One in Six Eye Clinic Patients Used Cannabis Recently, and Nearly Half With Glaucoma Wanted to Try It

What the researchers found

Recent marijuana use (past month): 15.7%. Regular users: 8.2%. Daily users: 4.5%. Among glaucoma patients, 44.2% were interested in using marijuana. Patients who used marijuana less than 24 hours before their exam were significantly more likely to know it lowers IOP (p = 0.02). Beliefs about marijuana effectiveness, IOP lowering, and fewer side effects predicted interest in use.

Why it matters

Cannabis temporarily lowers intraocular pressure, which can mask true readings during eye exams. With 15.7% of patients using recently and many not volunteering this information, ophthalmologists may be making diagnostic and treatment decisions based on falsely low IOP measurements.

The numbers in context

134 patients surveyed. 15.7% recent use (<1 month). 8.2% regular users. 4.5% daily users. 44.2% of glaucoma patients interested in marijuana use. Knowledge that marijuana lowers IOP correlated with use within 24 hours of exam (p = 0.02). Beliefs about effectiveness (p = 0.016), IOP lowering (p = 0.011), and fewer side effects (p = 0.014) predicted interest.

How the study worked

Survey of 134 patients at four University of Minnesota eye clinics during two collection periods (October 2022-January 2023, July-August 2024). Questions covered cannabis use patterns, knowledge of effects on IOP, and attitudes toward marijuana for glaucoma.

What this study cannot tell us

Small convenience sample from one university's clinics limits generalizability. Self-reported cannabis use may be underreported. The survey did not verify IOP measurements against cannabis use timing. Interest in marijuana for glaucoma does not equal actual use.

How to read the evidence

Preliminary: identifies an important clinical issue but small convenience sample from one institution with self-reported data.

When this study was published

2025 study using 2022-2024 survey data.

The bigger picture

The temporary IOP-lowering effect of cannabis creates a diagnostic blind spot. If patients use cannabis before eye exams, their IOP may appear normal when it is actually elevated, potentially leading to missed or delayed glaucoma diagnoses or false reassurance about treatment effectiveness.

Questions still open

• Should eye clinics routinely screen for recent cannabis use before IOP measurement? Would same-day cannabis use lead to clinically significant misclassification of glaucoma risk?

Common questions

Read the original research

An assessment of the prevalence of cannabis use in eye clinic patients and its implications on glaucoma diagnosis and management.

International ophthalmology, 45(1), 484

Citation

Adamek, Andrew J; Hussein, Musse A; Abdulkarim, Iya; Orengo-Nania, Silvia; Sheheitli, Huda. (2025). An assessment of the prevalence of cannabis use in eye clinic patients and its implications on glaucoma diagnosis and management.. International ophthalmology, 45(1), 484. https://doi.org/10.1007/s10792-025-03846-2

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