What is glaucoma?

Glaucoma is a chronic eye disease caused by damage to the optic nerve. The optic nerve is the cable that goes from the brain to the eye and allows us to see light and shapes. One of the major risks for glaucoma is high pressure in the eye, but it can also occur with normal pressure. Uncontrolled eye pressure can cause damage to the optic nerve, and it increases the chance of vision loss.

Is it legal to treat glaucoma with marijuana or CBD?

To date, 34 states and the District of Columbia have legalized marijuana for medical use. With all the information on marijuana’s health benefits online and in the news, it is hard to know what to believe.

Why do some think that marijuana or CBD could be a treatment for glaucoma?

Science has shown that marijuana can lower the pressure inside the eye for a short period of time without using eye drops. This happens because there are THC (the active ingredient in marijuana) receptors in the drainage channels of the eye. This helps the channels to open, allowing for fluid to leave the eye and lower the pressure. A popular marijuana alternative, CBD, has been shown to deprive the eye of oxygen and nutrients, worsening glaucoma in experiments.

If marijuana lowers eye pressure, why is it not a widely accepted treatment?

Although smoking marijuana can lower pressure in the eye, it only lasts for about 3 to 4 hours during intoxication. Therefore, marijuana would need to be used 6 to 8 times a day around the clock to keep eye pressure low. Also, there are many known side effects of long-term marijuana use, such as elevated heart rate, low blood pressure, and balance issues. Smoking marijuana can cause lung disease and increase chances for lung cancer. There is also little information about marijuana’s effect on other medicines, potential to cause other cancers, and safety in pregnancy. 

What can I do for treatment and where should I get information?

Be sure to discuss treatment options with your ophthalmologist. Current medical evidence does not support the use of marijuana to treat glaucoma. In the future, there may be a role for medical marijuana in glaucoma treatment, but not at this time. The American Academy of Ophthalmology (www.aao.org ) and the American Glaucoma Society (www.americanglaucomasociety.net ) are sources for more patient information.

Editor’s note: This handout is courtesy and copyright of the authors.