1. From the Institute of Ophthalmology, University College London, London, United Kingdom; the
2. Section of Medical and Molecular Genetics, Department of Paediatrics and Child Health, University of Birmingham, Birmingham, United Kingdom; the4West Midlands Regional Genetics Service, Birmingham Women’s Hospital, Birmingham, United Kingdom; the
3. Department of Ophthalmology, Birmingham Children’s Hospital, Birmingham, United Kingdom; and the
4. Department of Experimental Psychology, University of Cambridge, Cambridge, United Kingdom.