Metformin to protect the optic nerve in glaucoma
Official title: Metformin as a Neuroprotective Therapy for Glaucoma - A Randomized Controlled Trial
Run by The University of Hong Kong · NCT05426044 · Data updated 2026-11-12
This trial will test whether taking metformin twice daily helps slow optic nerve thinning and vision loss in adults with primary open‑angle glaucoma who are still progressing despite controlled eye pressure.
Quick facts
| Phase | Phase 2 |
|---|---|
| Study type | Interventional |
| Ages | 18 Years and up |
| Sex | All |
| Enrollment | 125 (estimated) |
| Sponsor | The University of Hong Kong Academic / other |
| Locations | 1 site (Wong Chuk Hang) |
| Status | Recruiting |
| Started | June 1, 2025 |
| Main results expected | December 31, 2027 |
| Study ends | December 31, 2027 |
| Registry record updated | November 20, 2025 |
| Trial ID | NCT05426044 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Adults (≥18) with primary open‑angle glaucoma, best corrected visual acuity ≥20/40, IOP ≤24 mmHg, and documented progressive RNFL or GCIPL thinning on OCT over the past three years who do not have diabetes, kidney or liver disease are ideal candidates.
✕Probably not a fit
Patients with diabetes, kidney or liver disease, pathological myopia, other optic nerve or retinal disorders, cognitive impairment, or those unable to produce reliable OCT or visual field tests are excluded and unlikely to benefit from this trial.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This is a randomized, double‑blind, placebo‑controlled Phase 2 trial enrolling about 125 adults with primary open‑angle glaucoma who show progressive RNFL or GCIPL thinning. Participants are randomly assigned 1:1 to oral metformin 750 mg twice daily (1500 mg/day) or matching placebo, with investigators and patients blinded to assignment. Clinical exams include Goldmann applanation tonometry, OCT RNFL/GCIPL imaging, and visual field testing at screening, baseline, and follow‑up visits, with all procedures performed at the HKU Eye Centre. The trial excludes patients with diabetes, significant kidney or liver disease, pathological myopia, or other eye/neurologic conditions that could confound measurements.
Why it matters
Potential benefit: If successful, metformin could slow optic nerve degeneration and reduce vision loss in glaucoma patients independent of lowering intraocular pressure.
How similar studies have gone: Observational and preclinical data suggest metformin may reduce risk of age‑related neurodegenerative disease and glaucoma progression, but randomized clinical evidence for neuroprotection in glaucoma is limited and this approach remains relatively novel.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * age ≥18 years * best corrected VA ≥20/40 * IOP ≤24mmHg at the screening and baseline visits * progressive RNFL and/or GCIPL thinning by TPA or GPA over the past 3 years in at least one eye. Exclusion Criteria: * patients with DM, kidney or liver diseases * pathological myopia * cognitive impairment (e.g. Alzheimer's disease) * diseases that may cause visual field loss or optic disc abnormalities other than glaucoma * inability to perform reliable visual field * suboptimal quality of OCT images. Both eyes of a patient will be included in the analysis if both eyesare eligible for inclusion.
Where it's running
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HKU Eye Centre
Wong Chuk Hang, Hong Kong Recruiting
Study contacts
- Principal investigator: Christopher LEUNG, MD — The University of Hong Kong
- Study coordinator: Christopher LEUNG, MD
- Email: cleung21@hku.hk
- Phone: (852)3962-1405
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.