Cannabis may have the ability to improve one's eyesight. One way cannabis may be able to do so is by reducing intraocular pressure (IOP). The National Eye Institute has found THC lowers IOP for three to four hours when ingested orally, sublingually, or ocularly. Researchers have also found the presence of THC receptors in the eye's tissue, and evidence that cannabinoids can save optic nerve cells through a neuroprotective mechanism. Another study from the University of Alicante in Spain found cannabinoids may slow the progression of blindness. Researchers used synthetic THC throughout tests in rats with retinitis pigmentosa (RP), a genetic degenerative eye disease, and found the cannabinoid prevented further vision loss. In 90 days, rats that received the THC gained better scores on vision tests and acquired 40% more photoreceptors than those that did not. Additionally, researchers found THC protected inner layers of the retina.
Cannabis may also help with night vision. In one study, scientists used a night vision measuring machine, a 2:1 ratio of high-grade sifted cannabis and tobacco, and a traditional sebsi pipe, and asked Moroccan fisherman to consume the concentrated herb. According to the Journal of Ethnopharmacology, volunteers displayed consistent night vision improvements during testing. Jamaican fisherman have experienced similar improvements. Lastly, cannabis can impact visual processing within the brain. Researchers from the University of Waterloo in Ontario found babies who were exposed to cannabis while in the womb had better vision, and found they could better track moving objects. That being said, cannabis may have other negative impactions on prenatal development, so cannabis is not recommended until more research exists.
This information has been provided by Merry Jane and approved by our Chief Medical Officer.