Vellara Hans R, Patel Dipika V
Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
Clin Exp Optom. 2015 Jan;98(1):31-8. doi: 10.1111/cxo.12211.
There has been a recent surge of interest in assessing corneal biomechanical properties due to potential clinical applications, particularly in the early detection of keratoconus (KC). This review discusses the effects of keratoconus on the biomechanical properties of the cornea and the current techniques used to detect these changes both in the laboratory and clinical setting. Specific structural changes occurring in the corneal stroma as part of the disease process can be linked to alterations in the viscous and elastic properties of the cornea in keratoconus. Although there are extensive ex vivo studies using techniques such as extensometry and inflation testing to analyse the biomechanical properties of the normal cornea, few have investigated the keratoconic cornea using the same methods. There are a number of ex vivo studies that confirm the effectiveness of collagen cross-linking in increasing Young's modulus in healthy corneas. Recently, research has focussed on measuring corneal biomechanical parameters in vivo using two commercially available instruments: the Ocular Response Analyser (ORA) and the CorVis ST (CST). Both instruments analyse the dynamic behaviour of the cornea, when temporarily deformed by an air puff; however, the outputs of these instruments are not directly comparable due to differences in the characteristics of the air puff and output parameters. Studies using these instruments have reported significant differences between keratoconic and healthy corneas; however, neither instrument can currently be used in isolation to reliably diagnose keratoconus. Further research analysing the outputs of these instruments may enhance their diagnostic capabilities.
由于潜在的临床应用，尤其是在圆锥角膜（KC）的早期检测方面，最近对评估角膜生物力学特性的兴趣激增。本综述讨论了圆锥角膜对角膜生物力学特性的影响，以及目前在实验室和临床环境中用于检测这些变化的技术。作为疾病过程的一部分，角膜基质中发生的特定结构变化可能与圆锥角膜中角膜的粘性和弹性特性改变有关。尽管有大量使用拉伸测量和膨胀测试等技术的体外研究来分析正常角膜的生物力学特性，但很少有研究使用相同方法研究圆锥角膜。有许多体外研究证实了胶原交联在增加健康角膜杨氏模量方面的有效性。最近，研究集中在使用两种商用仪器在体内测量角膜生物力学参数：眼反应分析仪（ORA）和CorVis ST（CST）。两种仪器都分析角膜在被气流暂时变形时的动态行为；然而，由于气流特性和输出参数的差异，这些仪器的输出不能直接比较。使用这些仪器的研究报告了圆锥角膜和健康角膜之间的显著差异；然而，目前这两种仪器都不能单独用于可靠地诊断圆锥角膜。对这些仪器输出的进一步研究可能会提高它们的诊断能力。
