Redaelli Elena, Calvo Begoña, Rodriguez Matas Jose Felix, Luraghi Giulia, Grasa Jorge
Aragón Institute of Engineering Research (I3A), Universidad de Zaragoza, Zaragoza, Spain.
Centro de Investigación Biomecánica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Zaragoza, Spain.
Front Bioeng Biotechnol. 2024 Jul 25;12:1406870. doi: 10.3389/fbioe.2024.1406870. eCollection 2024.
Glaucoma, a leading cause of blindness worldwide, is primarily caused by elevated intraocular pressure (IOP). Accurate and reliable IOP measurements are the key to diagnose the pathology in time and to provide for effective treatment strategies. The currently available methods for measuring IOP include contact and non contact tonometers (NCT), which estimate IOP based on the corneal deformation caused by an external load, that in the case of NCT is an air pulse. The deformation of the cornea during the tonometry is the result of the coupling between the IOP, the mechanical properties of the corneal tissue, the corneal thickness, and the external force applied. Therefore, there is the need to decouple the four contributions to estimate the IOP more reliably. This paper aims to propose a new methodology to estimate the IOP based on the analysis of the mechanical work performed by the air jet and by the IOP during the NCT test. A numerical eye model is presented, initially deformed by the action of a falling mass to study the energy balance. Subsequently, Fluid-Structure Interaction (FSI) simulations are conducted to simulate the action of Corvis ST. The new IOP estimation procedure is proposed based on the results of the simulations. The methodology is centred on the analysis of the time of maximum apex velocity rather than the point of first applanation leading to a new IOP estimation not influenced by the geometrical and mechanical corneal factors.
青光眼是全球失明的主要原因之一，主要由眼内压（IOP）升高引起。准确可靠的眼压测量是及时诊断病情并提供有效治疗策略的关键。目前可用的眼压测量方法包括接触式和非接触式眼压计（NCT），它们基于外部负荷引起的角膜变形来估计眼压，在非接触式眼压计的情况下，外部负荷是一个空气脉冲。眼压测量过程中角膜的变形是眼压、角膜组织的力学性能、角膜厚度和施加的外力之间耦合的结果。因此，需要将这四种因素解耦，以便更可靠地估计眼压。本文旨在提出一种基于分析非接触式眼压计测试过程中空气喷射和眼压所做机械功来估计眼压的新方法。提出了一个数值眼模型，最初通过落体的作用使其变形以研究能量平衡。随后，进行流固耦合（FSI）模拟以模拟Corvis ST的作用。基于模拟结果提出了新的眼压估计程序。该方法的核心是分析最大顶点速度的时间，而不是首次压平点，从而得到一种不受角膜几何和力学因素影响的新眼压估计方法。
