University of Liverpool - Department of Eye and Vision Science, University of Liverpool - Diabetes & Endocrinology Research and Pain Research Institute, University of Liverpool - Diabetes & Endocrinology Research and Pain Research Institute, University of Liverpool - Diabetes & Endocrinology Research and Pain Research Institute, The University of Manchester - Division of Cardiovascular Sciences, The University of Manchester - Department of Neurology, The University of Manchester - Department of Neurology, The University of Manchester - Department of Neurology, Cornell University - Department of Medicine, Cornell University - Department of Medicine, Cornell University - Department of Medicine, Cornell University - Department of Medicine, Hamad Medical Corporation - Neuroscience Institute, Hamad Medical Corporation - Neuroscience Institute, University of Alberta - Department of Medicine, Hamad Medical Corporation - Geriatric & Memory Clinic, Hamad Medical Corporation - Geriatric & Memory Clinic, The University of Manchester - Division of Cardiovascular Sciences, University of Liverpool - Department of Eye and Vision Science and University of Liverpool - Diabetes & Endocrinology Research and Pain Research Institute