The study was reported Dec. 14 in the journal Investigative Ophthalmology & Visual Science .
The study, which was conducted in mice, specifically found that CBD caused an increase in pressure inside the eye of 18 percent for at least four hours after use.
Tetrahydrocannabinol, or THC, the primary psychoactive ingredient of marijuana, was found to effectively lower pressure in the eye, as has been previously reported. But the study found that the use of CBD in combination with THC blocked this effect.
Specifically, the study found that male mice experienced a drop in eye pressure of nearly 30 percent eight hours after exposure to THC alone. A lower pressure drop of 22 percent was also observed after four hours in male mice.
The effect was weaker in female mice. This group experienced a pressure drop of only 17 percent after four hours. No difference in eye pressure was measured after eight hours.
The results suggest that females may be less affected by THC, though it isn’t clear whether this extends to the substance’s psychoactive effects.
“This difference between males and females – and the fact that CBD seems to worsen eye pressure, the primary risk factor for glaucoma – are both important aspects of this study,” Straiker said. “It’s also notable that CBD appears to actively oppose the beneficial effects of THC.”
It is worrisome if CBD does actually increase eye pressure in humans (or counteracts the effects of THC). Let us hope that is not the case.
Still, THC showed very positive effects, which is great news.
Here’s the original study in case you want to pick it apart: https://iovs.arvojournals.org/article.aspx?articleid=2718702