If you have to wear shades in public or walk around your house at night without the lights on, it might not be because you are high. Well, it is, but not because you are stoned. It turns out, research is showing that cannabis helps you see better in the dark.
Humans and night vision
As probably the most highly evolved species on the planet, we get a lot of perks. Speech, logic, creativity, and love, to name a few. But our more primordial senses, such as those needed to hunt at night, have fallen far short of other creatures, like wolves or owls. At limited light levels, we drop to black and white vision far quicker.
Technology has come a long way to compensate, giving us night vision goggles and scopes. But what is the science behind natural night vision? Other creatures have the added benefits of special reflectors in the backs of their eyes. But for us, it boils down to signal sensitivity between the eye and brain.
Man’s history of natural compensation
There are some tricks you can use to enhance or protect your night vision sensitivity. Pirates long ago didn’t use eyepatches just because of injuries. The actually used them to keep one eye trained to the dark of a ship so they could go topside and back without having to lose that adjustment.
Even in modern history, soldiers have proved that the better vision wins. An old WWI superstition was to never light more than one cigarette with the same match. The reason? It gave snipers time to hone in and take a shot.
More recently, soldiers use colored lenses on flashlights to limit the spectrum to red. It let them stay sensitive, and enemies have a harder time focusing on it from a distance.
But now scientists have rediscovered another secret of staying keen eyed in the dark. It isn’t some risky surgery either. It turns out that using cannabis increases night vision.
Discovering proof of canna-vision
In 2004, researchers observed that Moroccan fisherman had a time honored tradition of smoking cannabis while fishing at night. The fisherman boasted that it did more than just pass the time pleasantly, it improved their vision on the water in the dark.
The researchers, ever skeptical, put the stoned fisherman through a series of vision tests and were astounded. The more the men smoked, the better their vision became.
Verifying it with… baby frogs?
A study published this year in eLife supports the findings. In it, the Montreal Neurological Institute at McGill University used tadpoles treated with cannabis to test the hypothesis.
Edward Ruthazer, a professor on the team, said,
We’re a lab that studies the development of circuits in the brain. We use tadpoles because they’re transparent. We can actually look at the brain cells in the intact animals and watch them remodel over time and form connections.
It’s known that cannabinoids are important in some aspects of brain development, so we wanted to look at them in our system to see and record the functional changes in connectivity [when they’re introduced].
Rather than the decrease they expected, typical of long held myths of cannabis-reduction of faculties, they found that it actually makes the eye more sensitive to visual stimuli.
Cannabis and your eyes
We all know that cannabis tends to dilate pupils. Unfortunately, it’s one of the tell-tale signs for officers of THC use. Why? Because the old flashlight trick tests your eye’s reflexes. A cannabis user’s eyes will be naturally dilated larger, and recover faster from a bright light than the eyes of a sober person.
Conversely, in bright daytime conditions, our eyes contract smaller than a normal eye would. But that sensitivity extends beyond just pupil dilation.
It turns out, according to Ruthazer’s study, that THC acts on CB1 receptors in the brain that increase eye function. These neurons alert cells in the eye to increase the signal they send to the brain when detecting light. Increasing the body’s own endocannabinoids, like anandamide, produces the same result.
How early man corroborates this
This all goes back to explain primitive hunter physiology. Anandamide, nicknamed the runner’s high, is almost identical in effect to THC. So for those who had to chase food into the dark, the chase helped their bodies prepare the eyes for the search.
After all, if you are going to hunt prey at night, or avoid becoming dinner to other predators on the prowl, fast legs, and keen eyes are your two best survival tools.
For idle fishermen, however, cannabis works just as well to make eyes sharp in limited light. Even better, it does so without rocking the boat. Maybe Bob Marley had a hidden message in his lyrics? Now you have an even better reason to take weed with you on a camping trip.