Glaucoma & Medical Marijuana

Written by Emery Feldman, PharmD
Edited by Markita Wilburn, PharmD

It's for my glaucoma! A statement we have heard countless times in film and television when a character is confronted about their marijuana use. But what is Glaucoma? Why has it become associated with marijuana, and more importantly, what is the role, if any, marijuana plays in the treatment of it?

What is Glaucoma?

Glaucoma is a variation of eye diseases that can lead to vision loss and potentially total blindness if left untreated. There are several forms of glaucoma, but the most common is called open-angle glaucoma. In open-angle glaucoma, the drainage system for ocular fluid is defective, resulting in an increase in pressure that, over time, can cause damage to the optic nerve. The longer glaucoma goes without medical treatment, the more damage it causes to the optic nerve, and the gradual loss of eyesight then occurs. Though the progression of glaucoma can be prevented, early detection and adequate treatments are necessary to maintain proper eye health and function.     

 

Treatment

All forms of glaucoma treatment aim to lower intraocular pressure to prevent further optic nerve degeneration. Commonly accepted options include laser therapy, surgery, and prescription medications. Prostaglandins (latanoprost, travoprost), beta-blockers (timolol), alpha-adrenergic agonists (brimonidine), and carbonic anhydrase inhibitors (dorzolamide) are types of pharmaceutical eye drops commonly prescribed to treat glaucoma, which all aim to decrease the amount of pressure in the eye. Prostaglandins like Xalatan (latanoprost) help by increasing the amount of fluid that drains from the eye to lower intraocular pressure, while the others work by decreasing the amount of fluid your eye makes. If used as prescribed, these medications can maintain normal pressure within the eye and prevent disease progression.

 

MMJ & Glaucoma

In the early 1970s, a study suggested that marijuana could be a possible treatment for patients suffering from glaucoma. While the research at the time was limited, the notion of using marijuana and THC for the condition stuck in the minds of the public. As of now, marijuana is not a recommended treatment for glaucoma. Although marijuana and cannabinoids have been shown to reduce intraocular pressure, the use of marijuana has several notable limitations. The first is its short duration of action, with inhaled formulations lowering intraocular pressure for approximately 2 hours and ingested forms for up to 4 to 6 hours. The short-acting benefit of marijuana requires frequent dosing compared to other standard medications that can reduce intraocular pressure for 12 to 24 hours with each dose. The second drawback of its use is the euphoria or “high” associated with larger doses of THC, which, to some, may be an unpleasant experience. For this, many patients may not find these effects ideal to consistently manage symptoms of glaucoma.

 

Although no studies have proven medical marijuana lowers intraocular pressure safely and effectively better than medications prescribed by an eye doctor, THC has been shown to cause up to 25 to 30 percent reduction via CB1 and GRP-18 receptor activation.

CBD, on the other hand, has been shown to increase intraocular pressure by decreasing the affinity of THC at the receptor site in both animal and human studies. These studies showed that the addition of CBD to THC blocked the decrease in intraocular pressure caused by THC at a dose of 40mg CBD and advised to avoid use in glaucoma patients.

Both THC and CBD have neuroprotective properties, and some studies have shown these effects to protect the retina in glaucoma models. According to an article published in Glaucoma Today, patients of the PA MMJ program who use medical marijuana to reduce intraocular pressure would be best to seek a THC-dominant preparation. Those with stable intraocular pressure who wish to protect the retina may benefit from a combination of THC and CBD.

It is best to talk to your physicians about whether medical marijuana therapy is safe to manage the symptoms of your qualifying condition. If you are looking for more information about including medical marijuana in your treatment plan, we welcome you to contact us for a consultation with a Maitri Pharmacist or visit your closet dispensary for an in-person experience.

  

TIPS 

  • Early detection — schedule and commit to annual eye exams.  

  • Wear protective U.V. ray lenses daily — no exception.

  • Use a drop-aid device to ensure that eye drops are placed efficiently in the eye(s). 

  • Know the signs of Hypotension — persistently low blood pressure may exacerbate disease progression. 

  • Avoid taking blood pressure-lowering medications in the evening before bedtime — lower nocturnal blood pressures may increase the risk of glaucoma progression.

  • Tell your ophthalmologist if you medicate with MMJ.

  • For eye drop tips, visit - https://www.glaucoma.org/treatment/eyedrop-tips.php

 

References

Glaucoma - Symptoms and causes. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/glaucoma/symptoms-causes/syc-20372839#:~:text=Open-angle%20glaucoma%20This%20is%20the%20most%20common%20form

Katarina. Is Marijuana a Treatment for Glaucoma? Ophthalmology & Visual Sciences. Published August 28, 2023. Accessed January 16, 2024. https://ophthalmology.wustl.edu/is-marijuana-a-treatment-for-glaucoma/

Lopez MJ, Nataneli N. Cannabis Use For Glaucoma And Associated Pain. PubMed. Published 2022. https://www.ncbi.nlm.nih.gov/books/NBK572112/

Mack A, Joy J. MARIJUANA and GLAUCOMA. National Academies Press (US); 2000. https://www.ncbi.nlm.nih.gov/books/NBK224386/

Turbert D. Does Marijuana Help Treat Glaucoma or Other Eye Conditions? American Academy of Ophthalmology. Published February 7, 2019. https://www.aao.org/eye-health/tips-prevention/medical-marijuana-glaucoma-treament

Aref, Ahmad. Cannabis and Glaucoma: The importance of strain and chemical composition. Glaucoma Today. Therapeutics Update July/August 2020. https://glaucomatoday.com/articles/2020-july-aug/cannabis-and-glaucoma

Miller S, Daily L, Leishman E, Bradshaw H, Straiker A. Δ9-Tetrahydrocannabinol and Cannabidiol Differentially Regulate Intraocular Pressure. Invest Ophthalmol Vis Sci. 2018 Dec 3;59(15):5904-5911. doi: 10.1167/iovs.18-24838. PMID: 30550613; PMCID: PMC6295937.

Yazulla S. Endocannabinoids in the retina: from marijuana to neuroprotection. Progress in retinal and eye research. 2008 Sep 1;27(5):501-26

UpToDate. Uptodate.com. Published 2019. https://www.uptodate.com/contents/open-angle-glaucoma-treatment

 

Marisa maraugha