Changes in the biomechanical and biochemical properties of the human cornea play an important role in the pathogenesis of ectatic diseases. A number of conditions in primarily acquired (keratoconus or pellucid marginal degeneration) or secondarily induced (iatrogenic keratectasia after refractive laser surgeries) ectatic disorders lead to decreased biomechanical stability. Corneal collagen cross-linking (CXL) represents a technique to slow or even halt the progression of ectatic pathologies. In this procedure, riboflavin is applied in combination with ultraviolet A radiation. This interaction induces the production of reactive oxygen species, which leads to the formation of additional covalent bonds between collagen molecules and subsequent biomechanical corneal strengthening. This procedure is so far the only method that partially interferes etiopathogenetically in the treatment of ectatic diseases that slows or stops the process of corneal destabilization, otherwise leading to the need for corneal transplantation. Besides, CXL process increases markedly resistance of collagenous matrix against digesting enzymes supporting its use in the treatment of corneal ulcers. Since the discovery of this therapeutic procedure and the first laboratory experiments, which confirmed the validity of this method, and the first clinical studies that proved the effectiveness and safety of the technique, it has been spread and adopted worldwide, even with further modifications. Making use of the Bunsen-Roscoe photochemical law it was possible to shorten the duration of this procedure in accelerated CXL and thus improve the clinical workflow and patient compliance while maintaining the efficacy and safety of the procedure. The indication spectrum of CXL can be further expanded by combining it with other vision-enhancing procedures such as individualized topographically-guided excimer ablation. Complementing both techniques will allow a patient with a biomechanically stable cornea to regularize it and improve visual acuity without the need for tissue transplantation, leading to a long-term improvement in quality of life.

中文翻译：

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UV-A 和核黄素交联治疗渐进性圆锥角膜：从实验室到临床实践 – 25 年来的发展


人类角膜生物力学和生化特性的变化在扩张性疾病的发病机制中发挥着重要作用。原发性（圆锥角膜或透明边缘变性）或继发性（屈光激光手术后医源性角膜扩张）扩张性疾病中的许多情况会导致生物力学稳定性下降。角膜胶原交联（CXL）是一种减缓甚至阻止扩张性病变进展的技术。在此过程中，核黄素与紫外线 A 辐射结合使用。这种相互作用会诱导活性氧的产生，从而导致胶原蛋白分子之间形成额外的共价键，并随后强化角膜的生物力学。迄今为止，该手术是唯一在病因病理学上部分干扰扩张性疾病治疗的方法，可减缓或停止角膜不稳定的过程，否则将导致需要角膜移植。此外，CXL 工艺显着增加了胶原基质对消化酶的抵抗力，支持其用于治疗角膜溃疡。自从这种治疗方法的发现和首次实验室实验证实了该方法的有效性，以及首次临床研究证明了该技术的有效性和安全性以来，它已在全世界范围内传播和采用，甚至还进行了进一步的修改。利用本生-罗斯光化学定律，可以缩短加速 CXL 手术的持续时间，从而改善临床工作流程和患者依从性，同时保持手术的有效性和安全性。 通过将 CXL 与其他视力增强手术（例如个性化地形引导准分子消融术）相结合，可以进一步扩大 CXL 的适应范围。这两种技术的互补将使具有生物力学稳定角膜的患者能够对其进行调节并提高视力，而无需进行组织移植，从而长期改善生活质量。