With the legalization of marijuana for medical use in Illinois in 2013 and broader legalization in 2020, many of our patients have asked whether it might be beneficial for eye health—particularly in managing glaucoma. As eye care professionals, we want to clarify what is known and unknown about marijuana in this context.
Understanding Glaucoma
Glaucoma refers to a group of eye diseases that damage the optic nerve, often leading to progressive, irreversible vision loss. The most significant risk factor for developing and worsening glaucoma is an increase in intraocular pressure (IOP). It has been well-established that lowering IOP helps prevent the onset of glaucoma and slows its progression.
Traditional glaucoma treatments include:
- Medications (Eye Drops): Commonly used as the first line of defense to reduce IOP.
- Laser Therapy: Procedures like selective laser trabeculoplasty (SLT) help fluid drain more effectively from the eye.
- Surgery: Recommended if drops or laser therapy are insufficient or if the patient experiences extreme side effects.
While oral medications were once a more significant part of long-term glaucoma management, many have been replaced by newer, better-tolerated treatments like eye drops.
The Marijuana Question
Marijuana has been shown to lower IOP in both healthy individuals and those with glaucoma. However, there are a few key points to note:
- Short Duration
Marijuana’s IOP-lowering effect lasts only three to four hours. To maintain 24-hour eye pressure control, a person would need to use marijuana approximately every three hours—a schedule that most people find neither practical nor desirable. - Side Effects
- Psychoactive Effects: Marijuana can impair judgment and reaction times, making it unsafe for driving or operating machinery.
- Respiratory Concerns: Smoking marijuana regularly can damage the lungs, especially when used over a long period.
- Systemic Side Effects: Oral or sublingual forms of THC avoid lung damage but may still cause issues like low blood pressure or cognitive changes. Patients in some studies discontinued using THC due to these side effects within months.
- Incomplete Long-Term Data
Lowering IOP is just one factor in managing glaucoma. Researchers also believe maintaining good blood flow to the optic nerve is critical. Marijuana can lower blood pressure, which might reduce blood supply to the optic nerve and potentially negate any benefits of lowering IOP. Long-term, large-scale studies are needed to determine if marijuana can effectively and safely preserve vision over time.
Potential for Neuroprotection?
On a more promising note, scientists have discovered cannabinoid receptors in eye tissues, suggesting that targeted, local administration of marijuana-like compounds might one day be useful. Some evidence indicates cannabinoids could offer neuroprotective benefits to cells in the optic nerve. This raises the possibility that a well-tolerated, long-acting formulation could both lower IOP and protect nerve tissue.
However, until research produces a reliable, safe treatment that undergoes rigorous clinical testing—demonstrating real benefits in halting glaucoma progression—there is no scientific basis to recommend marijuana or related compounds for routine glaucoma therapy.
Our Recommendation
Based on current evidence, Illinois Eye Center does not recommend the use of marijuana as a primary treatment for glaucoma. Established therapies—prescription eye drops, laser treatments, and surgeries—have decades of proven safety and efficacy behind them. If you’re considering alternative treatments, including marijuana, we encourage you to discuss the risks and benefits with your Illinois Eye Center ophthalmologist. Our priority is helping you find the safest, most effective approach to preserving your vision. To discuss, request an appointment here.
It is important to note that this post reflects the Illinois Eye Center’s interpretation of existing research and experience. For individual advice and treatment, please consult your Illinois Eye Center doctor.