1 Erasmus University Medical Centre, Rotterdam, the Netherlands; The Generation R Study Group, Erasmus University Medical Centre, Rotterdam, the Netherlands.
2 Erasmus University Medical Centre, Rotterdam, the Netherlands; Radboud University Medical Centre, Nijmegen, Gelderland, the Netherlands; Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland. Electronic address: c.c.w.klaver@erasmusmc.nl.