1. Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
2. Department of Cornea and External Diseases, Aravind Eye Care System, Madurai, India
3. Department of Cornea and External Diseases, Aravind Eye Care System, Madurai, India 3Department of Ocular Microbiology, Aravind Eye Care System, Madurai, India
4. Department of Cornea and External Diseases, Aravind Eye Care System, Coimbatore, India
5. Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, United States
6. Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States 5Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, United States
7. Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States 5Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, United States 6Department of Epidemiology an