Glaucoma, a group of eye conditions that damage the optic nerve, remains one of the leading causes of irreversible blindness worldwide. Traditionally managed through prescription eye drops and surgeries, recent interest has turned toward alternative therapies, including the use of marijuana. As legalization expands, the potential medical benefits and limitations of cannabis use for glaucoma patients are under increasing scrutiny.
Marijuana and Intraocular Pressure
Glaucoma is most commonly associated with elevated intraocular pressure (IOP), which contributes to progressive optic nerve damage. Since the 1970s, studies have shown that marijuana can temporarily reduce IOP. One of the earliest studies by Hepler and Frank (1971) demonstrated that smoking cannabis lowered IOP in healthy individuals and glaucoma patients by approximately 25%. These results sparked widespread interest in marijuana as a therapeutic option.
However, the reduction in IOP typically lasts only 3 to 4 hours—far shorter than the duration needed for effective, around-the-clock glaucoma control. Continuous dosing to maintain IOP reductions would require patients to consume marijuana six to eight times daily, raising concerns about dependency, cognitive impairment, and potential respiratory harm.
Modern Medical Consensus
While the initial findings are promising, the American Academy of Ophthalmology (AAO) does not recommend marijuana as a primary treatment for glaucoma. In its 2020 statement, the AAO emphasized that although cannabis can lower IOP, its short duration and potential systemic side effects outweigh the benefits when compared to FDA-approved treatments. The Academy instead supports ongoing research into cannabinoid-derived compounds that might offer longer-lasting and safer alternatives.
Emerging Research and Future Directions
Recent studies have explored synthetic cannabinoids and topical applications, such as THC- and CBD-infused eye drops. A 2019 study published in Investigative Ophthalmology & Visual Science found that while THC showed IOP-lowering effects in mice, CBD alone may counteract this benefit. This complexity suggests that cannabinoid therapy must be carefully formulated to be both safe and effective.
Until more robust, long-term clinical trials are conducted, marijuana remains a supplemental option rather than a frontline treatment. Physicians and patients alike are encouraged to discuss the risks and benefits before considering cannabis use for glaucoma.
References:
Hepler, R. S., & Frank, I. R. (1971). Marijuana smoking and intraocular pressure. JAMA, 217(10), 1392–1394. https://doi.org/10.1001/jama.1971.03190100050020
American Academy of Ophthalmology. (2020). Marijuana and Glaucoma: What Ophthalmologists Want You to Know. https://www.aao.org/eye-health/tips-prevention/medical-marijuana-glaucoma-treament
Miller, S., et al. (2019). The effect of cannabinoid compounds on intraocular pressure. Investigative Ophthalmology & Visual Science, 60(1), 258–265. https://doi.org/10.1167/iovs.18-25919
