1. Department of Ophthalmology, College of Medicine, King Saud University
RiyadhSaudi Arabia
2. Kilimanjaro Centre for Community Ophthalmology International, Division of Ophthalmology, University of Cape Town
Cape TownSouth Africa
3. School of Population and Public Health
4. British Columbia Centre for Epidemiologic and International Ophthalmology, University of British Columbia
VancouverCanada