Side effects of zeaxanthin include yellowing of the skin when taken in excess, according to Web MD. However, the antioxidant is widely considered safe; 2 mg daily are recommended for good eye health by the American Optometric Association.
Along with lutein, the potent antioxident is found in many vegetables and occurs in high concentrations in the human eye. High levels of zeaxanthin within eye tissue are linked to better vision, especially in dark conditions and in the presence of glare, according to Web MD. Appropriate amounts of zeaxanthin and lutein are obtained from spinach, kale, collard greens, turnips, corn and broccoli.