1 Birmingham and Midland Eye Centre, Birmingham, UK; Academic Unit of Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2TT, UK; Academic Ophthalmology, School of Medicine, University of Nottingham, Nottingham, UK. Electronic address: ting.darren@gmail.com.
2 International Centre for Eye Health, London School of Hygiene and Tropical Medicine, London, UK; Leeds Teaching Hospitals NHS Trust, Leeds, UK.