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

Abstract

Background: Patients who had previously undergone pars plana vitrectomy (PPV) or who had severe myopia may have weaker zonules, for which a capsular tension ring (CTR) implantation is still controversial. This study is to test the effect of CTR implantation on capsular stability after phacoemulsification in those patients. Methods: A total of 42 patients who underwent phacoemulsification and received an intraocular lens (IOL) were randomized to undergo CTR implantation or not. The primary outcomes were 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. Outcomes were compared between all CTR and control patients, as well as between subgroups who had previously undergone PPV or who had 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 strong 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.