RT Journal Article SR Electronic T1 THE OPTICAL CONVENTION JF British Journal of Ophthalmology JO Br J Ophthalmol FD BMJ Publishing Group Ltd. SP 345 OP 346 DO 10.1136/bjo.10.6.345 VO 10 IS 6 YR 1926 UL http://bjo.bmj.com/content/10/6/345.abstract AB