Capsule measuring ring to predict capsular bag diameter and follow its course after foldable intraocular lens implantation

PURPOSE: To evaluate the extent of capsular bag shrinkage after cataract surgery with intraocular lens (IOL) implantation and develop a regression formula to predict postoperative capsular bag size. SETTING: Eye Hospital, Johannes Gutenberg-University, Mainz, Germany. METHODS: The axial length (AL), anterior chamber depth, and corneal radius in 58 eyes were measured preoperatively. Cataract surgery was by phacoemulsification followed by implantation of a 3-piece, acrylic, posterior chamber IOL. The capsular bag diameter and anterior capsulorhexis were measured intraoperatively and 1 day and 1, 3, and 6 months postoperatively using a Koch capsule measuring ring (HumanOptics). RESULTS: The mean capsular bag size was 10.53 mm intraoperatively, 10.31 mm at 1 day, 9.62 mm at 1 month, 9.07 mm at 3 months, and 9.01 mm at 6 months. The mean capsular bag shrinkage over the entire postoperative period was 14.8% (P<.001). Of the parameters studied, only AL had a positive correlation with capsule shrinkage. The correlation was moderate but statistically significant (P =.001). CONCLUSIONS: A correlation was found between capsular bag shrinkage and AL. Using preoperative biometric data, a regression formula of moderate validity was determined to predict capsular bag shrinkage.