1. International Center for Epidemiologic and Preventive Ophthalmology, The Wilmer Institute
2. School of Hygiene and Public Health, The Johns Hopkins University, Baltimore, Maryland
3. Flinders Medical Centre, Bedford Park, South Australia
4. Division of Geographic Medicine, Case Western Reserve University and University Hospitals, Cleveland, Ohio
5. Cornell University, Ithaca, New York
6. Liberian Institute for Biomedical Research, Robertsfield, Liberia