1 F.I. Proctor Foundation, University of California San Francisco, 513 Parnassus, Medical Sciences 309A, San Francisco, CA, 94143-0944, USA.
2 Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA.
3 Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA.
4 Programme FSS/Université Abdou Moumouni de Niamey, Programme National de Santé Oculaire, Niamey, Niger.
5 Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA.
6 Clinical Research Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
7 F.I. Proctor Foundation, University of California San Francisco, 513 Parnassus, Medical Sciences 309A, San Francisco, CA, 94143-0944, USA. tom.lietman@ucsf.edu.
8 Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA. tom.lietman@ucsf.edu.
9 Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA. tom.lietman@ucsf.edu.