RT Journal Article SR Electronic T1 VOLUNTARY CONVERGENCE JF British Journal of Ophthalmology JO Br J Ophthalmol FD BMJ Publishing Group Ltd. SP 34 OP 35 DO 10.1136/bjo.27.1.34 VO 27 IS 1 A1 W. R. Mathewson YR 1943 UL http://bjo.bmj.com/content/27/1/34.abstract AB