1 Department of Ophthalmology, University of California, San Francisco, San Francisco, California.
2 Department of Ophthalmology, University of California, San Francisco, San Francisco, California; Center for Mind/Brain Sciences, The University of Trento, Trento, Italy.
3 Department of Ophthalmology, University of California, San Francisco, San Francisco, California. Electronic address: hortonj@vision.ucsf.edu.