Marijuana consumption affects every part of the human body, and eyes are thus no exception. Although some may find the immediate eye ‘symptoms’ rather irritating, there are several surprising ways in which marijuana may support ocular health.
Only a handful number of studies have been conducted in this area, so we can’t be completely sure about the long-term impacts of marijuana on the eye. Nonetheless, in this post, we’ll take a good look at both the short-term and long-term effects of marijuana on the human eye and whether the drug — or rather a herb these days — poses any serious threat to them.
Short-term effects
These are basically the symptoms that you experience shortly after a good smoking/vaping session:
1) Red Eye
Red eyes may be a blessing in disguise for people who often complain about feeling tension around the eyes.
Cannabis lowers blood pressure and causes blood vessels to dilate, resulting in red eyes. However, wider blood vessels imply that more blood flows into the eyes, which reduces the intraocular pressure – in a way allowing the eyes to feel relaxed.
2) Allergy
Many cannabis users experience an allergic reaction in the eyes right after smoking or vaping. The signs include redness, itchiness, inflammation, dryness and tearing.
The symptoms are typically triggered by the smoke or sometimes because of the residual molds or an allergy to the cannabis plant itself.
3) Visual processing
A combined study carried out by researchers from the University of Waterloo, the University of Auckland and Brown University in 2015 found that babies exposed to cannabis while in the womb scored significantly better in visual processing tests than those who were exposed to alcohol.
Please note that the aforesaid finding doesn’t make it a reason to consume cannabis during pregnancy. However, the finding does add some weightage to the idea that the interaction between cannabinoids and the human endocannabinoid system could help the eyes and brain make better sense of visual data.
4) Enhanced night vision
A piece of research from the year 2016 states that tetrahydrocannabinol (THC) — the compound that causes you to experience a ‘high’– binds with CB1 receptors in the brain and improves a person’s ability to see in low-light conditions.
Another small study compared the effects of traditional kif (a mixture of marijuana and tobacco) with synthetic THC in 3 Moroccan individuals. The experiment found that moderate doses of marijuana helped improve night vision.
Long-term effects to treat conditions
Of late, a growing body of evidence suggests that cannabis may hold the key to treat the following serious conditions:
1) Neurodegenerative blindness
A group of researchers treated lab rats suffering from retinitis pigmentosa with synthetic THC for a period of 3 months. The results showed that the rats treated with the cannabinoid boasted an impressive 40% more photoreceptors than their nontreated counterparts.
You can read the entire study here.
2) Glaucoma
Glaucoma is among the leading causes of blindness in the world. Notably, scientists have been studying the use of cannabis for glaucoma since as early as 1970 and the results look promising.
In one of the studies, researchers inferred that inhaled cannabis could successfully treat the intraocular pressure that contributes to pain and leads to degeneration. The relief, however, lasts for only 3-4 hour; hence, the doses need to be repeated.
