Optimal Implantation Time for a Capsular Tension Ring

P erforming cataract extraction in patients with zonular weakness presents many challenges and increases the risk of intraand postoperative complications. Capsular tension rings (CTRs) and other endocapsular support devices have been important management options for patients with significant zonulopathy. Hara et al1 and Nagamato and Bissen-Miyajima2 introduced the first endocapsular devices, but they were popularized and further developed by U.F.C. Legler and B.M. Witschel.3 The standard CTR is an open polymethyl methacrylate (PMMA) ring with rounded eyelets on both free ends. The CTR may serve a dual purpose, providing intraoperative support during cataract extraction and serving as an implant for long-term IOL stabilization. The diameter of the CTR is larger than that of the capsular bag, allowing the centrifugal forces inherent in the ring to expand the capsular equator, buttress the weak areas, and provide equal distribution of support over the remaining zonules.4 The CTR also recruits tension from existing zonules and redistributes the forces to the remaining weaker zonules to stabilize the entire zonular apparatus,3 and it tautens the posterior capsule during surgery to prevent capsular shrivelling so that Nd:YAG laser capsulotomy may be performed after phacoemulsification.5 There is also a decreased prevalence of posterior capsular opacification in patients with CTRs.6