How Marijuana Can Actually Improve Night Vision

Bloodshot eyes, droopy eyelids, and a glossy sheen, are all commonly associated effects of marijuana on a person’s eyes, and if you’ve ever seen a truly stoned individual you would know each one is true.

With that in mind, it’s easy to assume marijuana would harm a person’s vision. Yes, cannabis is used to treat eye-related illnesses like cataracts, but that doesn’t mean marijuana actually improves eyesight or night vision. It’s not as if smoking up will turn your retinas into night vision scopes, right?

Except, in light of new research coming out of Montreal, Quebec, that assumption may be wrong; marijuana has been found to improve night vision… at least in tadpoles.

A team of researchers headed by Montreal Neurological Institute of McGill University neurologist  Ed Ruthazer recently examined the effects of cannabinoids (marijuana’s active ingredient, most notably THC) on the retinas of tadpoles.

During their experiments, the team exposed a group of tadpoles to cannabinoids and then examined how the chemical compound interacted with the larval stage amphibian’s retinas. Ruthazer and his team assumed what the rest of us would, that the cannabinoids would decrease the level of night vision in tadpoles.

In practice, however, the opposite was found to be true. The tadpoles given cannabinoids were actually shown to have improved night vision, as the drug positively influenced the animal’s retinal ganglion cells, which tell the brain that light (and thus sight) is present.

To get a bit more technical, type 1 cannabinoid receptors (or simply CB1Rs), which are actively present in the retina of vertebrates were able to send signals at a faster rate thanks to the influence of cannabinoids. Quoting the study’s abstract, “CB1R activation markedly improves visual contrast sensitivity under low-light conditions.”

All in all, tadpoles exposed to cannabinoids were able to escape danger and demonstrated a generally improved level of eyesight in a dark environment.

The study’s findings were recently published in the academic journal eLifeSciences, and mark a both cognitive and scientific shift from what people may assume about marijuana. Namely, we now know that cannabis can improve night vision and eyesight.

But what about humans? Would cannabinoids even have the same effect on a person as it did on the tadpoles? Will lighting up a joint soon be seen as a smart thing to do when it’s dark and rainy on the road?

Nothing can be said for sure (except that smoking-while-driving isn’t going to be a good thing anytime soon) but there is some evidence to suggest that what occurs in a frog’s eye when exposed to cannabinoids may happen in the human eye.

Ruthazer told the Montreal Gazette that “structurally, there is an evolutionary link and some evidence that suggests it just may work,” but more research needs to be done on the topic before anything can be confirmed.

Still, as attitudes towards marijuana shift and Canada’s government already planning out the logistics of legalization, this connection between improved eyesight and cannabinoids may become a hot new topic of research.

Featured image courtesy of: Kamil Porembiński