Efficacy And Safety Of Intracorneal Ring Segments For The Treatment Of Residual Astigmatism Following Penetrating Keratoplasty: A Systematic Review And Meta-Analysis
Published 2024 - 42nd Congress of the ESCRS
Reference: PO822 | Type: Free paper | DOI: 10.82333/e87z-7f12
Authors: Siddharth Nath* 1 , Nicole Zhang 1 , Andrew Farah 1 , Brendan Tao 2 , Hamza Ahmad 1 , Ayman Aljohani 1 , Guillermo Rocha 1 , Mahshad Darvish-Zargar 1 , Julia Talajic 3 , Johanna Choremis 1
1McGill University,Montreal,Canada, 2University of British Columbia,Vancouver,Canada, 3Université de Montréal,Montreal,Canada
Purpose
Residual astigmatism following penetrating keratoplasty (PKP) is a considerable challenge. There exist a myriad of surgical options, including excimer laser ablation, wedge resection, and astigmatic keratotomy, however, all of these irreversibly alter treated tissue, and predicting the final refractive outcome is often difficult. To address these challenges, some surgeons have piloted placement of intracorneal ring segments (ICRSs), which have long been used to flatten the cornea in the setting of ectasia. ICRSs have the benefit of being reversible and there are established nomograms for predicting their refractive effect. The purpose of this study is to examine the safety and efficacy of ICRSs in the management of post-PKP astigmatism.
Setting
The setting of this study is a systematic review and meta-analysis. Our study was performed in line with the Preferred Reporting Items for Systematic Revews and Meta-Analyses (PRISMA) 2020 consensus statement and the Cochrane Collaboration's Handbook for Systematic Reviews of Interventions. All work was conducted in an academic health sciences centre with appropriate bibliographic, statistical, and methodological support.
Methods
We searched 16 electronic databases, including MEDLINE, Embase, and Web of Science, from inception until February 2, 2024, for studies evaluating the use of ICRSs for the treatment of residual astigmatism post-PKP. Our search was conducted without any language or study type restrictions, and we supplemented our database search with screening of the grey literature and hand searching of references. Our primary outcome was the change in refractive astigmatism post-ICRS placement. Secondary outcomes included the best-corrected visual acuity (BCVA), the maximum keratometry (Kmax), and the spherical error, after ICRS placement. Our analyses were summarized by calculating weighted mean differences with associated 95% confidence intervals.
Results
Six observational studies (150 eyes) were eligible. PKPs were most often performed for keratoconus (81.6%), post-LASIK ectasia (6.2%), pseudophakic bullous keratopathy (6.2%), corneal scarring (2%), pellucid marginal degeneration (2%), and hyperopia after radial keratotomy (2%). The refractive astigmatism (primary outcome) changed from 6.34 (0.35) to 3.67 (0.58) diopters following ICRS placement. Spherical error was reduced post-operatively to -1.87 (0.76) from a baseline of -4.43 (1.14) and Kmax was reduced from 52.30 (1.69) to 49.53 (2.26) diopters. BCVA improved post-procedure from a baseline of 0.53 (0.08) logMAR to 0.24 (0.03) logMAR. All changes were statistically significant (p<0.001). No significant adverse events were reported.
Conclusions
Our work suggests that ICRS placement is a safe and effective option for the management of residual astigmatism post-PKP.