1. Department of Education University of Agder Kristiansand Norway
2. Norwegian Quality and Surveillance Registry for Cerebral Palsy (NorCP) Vestfold Hospital Trust Tønsberg Norway
3. Department of Clinical and Molecular Medicine Norwegian University of Science and Technology Trondheim Norway
4. Department of Ophthalmology Oslo University Hospital Oslo Norway
5. Department of Ophthalmology Haukeland University Hospital Bergen Norway
6. Department of Clinical Medicine K1 University of Bergen Bergen Norway
7. Statped National Service for Special Needs Education Bergen Norway
8. Department of Special Needs Education University of Oslo Oslo Norway
9. Department of Clinical Neurosciences for Children Oslo University Hospital Oslo Norway