Can smoking marijuana help glaucoma?
While the current political climate could put recent marijuana-legalization laws in peril nationwide, there is still a movement afoot to use marijuana to treat a host of medical conditions, including glaucoma.
Glaucoma is a disease that causes damage to the major nerve of the eye — the optic nerve — a part of the central nervous system that carries visual information from the eye to the brain. The eye experiences a gradual increase of intraocular pressure (IOP) due to an imbalance of the fluid produced in the eye and the amount of fluid drained. Over time, elevated IOP can cause vision loss. (For more about glaucoma, visit our Glaucoma FAQs.)
The National Eye Institute has been studying the idea that marijuana can be helpful in treating glaucoma by lowering IOP since the 1970s. According to the American Academy of Ophthalmology (AAO), research throughout the years has shown that smoking marijuana does lower the IOP of people with glaucoma. However, it only lowers IOP for about three or four hours.
“This short period of time is a major drawback for the use of marijuana as a glaucoma treatment,” AAO found. “Because glaucoma needs to be treated 24 hours a day, you would need to smoke marijuana six to eight times a day around the clock to receive the benefit of a consistently lowered IOP.”
Furthermore, AAO reported in 2014, the risks of smoking marijuana outweigh any benefit. Side effects include an increased heart rate and a decrease in blood pressure, which “raises concerns there could be compromised blood flow to the optic nerve, though no data has been published on the long-term systemic and ocular effects from the use of marijuana by patients with glaucoma.”
The 2014 report concluded that “decreased blood pressure, decreased optic nerve blood flow and short duration of the IOP-lowering effect are significant actual and potential problems with marijuana …” Other adverse effects include conjunctival hyperemia (blood-shot eyes), impaired immune system response, impaired memory for recent events and difficulty concentrating.
In summary, the report found “no significant evidence demonstrating increased benefit and/or diminished risk of marijuana use in the treatment of glaucoma compared with the wide variety of pharmaceutical agents now available.” The report did call for additional studies to see if any of the many active ingredients in marijuana, if purified, could offer an effective treatment for glaucoma and other diseases in the future.