Canadian researchers from the Food Research Program, Agriculture and Agri-Food Canada evaluated several primitive and modern wheat species, and found the highest levels of carotenoids including lutein, zeaxanthin and beta-carotene in Einkorn. Durum, Kamut® and Khorosan had intermediate levels, while common bread or pastry wheat had the lowest levels of carotenoids.  The carotenoids studied are thought to be important to eye health, among other functions.
Journal of Agricultural and Food Chemistry, February 2007; 55(3): 787-94