1. Department of Ophthalmology, Southern California Permanente Medical Group, Baldwin Park, California
2. Department of Research and Evaluation, Southern California Permanente Medical Group, Pasadena, California
3. Beetham Eye Institute, Joslin Diabetes Center, Boston, Massachusetts
4. Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
5. Department of Clinical Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland
6. Department of Ophthalmology, University of Wisconsin, Madison, Wisconsin