1. Department of Ear, Nose and Throat Østfold Hospital Trust, Kalnes Moss Norway
2. Department of Ophthalmology, Division of Head, Neck and Reconstructive Surgery Oslo University Hospital Oslo Norway
3. Department of Twin Research & Genetic Epidemiology, King's College London St Thomas’ Hospital London UK
4. Department of Computer Science Oslo Metropolitan University Oslo Norway
5. Department of Plastic and Reconstructive Surgery Oslo University Hospital Oslo Norway
6. Department of Medical Biochemistry Oslo University Hospital Oslo Norway
7. Department of Ophthalmology, University of Groningen University Medical Center Groningen Groningen Netherlands
8. Department of Ophthalmology Sørlandet Hospital Arendal Arendal Norway
9. Dutch Dry Eye Clinic Velp Netherlands
10. Department of Ophthalmology Vestfold Hospital Trust Tønsberg Norway