Purpose: The purpose of this study was to assess the effect on intraocular pressure (IOP) and the safety and tolerability of oromucosal administration of a low dose of delta-9-tetrahydrocannabinol (D-9-THC) and cannabidiol (CBD). Patients and Methods: A randomized, double-masked, placebocontrolled, 4 way crossover study was conducted at a single center, using cannabis-based medicinal extract of D-9-THC and CBD. Six patients with ocular hypertension or early primary open angle glaucoma received a single sublingual dose at 8 AM of 5 mg D-9-THC, 20 mg CBD, 40 mg CBD, or placebo. Main outcome measure was IOP. Secondary outcomes included visual acuity, vital signs, and psychotropic effects....