1. Department of Neuro-Ophthalmology, The National Hospital for Neurology and Neurosurgery, Box 93, Queen Square, London WC1N 3BG, UK
2. Service d’ophtalmologie, Hôpital Universitaire Necker-Enfants malades, AP-HP, Rue de Sèvres, 75015 Paris, France
3. St. Thomas’ Hospital, London, UK