Department of Human Biology and Movement Sciences, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, 6200 MD, Maastricht, The Netherlands. University Eye Clinic Maastricht, Maastricht University Medical Centre, 6202 AZ, Maastricht, Maastricht, The Netherlands. Department of Human Biology and Movement Sciences, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, 6200 MD, Maastricht, The Netherlands. j.plat@maastrichtuniveristy.nl.