一种测量角膜弹性模量的新方法

为了在离体状态下采用完整的兔眼角膜,以一种新的方法测量角膜的弹性模量,并对比角膜切削后前凸位移和应力的变化.应用准分子激光切削兔眼角膜,改变角膜的厚度.剥离和固定角膜,在角膜内表面施加静水压力,三维扫描仪扫描和获取正常角膜厚度、切削原角膜厚度1/3和1/2角膜厚度的角膜图形,计算出各组角膜中心的前凸位移.Abaqus有限元软件建立相应的模型,利用实验得出的前凸位移反推兔眼角膜的弹性模量.结果表明反推得到兔眼角膜的弹性模量随角膜切削量的增加而增加.反推得到的弹性模量与临床检测一致,切削越多模型在切削区域表现为应力增大,在位移上反映为切削区域的位移量增加,但位移与应力在切削边界上都不发生突变.

A New Method Used to Measure Corneal Elastic Modulus

In vitro,a new method was used to measure corneal elastic modulus of an integrity rabbit cornea,and keratectomy protrusive displacement and stress changes were contrasted.In ex vivo to research biomechanical changes in the cornea of rabbits,excimer laser incision was performed in laser in situ keratomileusis.In the condition of hydrostatic pressure on the corneal inner surface,three corneas such as integrity,1/3 ablation and 1/2 ablation in thickness and 6 mm diameter in central regions were scanned,and the protusive displacement in different corneal centers was calculated.Using Abaqus finite element software to establish the corresponding models,the rabbit corneal elastic modulus with accessed protrusive displacement were calculated.Calculated rabbit corneal elastic modulus increases with increased keratectomy volume.The tendency of the elastic modulus is consistent with the clinical detection.The more stress and the more displacement is in the model of the thinner central region.The displacement and stress are not rapidly changing in ablation border.