A study on the impact of diet on age-related macular degeneration (AMD) found that those who took the highest amounts of carotenoids, such as lutein and zeaxanthin, had a 43% lower risk of age-related macular degeneration than those who took the least amounts.
Seddon, Johanna M., Umed A. Ajani, Robert D. Sperduto, Rita Hiller, Norman Blair, Thomas C. Burton, Marilyn D. Farber, Evangelos S. Gragoudas, Julia Haller, Dayton D. Miller, et al. Dietary Carotenoids, Vitamins A, C, and E, and Advanced Age-Related Macular Degeneration. JAMA. 1994; 272(18): 1413-20. http://jama.ama-assn.org/cgi/content/abstract/272/18/1413