# Association between cannabis use and ocular inflammatory disease: a large-scale cohort study

## TL;DR

This study finds that cannabis use is linked to a higher risk of developing serious eye inflammation, especially in the back of the eye.

## Contribution

The study provides the first large-scale evidence linking cannabis use to increased risk of specific inflammatory eye diseases.

## Key findings

- Cannabis users had an 80% higher risk of any uveitis compared to non-users.
- Panuveitis showed the strongest association with cannabis use, with a 264% increased risk.

## Abstract

Cannabis use has increased substantially worldwide, yet its association with inflammatory eye diseases remains poorly understood. This study evaluated whether cannabis users have higher risk of developing uveitis and related inflammatory ocular conditions compared to non-users.

We conducted a retrospective cohort study using the TriNetX Global Collaborative Network database. Adult patients with documented cannabis-related disorders were propensity score-matched 1:1 to patients with no cannabis use, excluding individuals with prior diagnoses that could independently cause uveitis. The primary outcome was the incidence of any uveitis. Secondary outcomes included specific uveitis subtypes, retinal vasculitis, and choroidal degeneration, assessed starting 1 year after cohort entry. Kaplan-Meier survival analysis and Cox proportional hazards models compared outcomes between groups.

After propensity matching, 1,156,655 cannabis users were compared with 1,156,655 matched non-users. Cannabis use was associated with significantly increased risk of any uveitis (hazard ratio [HR] 1.8, 95% confidence interval [CI] 1.65–1.95, p < 0.0001). Specific uveitic conditions showed higher relative risks: panuveitis demonstrated the strongest association (HR 3.64, 95% CI 2.24–5.91, p < 0.0001), followed by choroidal degeneration (HR 3.29, 95% CI 1.74–6.23, p < 0.0001) and retinal vasculitis (HR 3.27, 95% CI 1.81–5.89, p < 0.0001).

Cannabis use was associated with statistically and clinically significant increased risk of ocular inflammatory diseases, particularly those affecting the posterior eye segment. These findings have important implications for ophthalmologic screening and patient counseling as cannabis use becomes more widespread.