Lutein is made using a special process that removes the natural lutein pigment from the delicate petals of marigold flowers (Tagetes erecta), the only source of plant lutein approved by FSANZ.
Lutein accumulates in the brain and eye, where it protects the delicate cell membranes:
In children, the eyes collect lutein and other carotenoids from breast milk, milk formulas and foods. Most of it accumulates in the macula, part of the sensitive retina, which is responsible for the kind of detailed, close-up vision that develops during reading and writing .
In one study, improvements were observed in low-light visual sensitivity in infants . As children get older, their macula makes more of a substance called “macular pigment”, a blue light filter.
It has been found that macular pigment increases as toddlers get older, but also, the level of lutein and combined carotenoids in their blood corresponds to the level of macular pigments  (figures).
Increase in macular pigments in children vs age
Relationship between lutein levels and macular pigments in children