Lamellar orientation in human cornea in relation to mechanical properties
Lamellar orientation in human cornea in relation to mechanical properties
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DOI：
10.1016/j.jsb.2004.08.009
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发表时间：
2005-01-01
影响因子：
3
通讯作者：
Meek, KM
中科院分区：
文献类型：
--
作者：
Boote, C;Dennis, S;Meek, KM
我们将广角x射线散射应用于人类角膜，以量化沿两个首选角膜板层方向（上-下和鼻-颞）的基质胶原原纤维的相对数量。数据证明了这一点。平均而言，这两个方向在角膜中心的分布比例相等。在这里，大约三分之一的原纤维分布在上下经络的45扇形内，鼻颞方向也是如此。然而，在一些眼睛中，我们测量了两种优先纤维群之间的显著差异，一些角膜在一个方向上的胶原蛋白比另一个方向多25%。基于这些发现，可以设想一个正常角膜的力学模型，其中各向同性排列的胶原蛋白的潜在“背景”中的纤维张力有助于平衡眼内压：而额外优先排列的原纤维则承担由直肌和轮匝肌施加的沿上-下和鼻-颞经的额外拉伸应力。这是可能的，通过直接影响组织的弹性模量，不平衡的上-下和鼻-颞原纤维在某些眼睛可能会影响角膜形状。(C) 2004爱思唯尔公司版权所有。
We have applied wide-angle X-ray scattering to the human cornea in order to quantify the relative number of stromal collagen fibrils directed along the two preferred corneal lamellar directions: superior-inferior and nasal-temporal. The data sue-est that. on average, the two directions are populated in equal proportion at the corneal centre. Here, approximately one-third of the fibrils throughout the stromal depth tend to lie within a 45 sector of the superior-inferior meridian, and similarly for the nasal-temporal direction. However, in some eyes we have measured significant differences between the two preferential fibril populations with some corneas exhibiting as much as 25% more collagen in one direction than the other. Based on these findings, a mechanical model of the normal cornea may be envisaged, whereby the fibril tension in the underlying "background" of isotropically arranged collagen helps to balance the intraocular pressure: while the extra preferentially aligned fibrils take up the additional tensile stress along the superior-inferior and nasal-temporal meridians exerted by the rectus muscles and the orbicularis. It is possible that, through a direct impact on the elastic modulus of the tissue, an imbalance Of superior-inferior and nasal-temporal fibrils in some eyes might affect corneal shape. (C) 2004 Elsevier Inc. All rights reserved.