1. Department of Population and Data Sciences University of Texas Southwestern Medical Center Dallas Texas USA
2. Department of Ophthalmology University of Pennsylvania Philadelphia Pennsylvania USA
3. Division of Pediatric Ophthalmology Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
4. Department of Biostatistics, School of Public Health Peking University Beijing China
5. Beijing International Center for Mathematical Research Peking University Beijing China
6. Department of Biostatistics, Epidemiology and Informatics University of Pennsylvania Philadelphia Pennsylvania USA
7. Leonard Davis Institute of Health Economics Philadelphia PA USA
8. Institute for Biomedical Informatics, The Perelman School of Medicine University of Pennsylvania Philadelphia PA USA