Weed science has come along the way in the last few decades. Two generations ago our understanding of weed was pretty much that if you rolled up a bunch of it in a little piece of paper and lit one end of it, you would get high. These days we have purified decarboxylated concentrates made from hydroponic-perfected buds. We get high in ways our parents never even imagined possible. We’re even unlocking the cannabis genome.

And yet some simple weed problems still populate our weed understanding. Like, for instance, how do you keep your eyes from getting squinty and bloodshot? And why do they get like that anyway?

Well, never fear. The weed scientists are here. Let’s tackle these problems one at a time.

Bloodshot Eyes

Cannabis lowers blood pressure. The effect this has on your eyes is to widen your veins and capillaries so that blood flows more easily. This is the reason why doctors sometimes recommend cannabis to relieve ocular pressure in glaucoma patients. It also means there is more blood in your eyes than usual, which can give you that bloodshot look.

The reason why some strains give you bloodier eyes than others is the THC count. THC is the cannabinoid that is worse for bloodshotness (or better for glaucoma, depending on your point of view).

Some people get really bad bloodshot eyes when they smoke, so bad that even eye drops like Visine don’t help. You could also drink lots of water (to keep your eyes moist) or smoke low-THC varieties of cannabis (if that’s your sort of thing).

Squinty Eyes

There’s a little less science on this. In fact, we have to go by folk wisdom to answer it. But basically, there are three different reasons we know of why cannabis makes you squint.

  1. It dries your mucus membranes, which makes your eyes dry. This is the same reason you get cottonmouth, and it’s often unrelated to being dehydrated.
  2. It makes your eyes more sensitive to light, which makes you squint (for duh).
  3. Cannabis makes you sleepy and fatigued. The look that someone gets when they’re really, really stoned isn’t just squinty, red eyes. It’s like the muscles on their face don’t work right, not dissimilar from someone who just woke up.

There you have it. Hope you just got some knowledge because knowledge is power.