From Supplements to Sight: Quantifying the Impact of Lutein and Carotenoid on Age‐Related Macular Degeneration—A Systematic Review and Meta‐Analysis of Randomized Controlled Trials

Purpose To quantify the effects of lutein‐containing supplementation on structural and functional visual outcomes in patients with age‐related macular degeneration (AMD), with particular focus on disease stage and treatment exposure. Methods A meta‐analysis of randomized, placebo‐controlled trials was conducted. Nine RCTs involving 860 participants were included. Eligible studies evaluated oral lutein alone or in combination with zeaxanthin or epilutein and reported pre‐ and post‐treatment measurements of macular pigment optical density (MPOD) and best‐corrected visual acuity (BCVA). Random‐effects models were applied to calculate pooled effect sizes using Hedges’ g. Subgroup and meta‐regression analyses were performed to explore stage‐specific responses and dose‐duration associations. Results Across the 9 RCTs, lutein‐containing supplementation significantly improved MPOD (Hedges’ g = −0.589, p < 0.001) and BCVA (Hedges’ g = −0.827, p = 0.001). Improvements were predominantly observed in early‐stage AMD, whereas no statistically significant benefit was detected in late‐stage disease. Lutein monotherapy demonstrated greater visual benefit than combination regimens. Meta‐regression analyses revealed significant positive associations between treatment effect and both supplementation duration and total lutein exposure. Contrast sensitivity and serum lutein concentrations also improved significantly. Conclusion Lutein‐based supplementation is associated with measurable structural and functional visual benefits in early‐stage AMD. Treatment effects appear dose‐ and duration‐dependent, while evidence in late‐stage AMD remains limited. These findings support early intervention strategies and warrant further investigation into long‐term therapeutic impact.