1. Department of Ophthalmology, Tufts University Medical Center, Boston, Massachusetts, U.S.A.
2. Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, U.S.A.
3. Department of Ophthalmology, University of Illinois at Chicago, Illinois Eye & Ear Infirmary, Chicago, Illinois, U.S.A.
4. Department of Ophthalmology, Weill Cornell Medicine, New York-Presbyterian Hospital, New York, U.S.A.
5. Department of Neurological Surgery, Weill Cornell Medicine, New York-Presbyterian Hospital, New York, U.S.A.
6. Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, New York-Presbyterian Hospital, New York, U.S.A