This study aims to determine whether a combination of vitamins (B6, B9, B12, and choline) can help protect the eyes of people with glaucoma and slow vision loss. The study will assess whether these vitamins support retinal cells and maintain or improve their function.

Adults aged 18 and older with primary open-angle glaucoma (including normal-tension glaucoma) or pseudoexfoliation glaucoma, and those with mild to moderate glaucoma, may be eligible. Participants must meet specific medical criteria and cannot take additional vitamin supplements during the study.

Participants will be randomly assigned to one of two groups: one group will take a daily vitamin supplement (B6, B9, B12, and choline) for one year, along with standard glaucoma care, while the other will continue standard care without extra vitamins. The vitamins used are well tolerated at selected doses, with possible mild side effects such as an upset stomach or tingling sensations. They will visit the clinic five times over 12 months (at the start, and at 3, 6, 9, and 12 months) for routine eye tests, including measuring eye pressure, checking vision and visual fields, taking scans of the eye's nerve layers (OCT), and completing an electroretinogram (ERG) to assess retinal function. Blood samples will also be collected.

If the vitamins are effective, this could provide an additional strategy alongside current eye pressure lowering treatments to reduce vision loss.

Eligibility Criteria

Inclusion Criteria:

Patients with the following characteristics will be eligible for inclusion in the trial:

• 18 years or older at the time of inclusion
• Diagnosis of Primary Open-Angle Glaucoma (POAG), Normal Tension-Glaucoma (NTG) or Pseudoexfoliation Glaucoma (PEXG) in one or both eyes diagnosticed by an ophthalmologist.
• Best corrected Snellen VA of 0.3 or better in the study eye(s)
• Two or more reliable VF tests with less than 15% false positives

Exclusion Criteria:

Patients who meet any of the following criteria will be excluded from participation in the study:

• Visual field damage worse than -16dB in the study eye(s)
• Eye pressure greater than 35 mmHg in study eye(s) on either of two measurement occasions or a mean pressure of 30 mmHg over two occasions
• Any disease affecting retinal function
• Neurological or other non-glaucomatous conditions that may affect the visual field
• Inability to perform visual field examination
• Unwillingness to stop any intake of multivitamins or B vitamin substances
• Known allergy or intolerance to B-vitamins
• Previous eye surgery, except for uncomplicated cataract surgery
• Pregnant or breastfeeding women
• Women of childbearing potential who do not use reliable contraception
• Any disease or condition likely to prevent long-term follow-up
• Cancer diagnosis within the last 5 years (except treated squamous cell carcinoma)
• History of liver disease or stomach ulcers
• Inability to understand and speak Swedish or English

We aim to share pseudonymized individual participant data that underlie results in a publication in accordance with institutional regulations.