Influence of corneal biomechanical properties on intraocular pressure measurement - Quantitative analysis
Influence of corneal biomechanical properties on intraocular pressure measurement - Quantitative analysis
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DOI：
10.1016/j.jcrs.2004.09.031
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发表时间：
2005-01-01
影响因子：
2.8
通讯作者：
Roberts, CJ
中科院分区：
文献类型：
--
作者：
Liu, J;Roberts, CJ
目的：利用角膜生物力学模型，了解和量化压平眼压测量中角膜变量引起的眼压测量误差。地点：美国俄亥俄州哥伦布市俄亥俄州立大学生物医学工程中心眼科。方法：该模型基于压平压力、真实IOP和泪膜引起的表面张力的总和假设一个总合力压力，以确定IOP测量时角膜顶点的最终变形。角膜阻力根据角膜的生物力学特性、厚度和曲率而变化，并定量检查每个变量对眼压测量读数准确性的影响。结果：该模型表明眼压读数并不总是反映真实的IOP值。当角膜的厚度、曲率或生物力学特性偏离正常值时，它们就会偏离。基于该模型，预测IOP读数的范围为2.87毫米汞柱，这是由于正常人群角膜厚度的变化，而角膜曲率半径的变化则为1.76毫米汞柱。考虑到正常人群中角膜的杨氏模量在0.1到0.9 MPa之间变化，该模型预测眼压计IOP读数的范围将为17.26 mm Hg，因为角膜生物力学参数本身存在变化。结论：基于模型的模拟定量地证明了每个角膜变量的变化会导致眼压测量读数的误差。模拟结果表明，个体间角膜生物力学的差异可能比角膜厚度或曲率对IOP测量误差的影响更大。
Purpose: To understand and quantify intraocular pressure (IOP) measurement errors introduced by corneal variables during applanation tonometry using a cornea biomechanical model.Setting: Department of Ophthalmology, Biomedical Engineering Center, The Ohio State University, Columbus, Ohio, USA.Methods: The model assumed an overall resultant pressure that was based on the summation of the applanation pressure, the true IOP, and the surface tension caused by the tear film to determine the final deformation of the corneal apex during IOP measurement. Corneal resistance was varied according to the cornea's biomechanical properties, thickness, and curvature, and the effect of each variable on the accuracy of IOP tonometry readings was examined quantitatively.Results: The model demonstrated that tonometry readings do not always reflect true IOP values. They deviate when corneal thickness, curvature, or biomechanical properties vary from normal values. Based on the model, predicted IOP readings have a 2.87 mm Hg range resulting from the variation in the corneal thickness in the normal population and a 1.76 mm Hg range from the variation in the corneal radius of curvature. Considering that Young's modulus of the corneal varies from 0.1 to 0.9 MPa in the normal population, the model predicts tonometry IOP readings will have a range of 17.26 mm Hg because of the variation in this corneal biomechanical parameter alone.Conclusions: The simulation based on the model demonstrated quantitatively that variations in each corneal variable cause errors in tonometry IOP readings. The simulation results indicate that differences in corneal biomechanics across individuals may have greater impact on IOP measurement errors than corneal thickness or curvature.