Cannabis and Eyesight

Published: 2022-10-24

Destroying the myths that mushrooms improve eyesight and figuring out what doses of marijuana are needed for patients with glaucoma. Scientific pros and cons of experiencing narcotics in ophthalmology.

Cannabis and Eyesight

Cannabis and Eyesight


There’s a long-standing rumor that cannabis helps us see better in the dark, but let’s look at it from a scientific point of view.

Scientists at the Montreal Neurological Institute have studied the effects of narcotics on the eyes. True, it was done on frogs…

As one American psychologist said, “Scientists, apparently, think that mankind has descended from the white mouse.”

But now it appears that Homo sapiens came from the African Clawed Frog, as well.

First, the Canadians gave the tadpoles synthetic cannabinoid in order to test its effects on eye tissues, and then with the help of microelectrodes recorded how the retinal cells responded to light.

The rumor proved true! Cannabinoid made the cells more sensitive to light. Then, to see if this affected vision, the tadpoles were placed in a petri dish and observed on how they reacted to dark spots in different levels of light.

Usually, the innocent tadpoles swim away from the dark spots, assuming they are predators.

In normal lighting, there wasn’t a difference between the “stoned” tadpoles and the sober ones.

But in dim lighting, the former more actively avoided these dark spots; their vision in the dark had improved.

I don’t know what prevented these brave Canadian scientists from taking a group of volunteers and giving them some pot to smoke, or even some edibles. Perhaps it would be difficult to get a grant for this experiment, and using tadpoles helps it to appear more scientific.

It is unknown whether cannabis can make humans eagle-eyed, as well, but there are many long-standing rumors about it.

Scientists are nevertheless charged with optimism, and believe that further research can help find more effective treatments for macular degeneration and glaucoma.


There’s an even more powerful rumor that psilocybin mushrooms can improve vision. The famous ethnobotanist, mystic, psychonaut, lecturer and author Terence McKenna even has an interesting theory on the evolution of consciousness, based on this idea, and everyone knows that hallucinogenic mushrooms have sensory effects, particularly in regard to vision and hearing.

Colors are brighter and have more contrast. It’s true that you’ll see often halos around back-lit objects, perspective distortion, and a glowing haze in the air, moving surfaces that appear to flow from one place to another, ripples, pulses or deformities, kaleidoscoping textures, color-changing objects, tracers, and many other things that personally remind me of the “special effects” of cataracts.

It all depends on the dose, and that’s why vitamin companies are popping up (like mushrooms) that sell small, homeopathic doses of these psychoactive substances. I think it can be compared to wine. If you have a sense of moderation, wine can beautify your life – if you don’t, it can pull you under. Just like anything else. “There is nothing that couldn’t be hell.” (Borges)



The internet is full of contradictory data, so I turned to a sacred source – the site of the American Academy of Ophthalmology. I’ll translate a piece for the ordinary mortals:

“The idea of the effectiveness of marijuana in the treatment of glaucoma has its roots in the 70s. Studies showed that marijuana use reduced intraocular pressure. However, this is only for 3 to 4 hours.

Glaucoma needs to be under control 24 hours a day, which means you’d have to smoke marijuana 6-8 times a day. But it doesn’t only affect the eyes – also your ability to drive a car, operate machinery, and be generally adequate.

This isn’t the only side effect. Marijuana cigarettes contain hundreds of components that are harmful to the lungs. Moreover, at high doses, it affects short-term memory and concentration.

Intraocular pressure isn’t the only factor that leads to damage of the optic nerve, either. Recent research has shown that glaucoma is a neurological disease like Parkinson’s or Alzheimer’s”.

Patience! It will end soon.

“There is evidence that a reduction in blood flow to the optic nerve can also harm patients with glaucoma. And marijuana not only reduces intraocular pressure, but also blood pressure. As a result, it can potentially restrict blood flow to the optic nerve, thus canceling out the advantages from having reduced intraocular pressure.”

I’m not going to argue with the Academy. I’m the little guy. However, it is unclear why they only discuss smoking. There are chocolates, cookies, and all other kinds of fun that aren’t harmful to the lungs, and I think last longer.

It would be nice to investigate these popular delicacies’ impact on vision. Again, only low doses! I’m a fan of moderation.


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Text and photo: SebastianVaro