[1] Liverpool Univ Hosp NHS Fdn Trust, Dept Clin Engn, Liverpool L7 8YE, England
[2] Liverpool Univ Hosp NHS Fdn Trust, NHS Digital, Liverpool L7 8YE, England
[3] Univ Liverpool, Dept Mol & Canc Med, Liverpool Ocular Oncol Res Grp, Liverpool L7 8TX, England
[4] Liverpool Univ Hosp NHS Fdn Trust, Liverpool Ocular Oncol Ctr, Liverpool L7 8TX, England
[5] Univ Hosp Bristol & Weston NHS Fdn Trust, Dept Clin Engn, Bristol BS2 8HW, England
[6] St Eriks Eye Hosp, S-17164 Stockholm, Sweden
[7] Karolinska Inst, S-17164 Stockholm, Sweden
[8] Univ Manchester, Manchester Ctr Hlth Econ, Div Populat Hlth Hlth Serv Res & Primary Care, Manchester M13 9PL, England