Government of the United Kingdom - Moorfields Eye Hospital, NIHR Moorfields Biomedical Research Centre, NIHR Moorfields Biomedical Research Centre, University of London, Manchester University NHS Trust - Manchester Royal Eye Hospital, University College London - Institute of Ophthalmology, King’s College London, King’s College London, King’s College London - Department of Public Health Sciences, King’s College London - School of Population Health and Environmental Sciences, Newcastle University, Cardiff University - Centre for Trials Research, Torfaen County Borough Council - NIHR Health Determinants Research Collaboration Torfaen, Cardiff University - Department of Healthcare Sciences, Cardiff University - School of Healthcare Sciences, University of Plymouth - School of Nursing and Midwifery, Manchester University NHS Trust - Manchester Royal Eye Hospital, University Hospitals Bristol - University Hospitals Bristol NHS Foundation Trust, Leeds Teaching Hospitals NHS Trust, NHS Foundation Trust - Bradford Teaching Hospitals NHS Foundation Trust, King’s College London - School of Population Health and Environmental Sciences, University of Hull - Hull York Medical School, Government of the United Kingdom - Moorfields Eye Hospital, Government of the United Kingdom - Moorfields Eye Hospital, NIHR Moorfields Biomedical Research Centre, London School of Hygiene & Tropical Medicine, Government of the United Kingdom - Biomedical Research Centre and Moorfields Eye Hospital - Ophthalmic Reading Centre