Glaucoma and Medical Marijuana
What is glaucoma?
Glaucoma is an eye condition in which abnormally high pressure of the fluid in the eye gradually damages the optic nerve, causing loss of vision. Untreated, glaucoma can eventually lead to blindness.
What causes glaucoma?
Two situations cause interocular pressure (IOP) to build up in the eye:
- The drainage area between the cornea and the iris becomes obstructed and fluid cannot drain out of the eye properly. The blockage may be due to a congenital defect in the angle between the iris and the cornea, or to eye trauma or infection.
- High blood pressure causes the capillaries of the eye to release more fluid than normal into the eyeball.
Glaucoma is one of the leading causes of blindness in the US. Glaucoma is often hereditary and does not appear until later in life, but it can be present at any age, even in newborn babies.
The most common form of glaucoma is often undetected until some damage has already occurred. In its early stages, glaucoma can be detected during a regular eye exam.
How is glaucoma treated?
Vision lost due to glaucoma cannot be recovered, and there is no cure. The treatment for glaucoma involves lowering pressure in the eye with medication, and in some cases, with surgery. Once you are diagnosed with glaucoma, you will need treatment for the rest of your life.
How does medical marijuana help glaucoma?
Research on the ability of marijuana to lower IOP began during the 1970s. At that time it was discovered that marijuana does lower IOP, but the effect wears off after three or four hours, necessitating several doses taken at regular intervals throughout the day. Today’s marijuana products, such as edibles and vaping applications, have longer-lasting effects.
Glaucoma is one of the most common conditions treated with medical marijuana. The structures of the eye have cannabinoid receptors CB1 and CB2, which are activated by THC and other cannabinoids in medical marijuana. It is thought that the compounds in marijuana stimulate microcirculation and reduce inflammation in the eye. Medical marijuana also lowers blood pressure.
Some medications prescribed for treatment of glaucoma have undesirable side effects, and can become less effective over time, while the effect of cannabis remains constant.
- Cannabinoids in the treatment of glaucoma. TomiJärvinen, David WPate, Krista Laine
- Intraocular pressure, ocular toxicity and neurotoxicity after administration of cannabinol or cannabigerol. Colasanti, B.K., Craig, C.R., and Allara, R.D. (1984, September). Experimental Eye Research, 39(3), 251-9.
- Effect of marihuana on intraocular and blood pressure in glaucoma. Ophthalmology, 87(3), 222-8. Merritt, J.C., Crawford, W.J., Alexander, P.C., Andruze, A.L., and Gelbart, S.S. (1980, March).