1. Cincinnati Eye Institute, University of Cincinnati College of Medicine, Department of Ophthalmology, Cincinnati, Ohio, USA
2. Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, USA
3. Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
4. Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
5. Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, USA