Effect of capsular tension ring implantation on capsular stability after phacoemulsification in patients with weak zonules: a randomized controlled trial. CTR implantation in cataract patients with weak zonules

Abstract

Background The use of capsular tension ring (CTR) implantation to treat cataract patients with weak zonules is still controversial. The aim of this study was to examine the effects of CTR implantation on capsular stability after phacoemulsification in patients with weak zonules, especially patients who have undergone pars plana vitrectomy (PPV) or those who suffer from severe myopia. Methods A total of 42 patients who underwent phacoemulsification and received an intraocular lens (IOL) were randomized to undergo CTR implantation or not. The control and CTR groups were compared in terms of uncorrected distant visual acuity (UDVA), best corrected distant visual acuity (BCDVA), refractive prediction error, the area of anterior capsulorhexis, and IOL inclination angle. Follow-up visits were conducted postoperatively at 1 day, 1 week, 1 month and 3 months. Subgroup analyses were performed based on PPV and severe myopia. Results Surgery significantly improved UDVA and BCDVA to similar extents in CTR and control patients, and refraction prediction error was similar between the two groups at all follow-up times. At 3 months after surgery, the area of anterior capsulorhexis was significantly larger in CTR patients than in controls (p = 0.0199). These differences were also significant between the subgroups of patients with severe myopia. Vertical IOL inclination was less within CTR groups at 3 months after surgery, especially in patients with severe myopia (p = 0.0286). At 1 week postoperatively, the proportion of individuals whose posterior lens capsule that had completely adhered to the posterior IOL surface was significantly higher among CTR patients (p = 0.023). No serious surgical complications were observed. Conclusion CTR implantation can benefit cataract patients with weak zonules by maintaining the shape of the capsular bag, reducing capsule shrinkage and stabilizing IOL inclination. Trial registration Chinese Clinical Trial Registry ChiCTR-INR-17011217, date of registration April 22, 2017, prospectively registered.

Clinical and laboratory studies on the effects of capsular tension ring on surgical outcomes of trifocal intraocular lens implantation

“…These results are in good agreement with previous studies. [21][22][23] It has been reported that the interspace between the IOL and the posterior capsule was reduced by the presence of CTR. 21,22 The distance between the IOL and the posterior capsule was detected in 35% of eyes having IOL without CTR, while the rate was 15% in eyes with IOL and CTR.…”

Intrascleral Intraocular Lens Fixation Preserving the Lens Capsule in Cases of Cataract with Insufficient Zonular Support

“…Based on this study, the persistence of the extended capsular diaphragm (the IOL-capsule-CTR complex) may prevent distortion. 6,30 Some reports have suggested that a CTR may inhibit (post-cataract) lens epithelial cell migration, 9 thus reducing the risk of capsulorhexis-optic contact 6 and progressive IOL tilting. 30 Our technique can be regarded as a modification of IOL optic capture.…”

“…6,30 Some reports have suggested that a CTR may inhibit (post-cataract) lens epithelial cell migration, 9 thus reducing the risk of capsulorhexis-optic contact 6 and progressive IOL tilting. 30 Our technique can be regarded as a modification of IOL optic capture. As reported by Gimbel and DeBroff, 14 IOL optic capture can be attained via various means; all afford long-term IOL stability and centration.…”

Simulated zonular tension analysis in the presence of zonular disinsertion

“…10,11 Clinical data to support these properties is limited. 12,13 Understanding the forces acting on the zonules in the presence of zonular weakness can help understand the pathogenesis of the late dropped IOL-bag complex and provide information for the development of improved CTRs and IOLs.…”