1 International Centre for Eye Health, Clinical Research Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK; School of Population Health, Faculty of Medicine and Health Sciences, University of Auckland, Auckland, New Zealand. Electronic address: j.ramke@auckland.ac.nz.
2 Medical Education Unit, Office of the Vice Chancellor, Baze University, Abuja, Nigeria.