1. Department of Public Health, Brigham Young University, Provo, Utah, USA
2. Department of Ophthalmology, University of Port Harcourt Teaching Hospital, Port Harcourt, Nigeria
3. Department of Ophthalmology, Stein Eye Institute, UCLA School of Medicine, Los Angeles, California, USA
4. Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, California, USA