title: Reply.
authors.affiliation: School of Clinical Sciences, University of Bristol and Bristol Eye Hospital, Bristol, United Kingdom.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Chu
authors.affiliation: Gloucestershire Eye Unit, Cheltenham General Hospital, Cheltenham, United Kingdom.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Johnston
authors.affiliation: Gloucestershire Eye Unit, Cheltenham General Hospital, Cheltenham, United Kingdom.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Buscombe
authors.affiliation: Gloucestershire Eye Unit, Cheltenham General Hospital, Cheltenham, United Kingdom.
authors.forename: Ahmed B
authors.initials: AB
authors.lastname: Sallam
authors.affiliation: Gloucestershire Eye Unit, Cheltenham General Hospital, Cheltenham, United Kingdom.
authors.forename: Quresh
authors.initials: Q
authors.lastname: Mohamed
authors.affiliation: Royal Wolverhampton Hospitals NHS Trust, New Cross, Wolverhampton, United Kingdom; Sandwell and West Birmingham NHS Trust, Birmingham, United Kingdom. Electronic address: yit.yang@nhs.net.
authors.forename: Yit C
authors.initials: YC
authors.lastname: Yang