Green leafy vegetables may help improve visual processing because they contain carotenoid compounds, including lutein and zeaxanthin, which are important to eye health. Young, healthy men and women were enrolled in a study where they were randomly assigned to 3 groups: the first group received placebo, the second received zeaxanthin only and the third group received a mix of lutein, zeaxanthin and omega-3s. In both the group receiving zeaxanthin and the group receiving the combination supplement, researchers observed that visual acuity increased 12% while visual motor reaction time increased by 10%. Researchers say that supplementation resulted in significant improvements in visual processing speed.