目的 探索不同条件下角膜黏弹性在喷气试验中的作用。 方法 基于患者角膜地形图数据构建个性化全眼 模型,加载喷气模型,分析不同条件下线弹性和黏弹性角膜材料喷气试验结果的差异。 结果 在角膜刚度、眼内 压、巩膜刚度都相同的情况下,线弹性材料的角膜顶点最大位移比黏弹性材料小 0. 01 ~ 0. 03 mm;当角膜刚度和巩 膜刚度一定,眼内压从 12 mmHg 增大到 24 mmHg(1 mmHg = 0. 133 kPa)时,线弹性材料的角膜顶点最大位移绝对值 的下降速率比黏弹性材料慢 0. 9 μm/ mmHg;当角膜刚度和眼内压一定,巩膜刚度从 1. 24 MPa 变化到 9. 92 MPa 时, 线弹性材料的角膜顶点最大位移绝对值的下降速率比黏弹性材料慢 1. 1 μm/ MPa;当巩膜刚度和眼内压一定,角膜 刚度 0. 827 MPa 变化到 2. 790 MPa 时,线弹性材料的角膜顶点最大位移绝对值的下降速率比黏弹性材料慢 8 μm/ MPa。 结论 喷气试验中的角膜顶点位移主要由角膜组织的弹性驱动,角膜黏弹性在喷气试验中的作用不 明显。 在临床上采用喷气法评估角膜生物力学响应时,可忽略角膜黏弹性影响。
Objective To explore the role of corneal viscoelasticity on air-puff test under different conditions. Methods Based on the patient’ s corneal topographic data, the patient-specific model of the whole human eye was constructed, and the air-puff model was loaded. The differences in air-puff test results of linear elastic and viscoelastic corneal materials under different conditions were analyzed. Results When the corneal stiffness, intraocular pressure and scleral stiffness were all the same, the maximum corneal apical displacement of linear elastic material was 0. 01-0. 03 mm smaller than that of viscoelastic materials. With the intraocular pressure increasing from 12 mmHg to 24 mmHg ( 1 mmHg = 0. 133 kPa), the decreasing rate of the maximum corneal apical displacement of linear elastic materials was only 0. 9 μm / mmHg slower than that of viscoelastic material. With the corneal stiffness increasing from 0. 827 MPa to 2. 790 MPa, the decreasing rate of the maximum corneal apical displacement of linear elastic materials was only 8 μm / MPa slower than that of viscoelastic materials. With the scleral stiffness increasing from 1. 24 MPa to 9. 92 MPa, the decreasing rate of the maximum corneal apical displacement of linear elastic material was only 1. 1 μm / MPa slower than that of viscoelastic materials. Conclusions The corneal apical displacement in air-puff test was mainly driven by elasticity of the corneal tissues, but the role of corneal viscoelasticity in air-puff test was not obvious. The effect of corneal viscoelasticity can be ignored when air-puff method is used to evaluate the corneal biomechanical response.