1. Department of Ophthalmology, the University of California San Diego Shiley Eye Center (MC 0946), 9415 Campus Point Drive, La Jolla, CA 92093, USA
2. International Centre for Eye Health, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
3. Belize Council for the Visually Impaired, Belize City, Belize