Nutritional Supplementation for Myopia Prevention and Control: A Systematic Review of Randomized Controlled Trials.

Nine RCTs met eligibility criteria for inclusion in this systematic review of nutritional supplementation for myopia prevention and control.

• Databases searched included PubMed, Web of Science, and Scopus up to 5 August 2025.
• Eligible studies were RCTs involving individuals with myopia or at risk of myopia, comparing nutritional supplementation with placebo or active controls.
• The review was registered in PROSPERO (CRD420251149727) and conducted in accordance with PRISMA 2020 and AMSTAR-2 guidelines.
• Two reviewers independently screened studies, extracted data, and assessed risk of bias using the Cochrane RoB 2 tool.

Carotenoids including crocetin, lutein, zeaxanthin, and astaxanthin produced modest benefits in visual outcomes.

• Benefits observed included improved macular pigment optical density (MPOD) and reduced visual fatigue.
• In one pediatric trial, carotenoid supplementation was associated with slightly less axial elongation.
• No consistent clinically meaningful reduction in myopia progression was observed across carotenoid trials.

Anthocyanin-rich extracts improved mesopic contrast sensitivity and subjective asthenopia in included trials.

• Anthocyanins were among the nutritional categories evaluated alongside carotenoids, polyunsaturated fatty acids, and combined nutraceutical formulations.
• Improvements were noted specifically for mesopic contrast sensitivity and subjective symptoms of asthenopia.
• No consistent clinically meaningful reduction in myopia progression was observed with anthocyanin supplementation.

A combined carotenoid-polyphenol formulation enhanced accommodative facility in included participants.

• This finding was reported among outcomes related to visual function, one of the review's primary outcome categories.
• Accommodative facility was assessed as part of the broader visual function outcomes alongside refractive outcomes, axial length, MPOD, and visual fatigue symptoms.
• Despite improvements in accommodative facility, no consistent clinically meaningful reduction in myopia progression was demonstrated.

No consistent clinically meaningful reduction in myopia progression was observed across any nutritional supplementation category.

• Trials were generally small, heterogeneous, and short in duration.
• Outcome measures assessed included refractive outcomes, axial length, macular pigment optical density (MPOD), visual function, and symptoms of visual fatigue.
• Proposed mechanisms for supplementation effects included antioxidative, anti-inflammatory, and extracellular matrix-regulating pathways.
• The review concluded that nutritional supplementation may improve visual function and retinal antioxidant status but lacks strong evidence for slowing myopia progression.

The included trials were characterized by small sample sizes, heterogeneity, and short duration, limiting the strength of conclusions.

• Risk of bias was assessed using the Cochrane RoB 2 tool.
• Heterogeneity was noted across trials in terms of populations, interventions, and outcome measures.
• The authors concluded that larger, long-term RCTs are needed before recommending supplementation for routine myopia management.