impact on eyes.
Irritation
As cannabis becomes more widely available, people are becoming increasingly curious about its effects on the body. Unfortunately, however, many remain misinformed and misled about this miraculous plant; one such myth being that marijuana causes red eyes.
As much as smoking cannabis may lead to red eyes, edibles containing THC can also contribute to them. When you take in THC-laden edibles, your heart rate and blood pressure rise, leading to dilation of ocular blood vessels resulting in redder eyes.
If red eyes are an adverse side effect of cannabis use, there are various remedies that can help alleviate them. Eye drops sold over-the-counter can constrict blood vessels to help reduce their appearance of redness while cold compresses or artificial tears may soothe and moisturize eyes. Furthermore, drinking plenty of water to remain hydrated and avoid dryness that contributes to eye irritation is key to alleviating its side effects.
Blepharitis
Red eyes associated with marijuana use are usually harmless; however, if they become an ongoing problem it may be wise to consult a doctor and ensure there are no underlying conditions present. Meanwhile, several simple remedies can help: over-the-counter eye drops can reduce redness by constricting blood vessels and reducing inflammation; cold compresses or artificial tears may offer soothing effects as can staying hydrated by drinking lots of water regularly.
No matter how a person consumes cannabis or edibles, both can lead to red eyes. This is due to THC affecting an individual’s endocannabinoid system regardless of which method they choose for ingestion, leading to blood pressure drop and an increase in ocular capillaries which then results in red and dilated eyes accompanied by pupil dilation as blood vessels dilate from increased perfusion pressure; pupil dilation itself acts as a giveaway of marijuana use and pupil size can serve as an indicator. As soon as THC effects wear off, ocular capillaries return to normal levels, bringing relief for red eyed individuals!