1. Queen Alexandra Hospital; Department of Ophthalmology; Cosham Portsmouth Hampshire UK PO6 3LY
2. Southampton General Hospital; Department of Ophthalmology, Southampton Eye Unit; Tremona Road Southampton UK S016 6YD
3. London School of Hygiene & Tropical Medicine; Cochrane Eyes and Vision Group, ICEH; Keppel Street London UK WC1E 7HT