RT Journal Article SR Electronic T1 Cochrane Eye and Vision Group JF British Journal of Ophthalmology JO Br J Ophthalmol FD BMJ Publishing Group Ltd. SP 764 OP 765 DO 10.1136/bjophthalmol-2011-300889 VO 96 IS 5 A1 Y C Yap A1 S Fraser A1 R Wormald YR 2012 UL http://bjo.bmj.com/content/96/5/764.abstract AB