1. Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, Missouri, USA
2. Department of Paediatrics, Washington University in St. Louis, St. Louis, Missouri, USA
3. Division of Paediatric Neurology, Department of Neurology, Washington University in St. Louis, St. Louis, Missouri, USA
4. Neurology Consultants of Kansas, Wichita, Kansas, USA