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Corneal collagen cross-linking epi-on vs epi-off: a systematic review and meta-analysis

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First Author: F.D'Oria SPAIN

Co Author(s):    A. Palazon   J. Alio                 

Abstract Details

Purpose:

To determine, in an evidence-based manner and using the currently available literature, the advantages and disadvantages of epi-on corneal collagen cross-linking (CXL) techniques compare to traditional epi-off CXL and to discuss their indications. Therefore, we conducted a systematic review and meta-analysis to compare the effectiveness of these treatments.

Setting:

Vissum Innovation, Alicante, Spain.

Methods:

We searched MEDLINE and EMBASE for Randomized controlled Trials (RCTs) and Non-Randomized Studies of Interventions (NRSIs) and we evaluated the selected papers according to the Cochrane risk of bias tool and ROBIN-S, respectively. We considered, as primary outcomes, average Kmax flattening, changes in uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA). As secondary outcomes we analized changes in pachymetry values and endothelial cell density (ECD). Meta-analysis was conducted with a fixed or random-effects model using weighted mean difference (MD) with 95% confidence interval (CI) as the effect size. Heterogeneity was evaluated using the Q and I tests.

Results:

A total of 15 studies were included; among these 15 trials, 9 were RCTs and 6 were NRSIs, but only 4 studies showed no high risk of bias and were included in the meta-analysis. Our analysis revealed significative post-operative differences in CDVA (MD= 0.07; 95% CI= 0.04, 0.10; p<.001), and no significative differences in UDVA (MD=-0.03; 95% CI -0.09, 0.02; p=.228), Kmax (MD=-0.95; 95% CI -2.31, 0.42; p=.174), CCT (MD=-3.52; CI=-12.61, 5.58; p=.448) and ECD (MD=1.80; CI=-23.25, 26.86; p=.888).

Conclusions:

The published evidence indicates that, except for higher significant improvement in CDVA with current epi-on protocols, analysis of the limited number of comparative studies available seems to demonstrate that epi-off and epi-on CXL have a comparable effect on visual, topographic, pachymetric, and endothelial parameters.

Financial Disclosure:

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