1. Department of Ophthalmology; University of Colorado Anschutz Medical Campus, School of Medicine; Aurora Colorado USA
2. Department of Epidemiology; University of Colorado Anschutz Medical Campus, School of Public Health; Aurora Colorado USA
3. Wilmer Eye Institute; Johns Hopkins University School of Medicine; Baltimore Maryland USA
4. Surgery, Division of Ophthalmology; University of Vermont; Burlington Vermont USA
5. Special Volunteer, National Eye Institute; Sacramento California USA