1. From the Schepens Eye Research Institute, Department of Ophthalmology, Boston, Massachusetts; 2Harvard Medical School, Boston, Massachusetts;
2. Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia; and
3. Harvard Medical School, Boston, Massachusetts; 4Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.
4. From the Schepens Eye Research Institute, Department of Ophthalmology, Boston, Massachusetts; 2Harvard Medical School, Boston, Massachusetts; 4Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.