What does the yellow colour of autumn leaves have to do with better sight in old age?
They are called xanthophylls, or more precisely, nitrogen-free carotenoids. When ingested, their pigment, lutein, is concentrated in the macula, the region of sharpest vision in the eye, or the area with the highest density of light and colour-sensitive rods and cones.
An adequate presence of lutein decreases the risk of macular degeneration. Nature offers versatile solutions to all living things thereby demonstrating a symbiotic relationship of astonishing intensity and value.