Effect of a capsular tension ring on the shape of the capsular bag and opening and the intraocular lens

Purpose: To evaluate the effect of a capsular tension ring (CTR) on the shape of the capsular bag, the extent of the capsular opening, and the shape of intraocular lenses (IOLs). Setting: Department of Ophthalmology, College of Medicine, The Catholic University of Korea, Seoul, Korea. Methods. The corneal button was removed from porcine eyes in vitro. After phacoemulsification was performed, an IOL alone or an IOL and CTR were inserted in the capsular bag in 6 groups of 5 eyes each. The eyes were examined from the posterior aspect using a Miyake technique to assess capsular bag shape and the capsular opening. To evaluate effects of the CTR on IOL shape, rabbit eyes had phacoemulsification and IOL Implantation with and without placement of a CTR in vivo. The IOLs were removed from enucleated eyes 3 months postoperatively and compared with unused control IOLs. Results: The differences between the maximum and minimum diameters of the capsular bags and capsular openings were significantly less in groups with a CTR. Intraocular lens size (difference from haptic to haptic) decreased significantly in eyes with only an IOL compared with normal controls or eyes with both an IOL and CTR. Conclusions: The CTR preserved the integrity of the capsular bag diameter, capsular opening, and IOL shape. It is likely that CTR implantation can avert contracture of the capsular bag and capsular opening, preventing IOL decentralion. (C) 2001 ASCRS and ESCRS.