1. Royal Dutch Visio ‐ de Brink Vries The Netherlands
2. Faculty of Behavioural and Social Sciences Department of Pedagogy and Educational Sciences unit of special needs education and youth care University of Groningen Grote Rozenstraat 38 Groningen The Netherlands
3. Research group Healthy AgeingAllied Health Care and NursingHanzehogeschool Groningen Petrus Driessenstraat 3 Groningen The Netherlands
4. Amsterdam UMCVrije Universiteit AmsterdamAmsterdam Public Health research institute Boelelaan 1117 Ophtalmology Amsterdam The Netherlands