Purpose of review: The purpose of this article is to review the current status of cannabis in the treatment of glaucoma, including the greater availability of marijuana in the USA.
Recent findings: The potency of marijuana, as measured by the concentration of Δ-tetrahydrocannabinol, has increased from ∼2 to 3% in the 1970s to ∼20% today. Many US states have passed laws allowing either medicinal or recreational use of marijuana.
Summary: The pharmacology of marijuana and its effect on intraocular pressure has not changed since the research in the 1970s and 1980s. Marijuana is an effective ocular hypotensive agent. However, cardiovascular and neurological effects are observed at the same dose, and may theoretically reduce the beneficial effect of lowering intraocular pressure by reducing ocular blood flow. The clinician must be cognizant of this potential in diagnosis, prognosis, and therapy.