1. Retina Center of Minnesota, Minneapolis, MN, USA
2. VitreoRetinal Surgery, PA, Minneapolis, MN, USA
3. The Retina Institute, St. Louis, MO, USA
4. Mid Atlantic Retina, Wills Eye Hospital, Philadelphia, PA, USA
5. Associated Retinal Consultants of Michigan, Royal Oak, MI, USA
6. Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA, USA