Determination of Corneal Biomechanical Properties in vivo

体内角膜生物力学特性的测定

• 批准号: EP/H052046/1
• 负责人: Ahmed Elsheikh
• 金额: $ 50.64万
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FH052046%2F1
• 关键词: Determination; Corneal; Biomechanical; Properties; vivo

Despite recent advances in our understanding of corneal structure and the methods used to test corneal tissue in the lab, it is still impossible to measure corneal properties in-vivo. The inability to determine the basic biomechanical properties (such as hyperelasticity, hysteresis and viscoelasticity) in-vivo had a serious adverse effect on our ability to optimise treatments or predict their outcome, and made it necessary to rely on average properties obtained ex-vivo.This project aims to make in-vivo measurement of corneal biomechanical properties a reality. It seeks to cover the research needs underpinning the development of this technology and address two fundamental questions that have prevented progress in this field. The two questions revolve around the extraction of the material's stress-strain behaviour from the overall cornea's response to mechanical actions. Once these obstacles are removed, the path to establish in-vivo measurement technology becomes straightforward.There are significant potential benefits that can be achieved if corneal biomechanical properties could be measured in-vivo. The examples include better design of implants to restore clear vision in keratoconus patients, better planning of refractive surgery procedures that currently result in unexpected aberrations in 1:7 of patients, and the ability to eliminate effect of corneal stiffness on intraocular pressure measurements, which are required for glaucoma management. These potential developments will mean significant benefits to patients, healthcare services and medical device manufacturers.The research starts with an experimental study to determine the regional variation of corneal and scleral hyperelasticity, hysteresis and viscoelasticity. The study will use 3D digital imaging of human eye globes subjected to cycles of both intraocular pressure and external applanation forces and aim to address the key gaps in knowledge in ocular biomechanics.With maps of biomechanical properties established, numerical analysis tools will be built to embody these maps, in addition to existing knowledge on the biomechanical, topographic and micro-structural characteristics of the human eye. The tools, which will be custom built, will be validated against ocular behaviour data obtained experimentally before using them to develop conceptual techniques to measure corneal biomechanics in-vivo.Two types of property measurement techniques, based on contact and non-contact methods, will be assessed. In both cases, corneal response to a mechanical action is correlated to corneal stress-strain behaviour. This exercise will focus on the key research questions, and aim to formalise an analysis procedure to extract the cornea's stress-strain behaviour from its mechanical response, and to exclude the effects of intraocular pressure and cornea's geometric parameters on the results.The results of the numerical study will be assessed using proof-of-concept prototypes both experimentally on human eye globes and on volunteers within a clinical setting. The tests are intended to validate the numerical findings, cast light onto the characteristics of ocular deformation under mechanical actions, and provide initial results which will be important for the conduct of future clinical studies on fully operational device prototypes.Overall, the project addresses a challenging problem that is affecting progress in several areas of patient care in ophthalmology. It seeks to overcome the main barriers to making the in-vivo measurement of corneal properties a reality. The project follows a systematic approach where necessary knowledge about ocular behaviour is generated and a predictive tool of ocular mechanical response built before assessing the property measurement methods. With the knowledge and understanding to be generated in this project, research and development can progress to embody the new technology into medical devices suitable for clinical use.

尽管我们对角膜结构的理解以及在实验室中测试角膜组织的方法最近取得了进展，但仍然不可能在体内测量角膜特性。无法确定体内的基本生物力学特性（例如超弹性、滞后和粘弹性）对我们优化治疗或预测其结果的能力产生了严重的不利影响，并且使得必须依赖体外获得的平均特性。该项目旨在使角膜生物力学特性的体内测量成为现实。它旨在满足支持该技术发展的研究需求，并解决阻碍该领域取得进展的两个基本问题。这两个问题围绕着从角膜对机械作用的整体响应中提取材料的应力应变行为。一旦这些障碍被消除，建立体内测量技术的道路就变得简单了。如果可以在体内测量角膜生物力学特性，那么可以实现显着的潜在好处。这些例子包括更好地设计植入物以恢复圆锥角膜患者的清晰视力，更好地规划屈光手术程序（目前导致1:7的患者出现意外像差），以及消除角膜硬度对眼压测量的影响的能力，这是青光眼治疗所需的。这些潜在的发展将对患者、医疗保健服务和医疗设备制造商意味着重大利益。该研究从一项实验研究开始，以确定角膜和巩膜超弹性、滞后和粘弹性的区域变化。该研究将使用受到眼内压和外部压平力循环影响的人眼眼球的3D数字成像，旨在解决眼生物力学知识中的关键差距。随着生物力学特性图的建立，除了关于人眼生物力学、地形和微观结构特征的现有知识之外，还将建立数值分析工具来体现这些图。这些定制工具将根据实验获得的眼部行为数据进行验证，然后再使用它们开发测量体内角膜生物力学的概念技术。将评估基于接触式和非接触式方法的两种类型的属性测量技术。在这两种情况下，角膜对机械作用的反应与角膜应力应变行为相关。本次练习将重点关注关键研究问题，旨在形式化分析程序，从角膜的机械响应中提取角膜的应力应变行为，并排除眼压和角膜几何参数对结果的影响。数值研究的结果将使用概念验证原型在人眼眼球和临床环境中的志愿者身上进行评估。这些测试旨在验证数值结果，揭示机械作用下眼睛变形的特征，并提供初步结果，这对于未来对完全可操作的设备原型进行临床研究非常重要。总体而言，该项目解决了一个具有挑战性的问题，该问题正在影响眼科患者护理多个领域的进展。它致力于克服主要障碍，使角膜特性的体内测量成为现实。该项目遵循系统方法，在评估特性测量方法之前生成有关眼部行为的必要知识并构建眼部机械反应的预测工具。凭借该项目中产生的知识和理解，研究和开发可以取得进展，将新技术体现到适合临床使用的医疗设备中。

项目成果

Understanding corneal biomechanics through experimental assessment and numerical simulation

通过实验评估和数值模拟了解角膜生物力学

• 发表时间: 2011
• 期刊: Principles, Trends and Applications
• 作者: Elsheikh A.

Consideration of corneal biomechanics in the diagnosis and management of keratoconus: is it important?

• DOI: 10.1186/s40662-016-0048-4
• 发表时间: 2016
• 期刊: Eye and vision (London, England)
• 作者: Bao F;Geraghty B;Wang Q;Elsheikh A
• 通讯作者: Elsheikh A

Evaluation of the shape symmetry of bilateral normal corneas in a Chinese population.

• DOI: 10.1371/journal.pone.0073412
• 发表时间: 2013
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Bao F;Chen H;Yu Y;Yu J;Zhou S;Wang J;Wang Q;Elsheikh A
• 通讯作者: Elsheikh A

Is scleral cross-linking a feasible treatment for myopia control?

• DOI: 10.1111/opo.12043
• 发表时间: 2013-05-01
• 期刊: OPHTHALMIC AND PHYSIOLOGICAL OPTICS
• 影响因子: 2.9
• 作者: Elsheikh, A.;Phillips, J. R.
• 通讯作者: Phillips, J. R.