Since the late 1970s, there has been a grass-roots effort by the public (and some providers) to advocate marijuana as a form of treatment for IOP reduction.^1,2 Over the years, these efforts have been met with budding social acceptance and use ­— especially in areas where it is legal.³ In fact, one recent survey found that 51% of medical marijuana dispensaries in Colorado recommended marijuana products for the treatment of glaucoma.⁴

As some patients may express an interest in this topic, here’s the quick buzz on research and recommendations to help us be proactive and educated in our patient care.

THC AND CBD

Composed of over 400 compounds, marijuana has two main components which contribute to its physiological effects: ∆-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Specific to the eye, these neurotransmitters work on the ciliary body, trabecular meshwork, and Schlemm’s canal to have a triad effect of decreasing aqueous humor production while at the same time increasing trabecular and uveoscleral outflow.^5-7 Regarding efficacy, some studies have reported that a majority of patients (approximately 60-65%) will have up to a 30% IOP reduction⁸ with about a three- to four-hour duration of action period.⁵

COMPLICATIONS

Interestingly, and because of this shorter duration of action, patients will therefore have to self-treat about six to eight times a day — thus increasing the risk of substance-abuse related addiction and further cost burden on the patient.⁵ In addition to these obvious complications, the perhaps less appreciated side effects can be a real drag, including cardiovascular complications (tachycardia, systemic hypotension), neurologic effects (euphoria, decreased short-term memory, time distortion, insomnia), respiratory damage (emphysema, lung cancer) and ocular effects including conjunctival hyperemia and decreased lacrimation^5-7,9,10 to name just a few.

BUZZ KILL

So, the next time our patient asks for it, should we prescribe marijuana for glaucoma? Consider these responses:

• “No. Traditional therapeutic options offer greater medical benefits and fewer side effects, and thus are still the best alternatives for glaucoma treatment.”¹⁰
• “No. Given that glaucoma is a lifelong disease, commonly requiring treatment for decades, these results strongly suggest that systemic use of THC is not a reasonable treatment option for such patients... Although marijuana can lower the intraocular pressure, its side effects and short duration of action, coupled with a lack of evidence that its use alters the course of glaucoma, preclude recommending this drug in any form for the treatment of glaucoma at the present time.”¹¹
• “No. Alcohol also lowers eye pressure for an hour or so after a drink. Yet no doctor would recommend that you drink alcohol every hour to treat glaucoma. Many other effective treatments are available that don’t have the side-effects….”¹²
• “No. The use of marijuana (in any form) as a medication to reduce eye pressure in glaucoma is not safe or practical. Marijuana also is not a medication that would reduce the risk of developing glaucoma. There are many medications that are FDA-approved to treat eye pressure that have very few side effects and need only be used once or twice daily in the form of an eye drop or pill. Additionally, there are some laser and surgical procedures that can help reduce eye pressure.”¹³

Hopefully with our joint effort, and as responsible providers who continually strive to practice evidenced-based medicine rather than public-based influence, we can better educate our patients and the public on more effective, sustainable treatment options for glaucoma. OM

REFERENCES

1. Green K. Marihuana in Ophthalmology-past, present and future. Ann Ophthalmol. 1979;11(2):203-205.
2. Merritt JC. Glaucoma, hypertension, and marijuana. J Natl Med Assoc. 1982;74(8):715-716.
3. Belyea DA, Alhabshan R, Del Rio-Gonzalez AM, et al. Marijuana Use Among Patients With Glaucoma in a City With Legalized Medical Marijuana Use. JAMA Ophthalmol. 2016;134(3):259-64. doi:10.1001/jamaophthalmol.2015.5209
4. Weldy EW, Stanley J, Koduri VA, et al. Perceptions of Marijuana Use for Glaucoma from Patients, Cannabis Retailers, and Glaucoma Specialists. Ophthalmol Glaucoma. 2020;3(6):453-459. doi:10.1016/j.ogla.2020.06.009
5. Ige M, Liu J. Herbal Medicines in Glaucoma Treatment. Yale J Biol Med. 2020;29;93(2):347-353. Published 2020 Jun 29.
6. Sim RH, Sirasanagandla SR, Das S, Teoh SL. Treatment of Glaucoma with Natural Products and Their Mechanism of Action: An Update. Nutrients. 2022;14(3):534. Published 2022 Jan 26. doi:10.3390/nu14030534
7. Passani A, Posarelli C, Sframeli AT, et al. Cannabinoids in Glaucoma Patients: The Never-Ending Story. J Clin Med. 2020;9(12):3978. Published 2020 Dec 8. doi:10.3390/jcm9123978
8. Green K. Marijuana smoking vs cannabinoids for glaucoma therapy. Arch Ophthalmol. 1998;116(11):1433–1437. doi:10.1001/archopht.116.11.1433
9. Sun X, Xu CS, Chadha N, Chen A, Liu J. Marijuana for Glaucoma: A Recipe for Disaster or Treatment? Yale J Biol Med. 2015;88(3):265-269. Published 2015 Sep 3.
10. Daga FB, Almeida I, Prata TS, Paranhos A Jr. Marijuana for glaucoma treatment: a recipe for disaster. Arq Bras Oftalmol. 2021;84(2):V-VII. doi:10.5935/0004-2749.20210056
11. About Us - American Glaucoma Society (Position Statement on Marijuana and the Treatment of Glaucoma). American Glaucoma Society website. https://www.americanglaucomasociety.net/about/statements. Published Aug. 10, 2009. Accessed Aug. 30, 2022.
12. Does Marijuana Help Treat Glaucoma or Other Eye Conditions? - American Academy of Ophthalmology.American Academy of Ophthalmolgy website. https://www.aao.org/eye-health/tips-prevention/medical-marijuana-glaucoma-treament. Published Mar. 8, 2021. Accessed Aug. 30, 2022.
13. Marijuana as treatment for glaucoma.pdf (aoa.org). American Optometric Association website. https://www.aoa.org/AOA/Documents/Advocacy/position%20statements/Marijuana%20as%20treatment%20for%20glaucoma.pdf.Accessed Aug. 30, 2022