Inverse computational analysis of in vivo corneal elastic modulus change after collagen crosslinking for keratoconus
Inverse computational analysis of in vivo corneal elastic modulus change after collagen crosslinking for keratoconus
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DOI：
10.1016/j.exer.2013.04.010
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发表时间：
2013-08-01
影响因子：
3.4
通讯作者：
Dupps, William J., Jr.
中科院分区：
文献类型：
--
作者：
Roy, Abhijit Sinha;Rocha, Karol M.;Dupps, William J., Jr.
角膜胶原交联与核黄素光敏化和紫外线照射是一种新的方法，以限制患者的圆锥角膜的进展，通过增加退化的角膜的弹性模量。交联后角膜陡度和像差的有益降低也经常发生。在以前的研究中，我们描述了一种计算建模方法来模拟圆锥角膜的地形图进展和角膜胶原交联疾病的消退。在目前的研究中，该模型已被扩展，并应用于逆问题的估计纵向时间依赖性变化的角膜弹性模量交联后，使用体内测量16人的眼睛。交联前测量的地形图用于构建具有假定超弹性特性的患者特定有限元模型。然后使用逆优化方法改变角膜的性质，以最小化交联后模型预测和体内角膜形状之间的差异。还研究了关于巩膜-角膜弹性模量比和治疗效果的空间衰减的假设对弹性模量预测变化的影响。通过逆向有限元分析计算的角膜特性变化与交联后患者眼睛的临床地形测量结果具有极好的几何一致性。在所有治疗后时间点，角膜弹性模量的估计增加为110.8 +/-48.1%，并且当巩膜-角膜模量比增加时，需要稍微较少的硬化来产生相同量的疾病角膜地形图回归。包括光束衰减的影响导致前角膜硬化的估计值更大。角膜形状对交联的反应差异很大，强调了患者特异性方法的重要性。(C)2013爱思唯尔有限公司保留所有权利。
Corneal collagen crosslinking with riboflavin photosensitization and ultraviolet irradiation is a novel approach to limiting the progression of keratoconus in patients by increasing the elastic modulus of the degenerate cornea. Beneficial reductions in corneal steepness and aberrations after crosslinking also frequently occur. In a previous study, we described a computational modeling approach to simulating topographic progression in keratoconus and regression of disease with corneal collagen crosslinking. In the current study, this model has been expanded and applied to the inverse problem of estimating longitudinal time-dependent changes in the corneal elastic modulus after crosslinking using in vivo measurements from 16 human eyes. Topography measured before crosslinking was used to construct a patient-specific finite element model with assumed hyperelastic properties. Then the properties of the cornea were altered using an inverse optimization method to minimize the difference between the model-predicted and in vivo corneal shape after crosslinking. Effects of assumptions regarding sclera-to-cornea elastic modulus ratio and spatial attenuation of treatment effect due to ultraviolet beam characteristics on the predicted change in elastic modulus were also investigated. Corneal property changes computed by inverse finite element analysis provided excellent geometric agreement with clinical topography measurements in patient eyes post-crosslinking. Over all post-treatment time points, the estimated increase in corneal elastic modulus was 110.8 +/- 48.1%, and slightly less stiffening was required to produce the same amount of corneal topographic regression of disease when the sclera-to-cornea modulus ratio was increased. Including the effect of beam attenuation resulted in greater estimates of stiffening in the anterior cornea. Corneal shape responses to crosslinking varied considerably and emphasize the importance of a patient-specific approach. (C) 2013 Elsevier Ltd. All rights reserved.