Efficacy of complete rings (MyoRing) in treatment of Keratoconus: a systematic review and meta-analysis
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).
KeywordsCornea 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.
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.
- 2.Caporossi A, Baiocchi S, Mazzotta C, Traversi C, Caporossi T (2006) Parasurgical therapy for keratoconus by riboflavin-ultraviolet type A rays induced cross-linking of corneal collagen; preliminary refractive results in an Italian study. J Cataract Refract Surg 32:837–845CrossRefPubMedPubMedCentralGoogle Scholar
- 3.Sykakis E, Karim R, Evans JR, Bunce C, Amissah-Arthur KN, Patwary S et al (2015) Corneal collagen cross-linking for treating keratoconus. Cochrane Libr 24(3):CD010621Google Scholar
- 8.Zadnik K, Lindsley K (2014) Intrastromal corneal ring segments for treating keratoconus (Protocol). Cochrane Libr 6:011150Google Scholar
- 15.Al-Tuwairqi W (2015) Comparison of 2 types of intrastromal corneal rings in visual function improvement and Keratoconus outcomes. In: ASCRS. ASOA Symposium and CongressGoogle Scholar
- 16.Saleem MI (2015) Comparison of implantation of 2 ICRS using femtosecond laser for treatment of Keratoconus. In: ASCRS. ASOA Symposium and CongressGoogle Scholar
- 20.Hosny M (2014) Complete Ring Versus ICRS Femtosecond Laser-Assisted Implantation for Keratoconus. In: The annual ASCRS and ASOA symposium and congressGoogle Scholar
- 25.Studeny P, Krizova D, Stranak Z (2014) Clinical outcomes after complete intracorneal ring implantation and corneal collagen cross-linking in an intrastromal pocket in one session for Keratoconus. J Ophthalmol 2014:568128Google Scholar
- 26.Studený P, Křížová D, Straňák Z, Kuchynka P (2015) Clinical results after continuous corneal ring (MyoRing) implantation in Keratoconus patients. Ceska a slovenska oftalmologie: casopis Ceske oftalmologicke spolecnosti a Slovenske oftalmologicke spolecnosti 71(2):87–91Google Scholar
- 27.Pashtayev NP, Sinitsyn MV, Pozdeyeva NA (2014) Comparative analysis of clinical and functional results of the intrastromal segments and MyoRing implantations in keratoconus using the femtosecond technology. Oftal’mokhirurgiya 1(3):35Google Scholar
- 32.Bikbov M, Bikbova G (2012) Intrastromal corneal MyoRings with corneal collagen cross-linking in keratoconus treatment. Ophthalmosurgery 4:6–9Google Scholar
- 33.Zhadan VA, Lebedev OI, Kalyzhnikova EA (2014) Intrastromal keratoplasty with MyoRing implantation in surgical treatment of keratoconus. Preliminary results. Oftal’mokhirurgiya 1(3):31Google Scholar
- 34.Daxer A, Ettl A, Hörantner R (2016) Long-term results of MyoRing treatment of keratoconus. J Optom 10(2):123–129Google Scholar
- 38.Nobari SM, Villena C, Jadidi K (2014) Predictability, stability and safety of MyoRing implantation in Keratoconic eyes during one year follow-up. Iran J Ophthalmol 26(3):136–143Google Scholar
- 47.Keratoconus International. https://www.keratoconusinternational.com/cisis-myoring/myoring-long-term-results