基于定量瞳孔阻滞力仿真实验的虹膜组织生物力学特性分析

An experiment research based on simulating pupillary blocking force to analyze mechanical properties of iris tissue quantitatively

目的分析瞳孔阻滞力作用下的虹膜特性,探讨虹膜生物力学特性参量与瞳孔阻滞力和前后房压强差的关系。方法利用设计的瞳孔阻滞力仿真装置模拟瞳孔阻滞力,用液体加压装置模拟前后房压强差,对实验动物的虹膜进行整体加压,定量分析瞳孔阻滞力作用下的虹膜面应变、曲率半径的变化与前后房压强差的关系,以及不同大小的瞳孔阻滞力与前后房压强差的关系。结果获得了与临床现象相近的实验模型,与前期实验工作的方法相比,该实验方法更接近生理状态。得出分别以面应变、虹膜膨隆最高点的曲率半径与前后房压强差关系表达的方程,虹膜面应变δ与前后房压强差ΔP成以下规律:ΔP=b0eb1δ(b0=3.3373,b1=30.3909);虹膜曲率半径r与前后房压强差ΔP关系:r=e(b0+b1/ΔP)(b0=0.4761,b1=21.6604)。初步完成了虹膜特性和瞳孔阻滞力的定量研究,描述了不同大小的瞳孔阻滞力与前后房压强差的关系。结论实现了软组织小力学量的定量测量。面应变和曲率半径是可量化的虹膜形变特性参量,能够敏感的反映前后房压强差的变化,虹膜膨隆最高点的曲率半径是临床上容易测量的指标,对其的测量将帮助人们更好的进行早期临床诊断和治疗。

Objective To analyze the mechanical properties of iris tissue based on stimulating puptllary blocking force in order to find the relation between the parameter of the iris property and the differential pressure between the anterior and posterior chamber, Methods We applied simulating pupillary blocking device to simulate the pupillary blocking force and used liquid loading apparatus to simulate the differential pressure between the anterior and posterior chamber. Then we loaded pressure on the integrative iris to quantitatively analyze the relationship between the pressure of the anterior and posterior chamber with the change of the strain of iris surface and the radius of iris curvature under the pupillary blocking force. Results The model was similar with the clinical phenomena. This model was more true to nature than the model that we sutured the pupil before. Using the model, we gained the equation containing the strain of iris surface（δ）, the radius of iris curvature（ r ） and the differential pressure between the anterior and posterior chamber（ΔP）. The equation of δ and ΔP was ΔP = boeb1δ（ b0 = 3. 337 3, b1 = 30.390 9）. The equation of r and ΔP was r = e（b0＋b1/Δp） （b0 = 0. 476 1, b1 = 21.660 43）. We realized the quantitative analysis and described the relationship between the different pupillary blocking force and the differential pressure between the anterior and posterior chamber. Conclusion We realize the quantitative measurement for small dynamic parameter of soft tissue. The strain of surface and the radius of curvature of the iris is the property parameter that can be measured. They can reflect the change of the differential pressure between the anterior and posterior chamber sensitively. The radius of curvature of the highest spot of the iris can be measured easily in clinic. So it can help us diagnose and treat the glaucoma early.