Transepithelial versus epithelium-off corneal collagen cross-linking for corneal ectasia: a systematic review and meta-analysis
- Additional Document Info
- View All
TOPIC: To evaluate the safety and efficacy of transepithelial corneal cross-linking (CXL) in comparison to the established epithelium-off technique for corneal ectasia. CLINICAL RELEVANCE: There is considerable debate whether transepithelial and epithelium-off CXL are comparable in their safety and efficacy. METHODS: We searched 16 electronic databases including Medline, Embase, and Web of Science and the grey literature, current to July 8, 2020 for randomized controlled trials (RCTs) comparing transepithelial and epithelium-off CXL for corneal ectasia. We excluded studies evaluating CXL for non-ectatic indications, as well as non-RCTs. Our primary outcome was the change in maximal keratometry (Kmax) at 12 months following CXL and we considered additional topographic, visual, and safety outcomes. We summarized our analyses by calculating weighted mean differences (MDs) with associated 95% confidence intervals (CIs) for continuous outcomes and relative risks (RRs) with corresponding 95% CIs for dichotomous outcomes. We conducted trial sequential analysis (TSA) to determine whether the required information size was met for each outcome. The quality of individual trials was evaluated using the Cochrane Collaboration's risk of bias assessment tool and the evidence was assessed at an outcome-level using the grading of recommendations assessment, development, and evaluation (GRADE) methodology. RESULTS: 12 studies totaling 966 eyes were eligible. There was a significant difference between transepithelial and epithelium-off CXL groups in the change in Kmax at 12 months (MD 0.75, 95% CI 0.23-1.28, p=0.004; primary outcome) and at longest follow-up (MD 1.20, 95% CI 0.62-1.77, p<0.001; secondary outcome) after treatment. There was no significant difference between the two groups when examining uncorrected distance visual acuity (MD 0.04, 95% CI -0.06-0.14, p=0.386), or corrected distance visual acuity (MD 0.01, 95% CI -0.06-0.09, p=0.732). Transepithelial CXL was associated with significantly fewer complications than the epithelium-off approach (RR 0.22, 95% CI 0.06-0.79, p=0.020), although it was associated with an increased rate of disease progression at 12 months after treatment (RR 4.49, 95% CI 1.24-16.25, p=0.022). The required information size was met for our primary outcome and TSA supported the conventional meta-analysis. The quality of evidence was rated as moderate using the GRADE methodology. CONCLUSIONS: The efficacy of transepithelial CXL remains inferior to the epithelium-off approach, although it is significantly safer.
has subject area
presented at event