From Current Opinion in Ophthalmology:
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.