International Ophthalmology

, Volume 39, Issue 12, pp 2929–2946 | Cite as

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

  • Leila Janani
  • Kiarash Tanha
  • Fereshteh Najafi
  • Khosrow Jadidi
  • Farhad Nejat
  • Seyed Javad Hashemian
  • Mohsen Dehghani
  • Masoumeh SadeghiEmail author



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.


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.


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 < 0.001). Results support a statistically significance improvement in CDVA, SE, sphere, cylinder, and maximum keratometry after surgical intervention. Range of reported safety index, stability, and efficacy index by included studies was 1.7–2.7, 74–100%, and 0.9–1.96, respectively.


MyoRing is an appropriate treatment option for keratoconus. Findings of this meta-analysis demonstrated that main visual outcomes have been improved 3, 6, and 12 months after the implantation of the complete ring (MyoRing).


Cornea Keratoconus MyoRing Systematic review Meta-analysis 



We thank native English speaking editor from Birmingham Research Park (United Kingdom) for improving the use of English in the manuscript.

Authors’ contributions

LJ, KJ, and FN conceived the idea and designed the study. KT, LJ, and FN collected data, reviewed literature, and extracted data. KT, LJ, and MS, and MD participated in the analysis of data and interpreted the results. LJ, MD, and MS conceived the study aims and design, provide the data and measures, and designed the analysis. KJ, FN, and SJH reanalyzed data, made substantial contribution to interpretation of data, drafting the manuscript and revising it critically for important intellectual content and final approval of the version to be submitted and any revised version. All authors reviewed, discussed, provided critical comments, and approved the final manuscript. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication.


This study was partially supported by funds from Vice-Chancellor for Research of Iran University of Medical Sciences (IUMS), Tehran, Iran (Grant Number:94-05-27-27457). The funding sources had no role in study design, data collection, analysis, interpretation, and preparation of the manuscript.

Compliance with ethical standards

Conflict of interest

The authors declared that they have no conflict of interest.


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Copyright information

© Springer Nature B.V. 2019

Authors and Affiliations

  • Leila Janani
    • 1
    • 2
  • Kiarash Tanha
    • 1
  • Fereshteh Najafi
    • 3
    • 4
  • Khosrow Jadidi
    • 5
  • Farhad Nejat
    • 5
  • Seyed Javad Hashemian
    • 6
  • Mohsen Dehghani
    • 7
  • Masoumeh Sadeghi
    • 8
    Email author
  1. 1.Department of Biostatistics, School of Public HealthIran University of Medical SciencesTehranIslamic Republic of Iran
  2. 2.Preventive Medicine and Public Health Research CenterIran University of Medical SciencesTehranIslamic Republic of Iran
  3. 3.Torbat Heydariyeh University of Medical SciencesTorbat HeydariyehIslamic Republic of Iran
  4. 4.Department of Epidemiology and Biostatistics, School of Public HealthTehran University of Medical SciencesTehranIslamic Republic of Iran
  5. 5.Department of OphthalmologyBina Eye Hospital Research CenterTehranIslamic Republic of Iran
  6. 6.Eye Research Center, Rassoul Akram HospitalIran University of Medical SciencesTehranIslamic Republic of Iran
  7. 7.Department of Epidemiology, School of Public HealthIran University of Medical SciencesTehranIslamic Republic of Iran
  8. 8.Department of Epidemiology, School of Health and SafetyShahid Beheshti University of Medical SciencesTehranIslamic Republic of Iran

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