What is Marijuana?
Over the years there has been considerable discussion on the potential medical uses of marijuana. Delta-9-tetrahyrocannabinol (THC) is the principal psychoactive component of marijuana. It is important to know that marijuana is composed of a mixture of dried flowering pieces and leaves from the plant cannabis sativa. It consists of more than 400 chemicals of which the major chemical group is cannabinoids. Marijuana is listed as a Schedule I drug.
What is Glaucoma?
Glaucoma is one of the leading causes of permanent blindness in the United States and is the leading cause of blindness in African-Americans. Approximately three million people have glaucoma. It is a multifactorial disease process but the dominant factor is intraocular pressure that damages the optic nerve in back of the eye. The treatment for glaucoma is to lower the eye pressure to a point that the optic nerve is no longer damaged.
How Does Marijuana Work to Lower Eye Pressure?
The exact mechanism of action of lowering the eye pressure is not known. CB1 receptors have been discovered in the eye which may be the method of action. It is felt that marijuana may increase the outflow of fluid from the eye. It does not appear to lower eye pressure used topically with eye drops but works better when smoked and somewhat to a lesser extent when ingested.
Marijuana Use in Glaucoma Patients
Marijuana when smoked lowered the eye pressure by approximately 25% normal controls and patients with glaucoma. The duration of the pressure lowering effect is 3 to 4 hours. Marijuana would have to be used several times per day and through the night in order to control the eye pressure in a patient with glaucoma.
Other Associated Effects of Smoking Marijuana
Causes the heart rate to increase significantly
Drop in blood pressure systolic and diastolic
Conjunctival hyperemia (red eyes)
Impaired immune system
Increased risk of cancer
Poor pregnancy outcomes