The capsular tension ring: Designs, applications, and techniques

Originally, the open poly(methyl methacrylate) (PMMA) capsular tension ring (CTR) was designed to compensate for zonular defects or to stretch the pos terior capsule in highly myopic eyes not receiving an intraocular lens (IOL ). We address the variety of subsequent designs, applications, and techniqu es that have evolved. With pre-existing or intraoperative zonular defects, a standard CTR may be inserted before or at any time during cataract remova l to maintain or re-establish an extended capsular diaphragm. For profound zonular dialysis or weakness, a CTR was designed for scleral fixation. Caps ular tension rings with integrated tinted sector shields have been develope d to compensate for sector iris colobomas or aniridia. The CTR has also bee n used as a measuring gauge for in vivo quantification of capsule dimension s and postoperative capsular shrinkage. The CTR has improved control during primary posterior capsulorhexis and prevented oval distortion along the le ns axis postoperatively. During combined cataract and vitreous surgery, a C TR prevents capsule damage and provides undisturbed peripheral visualizatio n before IOL implantation. Capsular tension rings may also influence capsul e opacification formation. A special band-shaped CTR with sharp edges was d eveloped to inhibit lens epithelial cell migration and avoid capsulorhexis- optic contact. (C) 2000 ASCRS and ESCRS.