A plant pigment the body cannot make but deposits in the centre of the retina and in brain tissue. Supplementation reliably raises retinal pigment, shortens recovery from glare and improves vision in eyes that already have disease. Memory, lens and heart findings appear only in people starting from low intake. The safety record is unusually clean. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Serum lutein + zeaxanthin | 0.6–1.2 µmol/L | Confirms the dose is actually absorbed |
| Macular pigment optical density (MPOD) | ≥0.50 density units at 0.5° eccentricity | The tissue-level target the supplement is meant to move |
| Contrast sensitivity (Pelli-Robson chart) | ≥1.65 log units | The functional endpoint that matters day to day |
| Skin carotenoid score (reflection spectroscopy) | ≥400 on the 0–800 scale | A cheap proxy for whole-body carotenoid status |
| Retinal structure on OCT and dilated examination | No established numeric target — track drusen count and geographic atrophy area against the individual's own baseline scan | Detects progression that supplementation is meant to slow |
| HDL-C on a lipid panel | >60 mg/dL | The one blood lipid a lutein trial has moved |
Cadence: Baseline set before starting; serum lutein at 8–12 weeks, macular pigment at 6 months then annually, contrast sensitivity annually, retinal examination every 12 months — every 6 months with intermediate macular degeneration. Serum repeated at 3 months on orlistat, ezetimibe or a bile-acid sequestrant.