Purpose: To evaluate the effect of a closed foldable equator ring (CFER) versus a conventional capsular tension ring (CTR) on capsular bag shrinkage.
Setting: Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany.
Methods: In this prospective study, 70 eyes of 70 patients were randomized to 2 groups using a 1:1 block scheme. After uneventful cataract surgery, a capsular measuring ring was implanted in all eyes to measure the capsular bag diameter in vivo. In Group 1, a CTR was implanted in the capsular bag. In Group 2, a CFER was inserted. Biometric characteristics such as axial length and the horizontal and vertical corneal radii were measured preoperatively. The capsular bag diameter and capsulorhexis diameter were measured intraoperatively and 2 or 3 days as well as 1 and 3 months postoperatively.
Results: There were no statistically significant or clinically relevant between-group differences in covariants such as axial length, vertical and horizontal corneal radii, and capsulorhexis diameter. Eyes with the CTR had slight but statistically significant capsular bag shrinkage from a median of 10.4 to a median of 10.2 mm after 3 months (P<.001). Eyes with the CFER also had slight but statistically significant capsular bag shrinkage from a median of 10.3 to a median of 10.2 mm 3 months postoperatively (P = .021). At baseline, the CTR group had a larger capsular bag diameter, but there were no statistically significant differences between the groups at the 3-month follow-up (P = .669).
Conclusions: No clinically relevant capsular bag shrinkage was observed after implantation of a CFER or a CTR. The expected capsular bag shrinkage was the same in both groups.