The impact of nutrition on glaucoma progression: evidence from systematic literature review and meta‑analysis

Topic This systematic review and meta-analysis aims to determine if nutritional interventions have an impact on glaucoma progression. The clinical question being answered is whether nutritional supplementation compared to baseline values has an impact on measures of glaucoma progression, i.e., intraocular pressure (IOP), visual field mean deviation (MD), pattern standard deviation (PSD), and retinal nerve fiber layer (RNFL) thickness. Clinical relevance Glaucoma is a chronic neurodegenerative optic neuropathy and is a major cause of irreversible blindness worldwide. The conventional treatment for glaucoma is to reduce IOP to slow the progression of glaucoma. However, progression of glaucoma is seen in patients with well-controlled IOP levels, suggesting that there is a need to look for additional therapeutic options, including nutritional factors, antioxidants, omega-3 fatty acids, vitamins, and nutraceuticals. Methods A comprehensive search of the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, PubMed Central (PMC), and Google Scholar was undertaken from date of inception to 6 March, 2026. Randomized controlled trials (RCTs) and observational studies evaluating the diet, nutritional status, or nutritional supplementation in adults with glaucoma and reporting outcomes on the progression of the disease were considered for inclusion. Risk of bias in the included studies was assessed with the revised Cochrane Risk of Bias tool (RoB 2) for RCTs and the Newcastle–Ottawa Scale for cohort studies. Results Qualitative synthesis included 21 studies with 1,209 participants, and 11 studies were available for meta-analysis. Antioxidants, omega-3 fatty acids, vitamins, and neuroprotective agents such as coenzyme Q10, ginkgo biloba extract, citicoline, and palmitoylethanolamide were included. Meta-analysis found no statistically significant change at six months in IOP (mean difference − 2.42 mmHg, 95% CI − 7.53 to 2.70), MD (2.23 dB, 95% CI − 1.04 to 5.50), or RNFL thickness (− 16.00 µm, 95% CI − 70.77 to 38.76), although there was a significant decrease in PSD (− 0.33 dB, 95% CI − 0.47 to − 0.19). Conclusion The current evidence suggests that nutritional interventions do not significantly affect major indicators of glaucoma progression in the short term; the small PSD reduction, based on three cohort studies, should not be interpreted as a clinically meaningful neuroprotective effect. Given the low-to-moderate certainty of the underlying evidence, nutritional supplements may be considered as a potential adjunct to conventional treatment, though evidence supporting their routine clinical use remains insufficient; the long-term effects of nutritional supplements on glaucoma need to be determined through large, long-term RCTs.