[1] Victoria Infirm, Glasgow G42 9TY, Lanark, Scotland
[2] Glasgow Caledonian Univ, Nursing Midwifery & Allied Hlth Profess NMAHP Res, Glasgow G4 0BA, Lanark, Scotland
[3] Gartnavel Royal Hosp, Tennent Inst Ophthalmol, Glasgow, Lanark, Scotland
[4] Royal Hosp Sick Children, Glasgow G3 8SJ, Lanark, Scotland
[5] Glasgow Caledonian Univ, Dept Vis Sci, Glasgow G4 0BA, Lanark, Scotland
[6] Western Gen Hosp, Edinburgh EH4 2XU, Midlothian, Scotland
[7] Royal Perth Hosp, Perth, WA, Australia
[8] Princess Alexandra Eye Pavil, Edinburgh, Midlothian, Scotland