Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong.
Hong Kong Eye Hospital, Kowloon, Hong Kong.
Clin Exp Ophthalmol. 2021 Apr;49(3):228-241. doi: 10.1111/ceo.13918. Epub 2021 Mar 18.
Standard epithelium-off collagen cross-linking using Dresden protocol (S-CXL) is the standard of care for progressive keratoconus. Despite its efficacy, epithelial debridement is associated with pain, delayed visual rehabilitation, stromal oedema and haze. Minimising these complications while achieving a comparable efficacy remains an unmet need.
Comparative studies between transepithelial iontophoresis-assisted CXL (I-CXL) and S-CXL reporting the outcomes of visual, refractive, topographic, aberrometry, demarcation line, endothelial cell density, confocal microscopy or complications were identified from databases. Assessments of publication bias, meta-analyses, sensitivity analysis, subgroup analysis, and meta-regressions were performed.
In this meta-analysis, 586 eyes from three randomised controlled trials and seven comparative studies were analysed. No differences were found in the change in uncorrected/corrected distance visual acuities, mean/maximum keratometry, central corneal thickness, higher order aberration, spherical aberration, coma, subbasal nerve/anterior stromal keratocyte density and demarcation line depth in both CXL protocols (P ≥ .052). However, I-CXL resulted in less thinning at the minimum pachymetry (standardised mean difference 0.25; 95% confidence interval [CI] 0.06-0.44). More importantly, there was a significant reduction in complications following I-CXL (odds ratio 0.30; 95% CI 0.12-0.75). Meta-regression analyses on demarcation line depth and complication suggested that I-CXL was more effective than S-CXL when baseline maximum keratometry was >55.2 D and the risk of complication was independent of other baseline covariates.
I-CXL has a more favourable safety profile, as evidenced by the available literature, with less thinning at the minimum pachymetry and reduced risk of complications while achieving comparable effects on visual, refractive, topographic, aberrometry, and morphological outcomes as S-CXL.
采用德累斯顿方案的标准上皮去除胶原交联术（S-CXL）是进行进行性圆锥角膜治疗的标准方法。尽管该方法有效，但上皮清创术会引起疼痛、视力恢复延迟、基质水肿和混浊。在实现类似疗效的同时，尽量减少这些并发症仍然是一个未满足的需求。
从数据库中确定了比较经上皮离子电渗辅助交联术（I-CXL）与 S-CXL 的对照研究，这些研究报告了视力、屈光、地形、像差、分界线、内皮细胞密度、共聚焦显微镜或并发症的结果。进行了发表偏倚评估、荟萃分析、敏感性分析、亚组分析和荟萃回归分析。
在这项荟萃分析中，对来自三项随机对照试验和七项对照研究的 586 只眼进行了分析。两种 CXL 方案在未矫正/矫正距离视力、平均/最大角膜曲率、中央角膜厚度、高阶像差、球差、慧差、基底神经纤维/前基质角膜细胞密度和分界线深度的变化上没有差异（P≥.052）。然而，I-CXL 导致的最小角膜厚度变薄程度较小（标准化均数差 0.25；95%置信区间 [CI] 0.06-0.44）。更重要的是，I-CXL 后并发症显著减少（比值比 0.30；95%CI 0.12-0.75）。对分界线深度和并发症的荟萃回归分析表明，当基线最大角膜曲率 >55.2 D 时，I-CXL 比 S-CXL 更有效，而并发症的风险与其他基线协变量无关。
根据现有文献，I-CXL 具有更有利的安全性，在最小角膜厚度变薄程度较小和减少并发症风险的同时，在视力、屈光、地形、像差和形态学结果方面达到与 S-CXL 相当的效果。
