To clarify inconsistencies in literature on the effects of Lutein on eye health, Feng et. al reviewed nine randomized clinical trials on a total of 920 eyes, of which 855 had age-related macular degeneration (AMD) for this meta-analysis. Lutein supplementation was shown to have increases in MPOD (macular pigment optical density), visual acuity and contrast sensitivity. Studies also suggested higher doses of Lutein (10 mg vs 20 mg/day) for longer treatments (> 6 months) have benefits for AMD
References:
Feng, L., Nie, K., Jiang, H., & Fan, W. (2019). Effects of lutein supplementation in age-related macular degeneration. PloS One, 14(12), e0227048. https://doi.org/10.1371/journal.pone.0227048