[1] Univ Edinburgh, NHS Lothian & Ctr Clin Brain Sci, Princess Alexandra Eye Pavil, Edinburgh, Scotland
[2] Univ Edinburgh, Edinburgh, Scotland
[3] Univ Dundee, Sch Sci & Engn, Dundee, Scotland
[4] NHS Tayside, Ninewells Hosp, Dept Ophthalmol, Dundee, Scotland
[5] Univ Edinburgh, Dept Ophthalmol, Princess Alexandra Eye Pavil, Chalmers St, Edinburgh EH3 9HA, Scotland