1. Department of Neurosurgery, College of Physicians and Surgeons of Columbia University, New York, New York
2. Department of Ophthalmology, College of Physicians and Surgeons of Columbia University, New York, New York
3. Tufts-New England Medical Center, Boston, Massachusetts, and Department of Neurosurgery, College of Physicians and Surgeons of Columbia University, New York, New York
4. Department of Pathology, College of Physicians and Surgeons of Columbia University, New York, New York