[1] Royal Liverpool & Broadgreen Hosp NHS Trust, Ophthalmol, Liverpool, Merseyside, England
[2] Arcispedale S Maria Nuova, UOSD Glaucoma, Reggio Emilia, Italy
[3] Sunderland Eye Infirm, Ophthalmol, Sunderland, England
[4] Royal Liverpool & Broadgreen Univ Hosp NHS Trust, St Pauls Eye Unit, Liverpool, Merseyside, England