Vishwanathan R, Iannaccone A, Scott TM, Kritchevsky SB, Jennings BJ, Carboni G, Forma G, Satterfield S, Harris T, Johnson KC, Schalch W, Renzi LM, Rosano C, Johnson EJ. Macular pigment optical density is related to cognitive function in older people. Age Ageing. 2014 Mar; 43(2):271-5.