1. International Centre for Eye Health; London School of Hygiene and Tropical Medicine; London UK
2. Department of Ophthalmology; University of Nairobi; Nairobi Kenya
3. PCEA Kikuyu Eye Unit; Kikuyu Kenya
4. Kitale District Hospital; Kitale Kenya
5. Sabatia Eye Hospital; Wodanga Kenya
6. Kenyatta National Hospital; Nairobi Kenya
7. Department of Pathology; MP Shah Hospital; Nairobi Kenya
8. KAVI Institute of Clinical Research; University of Nairobi; Nairobi Kenya
9. UCL Institute of Ophthalmology; London UK
10. Moorfields Eye Hospital; London UK
11. St. Bartholomew's Hospital; London UK
12. MRC Tropical Epidemiology Group; London School of Hygiene and Tropical Medicine; London UK