1 NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK UCL Genetics Institute, London, UK.
2 NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK.
3 NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK London School of Hygiene & Tropical Medicine, London, UK.
4 Department of Primary Care and Population Health, University College London, London, UK.
5 UCL Comprehensive Clinical Trials Unit, University College London, London, UK.