Effect of capsular tension ring on optical and multifunctional lens position outcomes: a systematic review and a meta-analysis

To evaluate the effect of capsular tension rings with multifunctional lens position and optical outcomes.We defined multifunctional lens as more than improving vision, but also to restore visual quality. PubMed, EMBASE, Cochrane Library and Scopus were searched for English-language articles published up to November 11, 2020. Randomized controlled trials and comparative prospective clinical trials were selected. Data extraction was completed by independent pairs of reviewers. The risk of bias was evaluated using the Cochrane Collaboration's risk-of-bias tool for RCTs and select items from the Newcastle-Ottawa Scale for comparative prospective clinical trials.A total of 5 randomized controlled trials and 6 prospective comparative clinical trials were included. One thousand nine hundred and ninety-nine eyes of implantation intraocular lens were evaluated. Capsular tension ring was helpful in un-corrected distance visual acuity (SMD: 0.54, 95% CI = 0.15 to 0.94, p = 0.829) in 1st month. Contrary to 1st month, no show positive effect in 3rd month un-corrected distance visual acuity (SMD: - 0.30, 95% CI = - 0.70 to - 0.10, p = 0.311), corrected distance visual acuity (SMD: 0.02, 95% CI = - 0.78 to 0.81, p < 0.001), sphere (SMD: 0.44, 95% CI = - 0.43 to 1.31, p < 0.001), cylinder (SMD: - 0.12, 95% CI = - 0.36 to 0.13, p = 0.262), and spherical equivalent (SMD: 0.41, 95% CI = 0.13 to 0.69, p = 0.084). Our study also revealed low correlation between capsular tension ring and postoperative optical outcome with un-corrected distance visual acuity (SMD: 0.43, 95% CI = - 0.69 to 1.56, p = 0.001), corrected distance visual acuity (SMD: - 0.11, 95%CI = - 0.43 to 0.20, p = 0.56), sphere (SMD: - 0.26, 95%CI = - 1.18 to 0.66, p = 0.005), cylinder (SMD: 0.10, 95% CI = - 0.39 to 0.59, p = 0.075), spherical equivalent (SMD: 0.22, 95%CI = - 0.10 to 0.54, p = 0.849) in 6th month. The position of intraocular lens co-implantation with capsular tension ring has no significant difference in 1st week with lens decentration (SMD: - 0.34, 95% CI = - 1.19 to 0.51, p = 0.038) and tilt (SMD: - 1.00, 95% CI = - 2.19 to 0.19, p = 0.007), but capsular tension ring is helpful to prevent lens tilt in 1st month (SMD: - 0.67, 95%CI = - 1.08 to 0.27, p = 0.323). In 3rd month, there was no significant difference between two groups in lens rotation (SMD: - 0.51, 95%CI = - 1.71 to 0.69, p < 0.001).The correlation is low between capsular tension ring and postoperative optical outcomes and lens position, based on small numbers of studies in a short range of follow-up.