Efficacy and safety of capsular bending ring implantation to prevent posterior capsule opacification: three-year results of a randomized clinical trial

J Cataract Refract Surg. 2008 Aug;34(8):1318-28. doi: 10.1016/j.jcrs.2008.04.034.


Purpose: To determine whether a capsular bending ring (CBR) with a rectangular cross-section and sharp edges moves the barrier to the very equator and avoids contact between the capsulorhexis and optic to prevent posterior capsule opacification (PCO) and anterior capsule fibrosis.

Setting: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

Methods: A 0.7 mm high, open poly(methyl methacrylate) CBR was implanted in 60 eyes (patients) in a prospective randomized intraindividual trial. The impact of additional CBR implantation on PCO and anterior capsule fibrosis was compared to that of intraocular lens (IOL) implantation alone using objective scoring.

Results: No CBR-related surgical complications occurred. The objective PCO score and area were statistically significantly reduced in the CBR group. In patients with complete follow-up, the mean PCO score (scale 1 to 10) at 1, 2, and 3 years was 0.8, 1.7, and 2.1, respectively, in the CBR group and 2.6, 3.9, and 4.6, respectively, in the no-CBR group. The number of quadrants affected by PCO was 0.9, 1.5, and 1.8 versus 3.2, 3.8, and 3.8. Barrier failures with the CBR were caused by the inherent slight edge blunting and occasional eyelet gaping. Laser capsulotomies were performed in the no-CBR group only. Capsule stress folds and fibrotic anterior capsule opacification were also greatly reduced. The best corrected visual acuity was better in the CBR group.

Conclusions: Capsular bending ring implantation was an effective and safe adjunct to in-the-bag IOL fixation. With improvements in technology and design securing exquisitely sharp edges and circumferential capsular bending independent of the capsular bag diameter, this concept has the potential to prevent PCO and anterior capsule fibrosis.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Cataract / prevention & control*
  • Equipment Safety
  • Female
  • Fibrosis / prevention & control
  • Humans
  • Lens Capsule, Crystalline / pathology
  • Lens Capsule, Crystalline / surgery*
  • Lens Implantation, Intraocular / instrumentation
  • Male
  • Middle Aged
  • Polymethyl Methacrylate
  • Postoperative Complications / prevention & control*
  • Prospective Studies
  • Prostheses and Implants*
  • Prosthesis Implantation*
  • Treatment Outcome
  • Visual Acuity


  • Polymethyl Methacrylate