1. Institute of Clinical Medicine, Faculty of Medicine University of Oslo Oslo Norway
2. Department of Medical Biochemistry Oslo University Hospital Oslo Norway
3. Department of Plastic and Reconstructive Surgery Oslo University Hospital Oslo Norway
4. Department of Ophthalmology, University of Groningen University Medical Center Groningen Groningen The Netherlands
5. Schepens Eye Research Institute of Massachusetts Eye and Ear Harvard Medical School Boston Massachusetts USA
6. Department of Twin Research & Genetic Epidemiology King's College London St Thomas' Hospital London UK
7. Department of Epidemiology, University of Groningen University Medical Center Groningen Groningen The Netherlands
8. Department of Ophthalmology Oslo University Hospital Oslo Norway
9. Department of Ophthalmology Sørlandet Hospital Arendal Arendal Norway
10. Department of Quality and Health Technology, The Faculty of Health Sciences University of Stavanger Stavanger Norway