1. Amsterdam University Medical Centers, Vrije Universiteit; Department of Ophthalmology, Amsterdam Public Health research institute; Amsterdam Netherlands
2. University of Florence; Department of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA); Largo Palagi, 1 Florence Italy 50134
3. Netherlands institute for health services, NIVEL research; P.O. Box 1568 Utrecht Netherlands 3500 BN
4. Radboud University Medical Center; Department of Ophthalmology; Nijmegen Netherlands
5. Elkerliek Hospital; Department of Ophthalmology; Helmond Netherlands