RT Journal Article SR Electronic T1 Focimeter JF British Journal of Ophthalmology JO Br J Ophthalmol FD BMJ Publishing Group Ltd. SP 593 OP 593 VO 92 IS 5 A1 Richard Keeler A1 Arun Singh A1 Harminder Dua YR 2008 UL http://bjo.bmj.com/content/92/5/593.abstract AB