1. Department of Ophthalmology, New York University School of Medicine, New York, New York, United States
2. Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
3. Department of Neurology, Johns Hopkins University, Baltimore, Maryland, United States
4. Department of Ophthalmology, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
5. Department of Neurology, University Hospitals, Case Western Reserve University, Cleveland, Ohio, United States
6. Daroff-Dell'Osso Ocular Motility Laboratory, Cleveland VA Medical Center, Cleveland, Ohio, United States