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Overview of Glaucoma

Glaucoma is an eye condition characterized by abnormally high pressure in the eye, which gradually causes damage to the optic nerve. According to Mayo Clinic, glaucoma is one of the leading causes of blindness in the United States.

The vision loss caused by glaucoma cannot be recovered and the most common form of glaucoma has zero warning signs. The damage to the optic nerve is so gradual that most don’t notice the change in vision until the condition is at an advanced stage. Early detection through regular eye exams and a test that measures eye pressure are necessary for glaucoma to be diagnosed early enough before permanent damage can be done. Those who are diagnosed with the condition will need regular treatment to lower eye pressure for the rest of their lives.

The elevated eye pressure is the result of a buildup of fluid called aqueous humor that flows throughout the eye. The fluid normally drains, but when it’s overproduced or doesn’t drain properly, pressure builds.

There are two types of glaucoma conditions, including open-angle glaucoma and acute angle-closure glaucoma. Open-angle glaucoma is the most common form of the condition. Acute angle-closure glaucoma can be accommodated with severe headache, eye pain, and nausea and vomiting.

Since glaucoma isn’t curable, treatment focus is on keeping the pressure lower in the eye through medications.

Findings: Effects of Cannabis on Glaucoma

Over multiple decades, scientific research has proven that cannabinoids are effective at decreasing intraocular pressure11. In addition, the compounds found in cannabis feature neuroprotective and vasodilation properties, which further assist in the conservative treatment of glaucoma10. The cannabinoids found in cannabis, including tetrahydrocannabinol (THC), activate endocannabinoid receptors CB1 and CB212. These endocannabinoid receptors are located in the structures of the eyes and are responsible for the formation and outflow of aqueous humor10.

Studies have demonstrated cannabinoids have efficacy at lowering intraocular pressure1,12. One study found that smoking cannabis lowered blood pressure, which led to a decrease in intraocular pressure, within 60 to 90 minutes of inhalation7.

For patients interested in avoiding the psychoactive effects of smoking cannabis, topical cannabinoid applications have also proven effective at decreasing ocular pressure5. In one study, applying THC oil directly to the eyes of participants with high blood pressure resulted in the lowering of systolic blood pressure, which researchers concluded may lead to a decrease in intraocular pressure8. In another, applying cannabinoid directly to the eye decreased intraocular pressure within the first 30 minutes with maximal reduction being reached in 60 minutes12. One study that applied cannabinoids directly to the eyes of rabbits recorded decreased intraocular pressure within 1.5 hours of administration and the effects lasted for more than 6 hours. In addition, the eye to which the cannabinoid had not been administered also experienced a decrease in intraocular pressure, but the effect lasted for 4 hours9.


  1. Chien, F.Y., Wang, R.F., and Mittag, T.W. (2003, January). Effect of WIN 55212-2, a Cannabinoid Receptor Agonist, on Aqueous Humor Dynamics in Monkeys. Archives of Ophthalmology, 121(1), 87-90. Retrieved from

  2. Colasanti, B.K., Craig, C.R., and Allara, R.D. (1984, September). Intraocular pressure, ocular toxicity and neurotoxicity after administration of cannabinol or cannabigerol. Experimental Eye Research, 39(3), 251-9. Retrieved from

  3. El-Remessy, A. B., Khalil, I. E., Matragoon, S., Abou-Mohamed, G., Tsai, N.-J., Roon, P., … Liou, G. I. (2003). Neuroprotective Effect of(−)Δ9-Tetrahydrocannabinol and Cannabidiol in N-Methyl-d-Aspartate-Induced Retinal Neurotoxicity : Involvement of Peroxynitrite. The American Journal of Pathology, 163(5), 1997–2008. Retrieved from

  4. Facts About Glaucoma. (n.d.). National Eye Institute. Retrieved from

  5. Glaucoma. (2015, September 15). Mayo Clinic. Retrieved from

  6. Jarvinen, T., Pate, D.W., and Laine, K. (2002, August). Cannabinoids in the treatment of glaucoma. Pharmacology & Therapeutics, 95(2), 203-20. Retrieved from

  7. Merritt, J.C., Crawford, W.J., Alexander, P.C., Andruze, A.L., and Gelbart, S.S. (1980, March). Effect of marihuana on intraocular and blood pressure in glaucoma. Ophthalmology, 87(3), 222-8. Retrieved from

  8. Merritt, J.C., Olsen, J.L., Armstrong, J.R., and McKinnon, S.M. (1981, January). Topical delta 9-tetrahydrocannabinol in hypertensive glaucomas. Journal of Pharmacy and Pharmacology, 33(1), 40-1. Retrieved from

  9. Naveh, N., Weissman, C., Muchtar, S., Benita, S., and Mechoulam, R. (2000, April). A submicron emulsion of HU-211, a synthetic cannabinoid, reduces intraocular pressure in rabbits. Graefe’s Archive for Clinical and Experimental Ophthalmology, 238(4), 334-8. Retrieved from

  10. Nucci, C., Bari, M., Spano, A., Corasaniti, M., Bagetta, G., Maccarrone, M., and Morrone, L.A. (2008). Potential roles of (endo)cannabinoids in the treatment of glaucoma: from intraocular pressure control to neuroprotection. Progress in Brain Research, 173, 451-64. Retrieved from

  11. Pinar-Sueiro, S., Rodriguez-Puertas, R., and Vecino, E. (2011, January). Cannabinoid applications in glaucoma. Archivos de la Sociedad Espanola de Oftalmologia, 86(1), 16-23. Retrieved from

  12. Porcella, A., Maxia, C., Gessa, G.L., and Pani, L. (2001, January). The synthetic cannabinoid WIN55212-2 decreases the intraocular pressure in human glaucoma resistant to conventional therapies. European Journal of Neuroscience, 13(2), 409-12. Retrieved from

  13. Tomida, I., Pertwee, R. G., & Azuara-Blanco, A. (2004). Cannabinoids and glaucoma. The British Journal of Ophthalmology, 88(5), 708–713. Retrieved from

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