University of Cambridge (JOTB, PY-W-M, BSC), Cambridge, United Kingdom; Cambridge University Hospitals NHS Foundation Trust (JOTB, PY-W-M, BSC), Cambridge, the United Kingdom; and Moorfields Eye Hospital NHS Foundation Trust (PY-W-M), London, the United Kingdom.

Address correspondence to: John O. T. Britton, BMBS, John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, E.D. Adrian Building, Forvie Site, Robinson Way, Cambridge CB2 0PY, United Kingdom; E-mail: [email protected]

The authors report no conflicts of interest.