Efficacy of complete rings (MyoRing) in treatment of Keratoconus: a systematic review and meta-analysis.

PURPOSE: We aimed to systematically review the existing evidence and determine the efficacy of MyoRing as a novel method for treatment of keratoconus using meta-analysis. METHODS: Online electronic search of Medline, ISI Web of Science, Embase, Scopus, and Cochrane Library databases was performed with reference lists of relevant articles for pre-post trials published through August 2017. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), sphere, cylinder, spherical equivalent (SE), maximum, minimum, and mean keratometry were considered as the visual acuity outcomes. Weighted mean difference (WMD) with 95% confidence interval was used as pooled estimation of intervention efficacy using random-effects meta-analysis. Heterogeneity was measured with the Cochran Q statistic and quantified with the I2 statistic using Stata software. RESULTS: Of the 47 potentially related studies, 21 eligible studies were included in the meta-analysis. The mean of uncorrected distance visual acuity (UDVA) based on LogMAR in patients with keratoconus had a significant change 3 months after implantation/embedding of the complete ring (WMD =  - 0.73 (CI = - 0.88 to - 0.58), I2 = 79.9%, p