Researchers have found that the decrease in intraocular pressure (IOP) begins shortly after inhaling cannabis and can reach up to 16%
According to a new study published in the journal Frontiers in Medicine, inhaling cannabis "significantly" reduces intraocular pressure (IOP) for up to four hours. The study was conducted by an international team of researchers from the United States and Italy, according to the National Organization for the Reform of Marijuana Laws (NORML), which assessed the association between plasma THC levels and IOP.
Study participants (healthy adults) consumed cannabis with levels ranging from 6% to 14% THC. The researchers then measured IOP and plasma THC levels every 30 minutes for the first hour after dosing, then every hour for four hours, comparing these measurements to baseline.
"The results of this study indicate that in healthy adult subjects, inhaled THC significantly reduces IOP and that this effect correlates with plasma THC levels," the researchers wrote, adding that the reduction in IOP began soon after inhalation and could reach 16%.
Further research is needed to determine the effectiveness of THC in lowering IOP for eyes with ocular hypertension and glaucoma, the researchers concluded.
Glaucoma, the second leading cause of blindness worldwide, causes increased IOP pressure and progressive loss of vision. There is no cure and this disease can affect people of all ages.
The discovery of the effects of cannabis on IOP dates back to the early 1970s, when researchers affiliated with the University of California, Los Angeles (UCLA) reportedly began studying the "red-eye" effect of cannabis to aid Drug Enforcement. US administration to stop consumers.
Instead, they discovered that THC reduced eye pressure from 25 to 30%.
Research dating back more than 50 years has shown that THC reduces intraocular pressure, and nearly all US state-specific medical access laws list glaucoma as a qualifying medical condition, according to NORML. Yet the federally illegal plant has not yet been approved by the American Glaucoma Society or the Glaucoma Research Foundation as a treatment option.
Other studies have found that using cannabis to treat glaucoma has some downsides, including lower blood pressure, which may decrease blood flow to the optic nerve and counteract the benefits of lowering IOP.