Can Cannabis Give You Night Vision?

For centuries, cannabis has been coveted for its medicinal properties. More than simply a relaxant, it’s emerged as a bona fide treatment for a myriad of health concerns, from depression and anxiety to back pain and arthritis. Now, the green leafy plant has landed itself in the spotlight for yet another feat, with new research showing that cannabis could actively enhance night vision.

A Caribbean cocktail

The revelation began 25 years ago, when a pharmacologist named M. E. West noted that local Jamaican fisherman who regularly smoked cannabis or consumed rum brewed with the leaves and stem of the plant had what he described as “an uncanny ability to see in the dark.” He observed them navigating their boats through coral reefs with remarkable skill, despite the fact that lighting was non-existent and conditions were treacherous.

This led him to the conclusion that an external source was improving their night vision, which he identified as cannabis. After running his theory past the fishermen they informed him that Moroccan mountain tribes also experience similar night vision improvements after smoking hashish. In 2002 a research team travelled to Morocco’s Rif Mountains and used a sophisticated method to measure the sensitivity of night vision, before and after hashish. The results backed West’s theory, and confirmed that cannabis improved night vision in all subjects.

Modern medicine and marijuana

Now, new research is offering the medical sphere even harder evidence, with scientists from the Montreal Neurological Institute honing in on the cellular mechanism that triggers the improvement of night vision. According to the study published in open access journal eLife, the natural drug makes cells in the retina more sensitive to light. From a medical perspective, this could see cannabis emerge as an exciting new treatment for degenerative eye diseases like retinitis pigmentosa.

Swapping humans for tadpoles

Interestingly, the Montreal Neurological Institute based team shunned stoned fishermen in favour of transparent African clawed toad tadpoles when conducting their research. Using microelectrodes the team measured how retinal ganglion cells respond to light, and found that sensitivity significantly increased under the influence of the synthetic cannabinoid.

The rate at which they fired to both bright and dim light stimuli jumped, with closer analysis revealing that this was due to the inhibition of the NKCC1 protein. As a co-transporter protein, NKCC1 transports sodium, potassium and chloride ions in and out of cells, which determines the electrical properties of retinal ganglion cells. The study found that cannabinoids reduce the concentration of chloride ions, which makes them more sensitive than usual to light. 

For more information on how marijuana is making its mark in the medical arena, ‘Evaluation of Evaporative Techniques in the Extraction and Preparation of Cannabis Oil’ is a must read article. It explores the Californian tetrahydrocannabinol (THC) oil industry, and the next generation techniques being used to extract and refine the medicinal by-product.