Marijuana and Glaucoma
"Marijuana and THC have been shown to reduce IOP [intraocular pressure] by an average of 24% in people with normal IOP who have visual-field changes. In a number of studies of healthy adults and glaucoma patients, IOP was reduced by an average of 25% after smoking a marijuana cigarette that contained approximately 2% THC." — Marijuana and Medicine: Assessing the Science Base, National Academy of Sciences, Institute of Medicine (1999)
Published Research Articles
Dronabinol and Retinal Hemodynamics in Humans — American Journal of Ophthalmology — Volume 143, Issue 1, Pages 173-174 (January 2007)
Purpose: To investigate the effects of oral cannabinoids on retinal hemodynamics assessed by video fluoresce in angiography in healthy subjects.
Methods: In a self-experiment, the cannabinoid dronabinol (delta-9-tetrahydrocannabinol [THC]) was administered orally to eight healthy medical doctors (7.5 mg Marinol; Unimed Pharmaceuticals, Chicago, Illinois, USA). At baseline and two hours after dronabinol intake, intraocular pressure (IOP) was measured and retinal hemodynamics were assessed by fluorescein angiography. The retinal arteriovenous passage time was determined on the basis of dye dilution curves by means of digital image analysis in a masked fashion.
Results: Dronabinol resulted in a significant IOP reduction from 13.2 +/- 1.9 mm Hg to 11.8 +/- 2.0 mm Hg (P = .038). The retinal arteriovenous passage time decreased from 1.77 +/- 0.35 seconds to 1.57 +/- 0.31 seconds (P = .028). Systemic blood pressure and heart rate were not statistically significantly altered.
Conclusions: Cannabinoids, already known for their ability to reduce IOP, may result in increased retinal hemodynamics. This may be beneficial in ocular circulatory disorders, including glaucoma.
Effect of Sublingual Application of Cannabinoids on Intraocular Pressure: A Pilot Study — Journal of Glaucoma Volume 15(5) October 2006 pp 349-353
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 (Delta-9-THC) and cannabidiol (CBD).
Patients and Methods: A randomized, double-masked, placebo-controlled, 4 way crossover study was conducted at a single center, using cannabis-based medicinal extract of Delta-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 Delta-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.
Results: Two hours after sublingual administration of 5 mg Delta-9-THC, the IOP was significantly lower than after placebo (23.5 mm Hg vs. 27.3 mm Hg, P=0.026). The IOP returned to baseline level after the 4-hour IOP measurement. CBD administration did not reduce the IOP at any time. However, the higher dose of CBD (40 mg) produced a transient elevation of IOP at 4 hours after administration, from 23.2 to 25.9 mm Hg (P=0.028). Vital signs and visual acuity were not significantly changed. One patient experienced a transient and mild paniclike reaction after Delta-9-THC administration.
Conclusions: A single 5 mg sublingual dose of Delta-9-THC reduced the IOP temporarily and was well tolerated by most patients. Sublingual administration of 20 mg CBD did not reduce IOP, whereas 40 mg CBD produced a transient increase IOP rise.
Marijuana Smoking vs Cannabinoids for Glaucoma Therapy — Archives of Ophthalmology 1998;116:1433-1437
Objective: To discuss the clinical effects, including toxicological data, of marijuana and its many constituent compounds on the eye and the remainder of the body. A perspective is given on the use of marijuana and the cannabinoids in the treatment of glaucoma.
Results: Although it is undisputed that smoking of marijuana plant material causes a fall in intraocular pressure (IOP) in 60% to 65% of users, continued use at a rate needed to control glaucomatous IOP would lead to substantial systemic toxic effects revealed as pathological changes.
Conclusions: Development of drugs based on the cannabinoid molecule or its agonists for use as topical or oral antiglaucoma medications seems to be worthy of further pursuit. Among the latter chemicals, some have no known adverse psychoactive side effects.