1. Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock
2. Department of Ophthalmology, Faculty of Medicine, Assiut University, Assiut, Egypt
3. Department of Ophthalmology, University of Ottawa, Ottawa, Ontario, Canada
4. School of Clinical Sciences, University of Bristol and Bristol Eye Hospital, Bristol, United Kingdom
5. Wolverhampton Eye Infirmary, Royal Wolverhampton Hospitals National Health Service Trust, New Cross, Wolverhampton, United Kingdom
6. Sandwell and West Birmingham National Health Service Trust, Birmingham, United Kingdom
7. Ophthalmology Department, Gloucestershire Hospitals National Health Service Trust, Cheltenham, United Kingdom