Howland H C, Rand R H, Lubkin S R
Section of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853.
Refract Corneal Surg. 1992 Mar-Apr;8(2):183-6.
We present a thin-shell, analytical model of the vertebrate cornea to study the changes in shape resulting from surgical operations (eg, radial keratotomy).
A simple closed-form solution is derived for a thin linearly elastic spherical model of the cornea. We assume that the shell is symmetrical about a central axis and that the modulus of elasticity is the same in all directions. The surgery is modeled by allowing the modulus of elasticity (or equivalently the thickness) of the shell to depend upon position, measured as an angle from the axis of symmetry.
The analytical nature of the solution allows us to compute the principal curvatures of the cornea explicitly. For example, for representative parameters, the model predicts the average corneal curvature changes from about 43 diopters before keratotomy to about 38 D after keratotomy.
The model is used to estimate Young's modulus from experimental data reported previously by Thomas et al (Invest Ophthalmol Vis Sci 1991;32:1000), as well as to investigate the effect of surgery on corneal flattening and the associated sensitivity to intraocular pressure changes.
我们提出了一种脊椎动物角膜的薄壳分析模型，以研究手术操作（如放射状角膜切开术）引起的形状变化。
为角膜的薄线性弹性球形模型推导了一个简单的封闭形式解。我们假设壳关于中心轴对称，并且弹性模量在所有方向上相同。通过允许壳的弹性模量（或等效地厚度）取决于从对称轴测量的角度来模拟手术。
解的解析性质使我们能够明确计算角膜的主曲率。例如，对于代表性参数，该模型预测角膜曲率平均值从角膜切开术前约43屈光度变为角膜切开术后约38 D。
该模型用于根据Thomas等人先前报道的实验数据（Invest Ophthalmol Vis Sci 1991;32:1000）估计杨氏模量，以及研究手术对角膜变平的影响以及对眼压变化的相关敏感性。
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