1. From the Howe Laboratory and
2. Hafter Research Laboratories, Pennsylvania College of Optometry, Elkins Park, Pennsylvania; the
3. Berman-Gund Laboratory for the Study of Retinal Degenerations, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts;
4. Departments of Cell Biology and5Ophthalmology, University of Oklahoma College of Medicine, Oklahoma City, Oklahoma; and the
5. Department of Physiological Science and7Jules Stein Institute, University of California at Los Angeles, Los Angeles, California.