1 Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Neurology, MS Center and Neuro-ophthalmology Expertise Center, Neuroscience Amsterdam, Amsterdam, The Netherlands.
2 Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Ophthalmology, Neuro-ophthalmology Expertise Center, Neuroscience Amsterdam, Amsterdam, The Netherlands.
3 Moorfields Eye Hospital, The National Hospital for Neurology and Neurosurgery and the Queen Square Institute of Neurology, UCL, London, UK.