[1] NHS Greater Glasgow & Clyde, Tennent Inst Ophthalmol, Glasgow, Lanark, Scotland
[2] NHS Greater Glasgow & Clyde, Royal Hosp Children, Glasgow, Lanark, Scotland
[3] Univ Strathclyde, Dept Biomed Engn, Glasgow, Lanark, Scotland
[4] NHS Forth Valley, Dept Ophthalmol, Falkirk, Scotland