RT Journal Article SR Electronic T1 Blood flow in the Zinn–Haller circle JF British Journal of Ophthalmology JO Br J Ophthalmol FD BMJ Publishing Group Ltd. SP 1351 OP 1352 DO 10.1136/bjo.82.12.1351 VO 82 IS 12 A1 GORDON RUSKELL YR 1998 UL http://bjo.bmj.com/content/82/12/1351.abstract AB