1. From the New England Eye Center, Tufts Medical Center, Boston, Massachusetts; the 2Boston University School of Medicine, Boston, Massachusetts;
2. From the New England Eye Center, Tufts Medical Center, Boston, Massachusetts;
3. the Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts; and
4. the University of Pittsburgh Medical Center Eye Center, Eye and Ear Institute, Pittsburgh, Pennsylvania.