1. Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
2. Department of Ophthalmology, Shaare Zedek Medical Center Affiliated with the Hebrew University, Hadassah School of Medicine, Jerusalem, Israel
3. Department of Behavioral and Community Health Sciences, Graduate School of Public Health, University of Pittsburgh; and Department of Family Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
4. Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina; andDurham Veterans Affairs Medical Center, Health Services Research and Development, Durham, North Carolina