1. Malawi–Liverpool–Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, College of Medicine, Blantyre, Malawi
2. Department of Eye and Vision Science, University of Liverpool, Liverpool
3. International Centre for Eye Health, Clinical Research Department, London School of Hygiene and Tropical Medicine, London
4. St Pauls Eye Unit, Royal Liverpool University Teaching Hospital
5. International Health Group, Liverpool School of Tropical Medicine, Liverpool, UK