RT Journal Article SR Electronic T1 Tissue Differentiation with Ultrasound JF British Journal of Ophthalmology JO Br J Ophthalmol FD BMJ Publishing Group Ltd. SP 550 OP 550 DO 10.1136/bjo.61.8.550-b VO 61 IS 8 A1 Ffytche, T. J. YR 1977 UL http://bjo.bmj.com/content/61/8/550.3.abstract AB