Study register / Autonomic / Other / Glaucoma

Glaucoma

4 curated studies · 3 key studies · mechoulam.de

Cannabis is reported to lower intraocular pressure only briefly and to be unsuitable as a glaucoma therapy. A genetic analysis found no causal association between cannabis use and glaucoma.

Rating scheme

The letter rates the quality of a study, independently of its type. Every study type can receive any grade: a review can be B or C when it is small or weak, and an RCT can be S. The grade is a synthesis of study design, journal authority and clinical bindingness:

Highest evidence, large, methodologically first-rate studies or S3 guidelines

Strong evidence, solid, meaningful studies with a clear result

Moderate evidence, smaller or methodologically limited studies

Weak evidence, preliminary, indirect or contradictory findings

Lowest evidence, exploratory hints, single cases or expert opinion

Quality profile per study

To the left of each study there is a profile of four features, it shows the differences within a letter class.

Sample size ★: Number of participants (RCT) or included studies (review).
Blinding: Double-blind, single-blind or open-label.
Effect size: Clear benefit, mixed, no benefit or harm.
Citations / year ★: Age-adjusted citation frequency.

Key studies

01

A

Cannabis use and the risk of primary open-angle glaucoma: a Mendelian randomization study.

Katsimpris et al. ·2023 ·Scientific reports

Read
02

A

Intraocular pressure-lowering effects of tetrahydrocannabinol drugs: a systematic review and meta-analysis.

Dhivagaran et al. ·2026 ·Canadian journal of ophthalmology. Journal canadien d'ophtalmologie

Read
03

B

Single oral administration of dronabinol increases ocular blood flow in patients with glaucoma.

Lindner et al. ·2026 ·Acta ophthalmologica

Read

Systematic Reviews and Meta-Analyses

Syntheses of RCT evidence following Cochrane and PRISMA standards.

Sample size —

Blinding —

Effect size No benefit

Citations / year ★★★★★

● Key study

Katsimpris et al. ·2023 ·Scientific reports

4 citations

Cannabis use and the risk of primary open-angle glaucoma: a Mendelian randomization study.

Design: Meta-Analyse
Sample: n = 216.257 Pat. (gepoolt)

Key finding

Mendelian randomisation analysis shows no evidence of a causal relationship between cannabis use and primary open-angle glaucoma.

Summary

Mendelian randomisation study on cannabis and primary open-angle glaucoma (POAG); n=16.677 cases + 199.580 controls. No causal association between lifetime cannabis use and POAG (OR=1.04, 95% CI 0.88–1.23) or cannabis use disorder and POAG (OR=0.97, 95% CI 0.92–1.03). Sensitivity analyses confirm the null finding.

DOI 10.1038/s41598-023-45872-z ↗

Sample size ★★★★★

Blinding —

Effect size —

Citations / year —

● Key study

Dhivagaran et al. ·2026 ·Canadian journal of ophthalmology. Journal canadien d'ophtalmologie

Intraocular pressure-lowering effects of tetrahydrocannabinol drugs: a systematic review and meta-analysis.

Design: Meta-Analyse
Sample: k = 5 Studien
n = 99 Pat.

Summary

Systematische Review + Meta-Analyse (PROSPERO-registriert) zu THC bei Glaukom/IOD; k=5 Studien, n=99 (69 mit THC-Exposition). Gepoolte IOD-Spitzenreduktion 14.66% (95% CI [3.38%, 25.93%]; p<0.005), IV 33.27% (95% CI [20.36%, 46.17%]; p<0.0001), oral 10.65% und topisch 9.36% (jeweils nicht signifikant). Gegenüber Kontrolle kein signifikanter Unterschied (6.88%, 95% CI [-9.56%, 23.33%]; p=0.41).

DOI 10.1016/j.jcjo.2026.04.003 ↗

Randomised Controlled Trials

Efficacy and safety evidence from controlled interventional trials.

Sample size ★★★★★

Blinding Double-blind

Effect size Clear benefit

Citations / year ★★★★★

Hommer et al. ·2020 ·Clinical pharmacology and therapeutics

14 citations

The Effect of Orally Administered Dronabinol on Optic Nerve Head Blood Flow in Healthy Subjects-A Randomized Clinical Trial.

Design: RCT
Sample: n = 24 Pat.

Key finding

Dronabinol significantly increased optic nerve head blood flow (ONHBF) by 9,5% at rest, while placebo showed no effect.

Summary

n=24 healthy subjects, randomised, placebo-controlled crossover study of 5 mg dronabinol (synthetic THC) oral. Primary finding: dronabinol increased Optic Nerve Head Blood Flow (ONHBF) at rest by 9,5±8,1% vs. baseline (placebo 0,3±7,4%, p<0,001 between study days). No effect on IOP, MAP or Ocular Perfusion Pressure (OPP); no psychoactive side effects. Autoregulatory response of ONHBF to isometric exercise unchanged. Well tolerated; translation to glaucoma patients still pending.

DOI 10.1002/cpt.1797 ↗

Sample size ★★★★★

Blinding Double-blind

Effect size Clear benefit

Citations / year ★★★★★

● Key study

Lindner et al. ·2026 ·Acta ophthalmologica

0 citations

Single oral administration of dronabinol increases ocular blood flow in patients with glaucoma.

Design: RCT
Sample: n = 23 Pat.

Key finding

A single dose of 10 mg dronabinol significantly increased optic nerve head blood flow by approximately 10-12% without effects on intraocular pressure or blood pressure.

Summary

n=23 patients with primary open-angle glaucoma (POAG), randomized double-blind cross-over dronabinol (5 mg vs. 10 mg) vs. placebo. 10 mg dronabinol significantly increased optic nerve head blood flow (ONHBF) (MA +10.8±20.6%, p=0.018; MV +12.0±24.8%, p=0.042; MT +11.0±22.6%, p=0.022 vs. placebo) up to 4 h post-administration, without affecting IOP or blood pressure (p>0.548). Vessel density in the superficial vascular plexus +6.7±14.7% (p=0.040 vs. 5 mg).

DOI 10.1111/aos.17573 ↗