Fraser Horton
Fraser Horton
Last Updated on September 8, 2022

Using marijuana for recreational purposes is quite common nowadays as it has been for thousands of years. People have been using this plant in religious and spiritual ceremonies, as a way to relax and unwind, and also as medicine for various ailments. Due to more research and studies on the matter, in recent history, medical marijuana has become a viable treatment option for a lot of medical conditions.

Medical marijuana has been known to help treat or ease the symptoms of conditions such as chronic pain, seizures, appetite loss, eating disorders, and many others among which is glaucoma. During the past 50 years, medical cannabis has been used as a treatment option to ameliorate the symptoms or treat glaucoma patients all over the world.

This article will focus on giving you all the important information on the symptoms of glaucoma, the research regarding the use of marijuana to control or treat glaucoma, as well as the potential challenges of using marijuana for treating this medical condition, so read on.

The 411 on Glaucoma

The optic nerve comprises over 1 million nerve fibers responsible for connecting the eye to the brain which is how it transmits electrical impulses to the brain (and that’s essentially how we see). Similar to blood pressure, higher and lower eye pressure can result in eye disease, and glaucoma is one of the conditions which are caused by changes in intraocular pressure. Glaucoma is a medical condition where the optic nerve becomes damaged by fluid buildup in the front part of the eye resulting in increased eye pressure.

The two main types of glaucoma are:

  • Primary open-angle glaucoma;
  • Angle-closure glaucoma. 

The former is the most common type of glaucoma in patients which occurs when fluid buildup causes an increase in the eye pressure over time, while the latter is a condition where the eye drainage becomes completely blocked, causing a rapid increase in the eye pressure.

Glaucoma Symptoms

The symptoms of glaucoma aren’t that many, which is why this condition isn’t noticeable very easily. The most common symptom for this condition is an increased eye pressure, which can only be checked by performing a medical examination by an ophthalmologist, which is why regular eye health screenings are essential for detecting glaucoma before you experience vision loss.

Common risk factors for glaucoma include thin corneas, high blood pressure, diabetes, extreme farsightedness or nearsightedness, to name a few. If you have a family history of glaucoma, it’s even more important to get regular eye checks. 

Generally, the most noticeable symptom when it comes to primary open-angle glaucoma is peripheral vision loss which can happen gradually. However, angle-closure glaucoma has a sudden onset of symptoms including headaches, decreased and blurry vision, nausea, vomiting, eye redness, etc. An angle-closure glaucoma attack can cause permanent optic nerve damage, which is why it’s considered an emergency and must be treated immediately.

Glaucoma and Blindness

Glaucoma is a serious medical condition which if left untreated can lead to blindness. In fact, glaucoma is the top cause of blindness in people over 60. Although it can cause blindness, this isn’t the case for all glaucoma patients, since glaucoma is a condition that can be managed in order to prevent additional vision loss.

Glaucoma Treatment

The only way to prevent vision loss and control and treat glaucoma is by lowering eye pressure. Your ophthalmologist can prescribe eye drops, laser treatments, or incisional surgery, although if you are experiencing an angle-closure glaucoma attack, you may need immediate surgery. According to the American Academy of Ophthalmology (AAO), different patients require different treatment options, depending on the type and severity of glaucoma they have.

Can Medical Marijuana Be Used to Treat Glaucoma?

Using marijuana and cannabis-based products as a treatment option for glaucoma has been researched since the 1970s. The first study done in 1971, looked into how cannabis affects eye pressure by measuring the patient’s eye pressure an hour before and an hour after smoking a marijuana cigarette. The results showed that patients had a 30% decrease in eye pressure after cannabis consumption. This only motivated scientists to further research whether marijuana can be used as a treatment option for glaucoma.

The active ingredient in cannabis, tetrahydrocannabinol (THC), was researched in the 1981 study for its potential use in the treatment of glaucoma. According to the research, THC eye drops didn’t lower intraocular pressure (IOP) since THC isn’t well-absorbed through the eyes.

A 2003 study researched the use of both tetrahydrocannabinol (THC) and cannabidiol (CBD) in the treatment for glaucoma and indicated the potential use of CBD as a topical treatment for glaucoma which formed the basis of further research. A pilot study done in 2006 concluded that a sublingual dose of THC lowered the intraocular pressure for the next 4 hours, while the sublingual dose of cannabidiol (CBD) didn’t lower the intraocular pressure.

According to the research done on this alternative treatment method, marijuana may lower IOP in glaucoma patients, though it isn’t certain whether this can help all glaucoma patients as each case is unique. Regardless of the research done in the field, the National Eye Institute (NEI) still doesn’t advise using marijuana instead of conventional therapies and FDA-approved drugs. Furthermore, marijuana isn’t FDA-approved for the treatment of glaucoma in the states where it’s legal. If you want to check whether weed is legal where you live, check our article on where weed is legal.

The Side Effects of Treating Glaucoma With Marijuana

While the use of marijuana may have neuroprotective effects and lower IOP, there are certain drawbacks to using it as a medical treatment for glaucoma.

According to research, THC is the main cannabinoid that may lower the IOP (CBD doesn’t seem to have the same effects on users), however, it also has mood-altering effects since it’s a psychoactive cannabinoid. And while topical application of THC doesn’t cause psychoactive effects, it isn’t effective in lowering IOP. 

The next problem would be administering the appropriate dosage. Research suggests that cannabis lowers the IOP for a few hours, suggesting that a user would need to consume cannabis a few times a day in order to treat this eye condition, which can be problematic not only for the psychoactive effects but also since some of the other side effects include lowered blood pressure, which essentially means decreased blood flow and a reduced supply of blood to the optic nerves (which might cause additional damage).

Furthermore, the use of marijuana can lead to addiction and marijuana use disorder if patients use the psychoactive cannabinoid on a daily basis. The illegality of medical cannabis in a lot of US states may be an additional problem for patients who want to purchase it as medicine.

Finally, using marijuana as a treatment option for glaucoma may cause some common side effects, such as:

  • Impairment in short-term memory and thinking;
  • Anxiety or paranoia;
  • Decreased reaction time which makes a person unsuitable to drive or operate heavy machinery;
  • Increased heart rate;
  • Coughing, wheezing, and possible lung damage due to smoking marijuana long term.

Final Thoughts on Using Marijuana for Glaucoma

Since optic nerve damage is permanent, it’s essential to maintain the eye pressure stable to prevent vision loss as a result of glaucoma. While cannabis can lower the IOP, ophthalmologists still recommend more standard glaucoma medications for treating this condition since they’ve been extensively researched and tested. The standard therapy doesn’t cause any psychoactive effects, which isn’t the case when using marijuana.

For now, the best option for glaucoma patients is to consult their ophthalmologist and get adequate treatment for glaucoma ranging from eye drops, laser treatment, or incisional surgery. Because glaucoma is a progressive condition which causes vision loss, it may not be the best idea to self-medicate with marijuana in order to treat it. Your best option would be to do an eye exam and consult with your ophthalmologist to find out the best treatment option for your particular case.

Additional Sources

Mack A, Joy J. Marijuana as Medicine? The Science Beyond the Controversy. Washington (DC): National Academies Press (US); 2000. 9, MARIJUANA AND GLAUCOMA. Available from: https://www.ncbi.nlm.nih.gov/books/NBK224386/#

Passani, A., Posarelli, C., Sframeli, A. T., Perciballi, L., Pellegrini, M., Guidi, G., & Figus, M. (2020). Cannabinoids in Glaucoma Patients: The Never-Ending Story. Journal of clinical medicine, 9(12), 3978. https://doi.org/10.3390/jcm9123978

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