1. From the International Centre for Eye Health, London School of Hygiene and Tropical Medicine, London, United Kingdom;2Medical Research Council Laboratories, Fajara, The Gambia; and the
2. Medical Research Council Laboratories, Fajara, The Gambia; and the
3. National Eye Care Programme, Ministry of Health, Banjul, The Gambia.
4. From the International Centre for Eye Health, London School of Hygiene and Tropical Medicine, London, United Kingdom;