1. University of North Carolina, Chapel Hill, North Carolina, United States
2. Wilmer Eye Institute, Baltimore, Maryland, United States
3. Duke University Eye Center, Durham, North Carolina, United States
4. Vance Thompson Vision, Sioux Falls, South Dakota, United States
5. Ruprecht-Karls University, Heidelberg, Germany
6. Beijing Tongren Eye Hospital, Beijing, China
7. Mayo Clinic, Rochester, Minnesota, United States