1. Institute of Ophthalmology, Department of Clinical Ophthalmology, London
2. Department of Ophthalmology, United Medical and Dental Schools of Guy's and St. Thomas's Hospitals, University of London, London - U.K.
3. Department of Ophthalmology, St. Thomas’ Hospital, London - U.K.
4. Department of Ophthalmology, University of Kansas Medical Center, Kansas City, Kansas - U.S.A.