MPOD (Macular Pigment Optical Density)

Macular pigment is made of three xanthophyll carotenoids —lutein, zeaxanthin and meso-zeaxanthin— that the body cannot synthesize and must obtain from diet (leafy greens, egg yolk, corn). They deposit selectively in the plexiform layers of the fovea, reaching their peak concentration there.

Their dual protective mechanism is well characterized: they absorb phototoxic blue light (peak ~460 nm) before it reaches the photoreceptors, and they quench reactive oxygen species by scavenging singlet oxygen, reducing the chronic oxidative stress of a retina exposed to light and high metabolic demand.

MPOD is measured non-invasively by heterochromatic flicker photometry (HFP) or fundus autofluorescence. Meta-analyses of randomized controlled trials confirm that supplementation with lutein (10-20 mg/day) and zeaxanthin significantly increases MPOD in both healthy individuals and patients with early AMD, with parallel improvements in contrast sensitivity and glare recovery. Because it is reversible and predictive, MPOD serves as a functional biomarker of ocular health and retinal oxidative stress within a healthspan-oriented approach.