1. Centre for Public Health, School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Northern, Ireland, UK
2. Programmes Department, Vision Aid Overseas, London, UK
3. College of Health Sciences, University of KwaZulu Natal, Durban, South Africa
4. Department of Primary Eye Care Unit, Ministry of Health, Zanzibar, Tanzania
5. Independent researcher, Nairobi, Kenya
6. Research Department, Vision Care Foundation, Dar-es-Salaam, Tanzania