Multiscale Modeling of Accommodation and Presbyopia

描述（由申请人提供）：数学建模可以提供对机制或过程的洞察，并且可以用来做出可以通过实验测试的预测。这项工作的长期目标是建立一个多尺度模型，以增加对人类聚焦机制（调节）和与年龄相关的调节范围丧失（老花眼）的理解。老花眼是一个多因素的过程，其机制仍然是争议和分歧的主题，正如适应机制本身一样。了解老花眼是如何发展的，可能最终会找到减缓或停止这一过程的策略。更重要的是开发新的人工晶状体植入设计，利用眼睛独特的聚焦系统来恢复可调节的振幅。这项高级研究金提案的假设是，目前在文献中可以获得了解人类适应机制所需的大部分或全部信息，但没有组织形式。这个长期目标被分解为三个具体目标。目标1是创建一个更新和扩展的人体调节中晶状体和睫状肌的分析生物力学模型，使用定义良好的应变张量元素作为逆计算的基础，导致牵引力和力的增量变化与折射的增量变化。该模型将由使用相同数据集和假设的有限元表示加以补充。目标2是创建一个更新和扩展的图像形成的眼睛模型，使用近轴和非近轴光线追踪方法来测试当前和理论的想法关于折射率梯度的形状。这将用于将光学功能与晶状体表面和内部形状的生物力学变化联系起来。目标3将关注由晶状体结构组织和超微结构产生的生物力学和光学限制，并将成为连接晶状体纤维细胞的分子和大分子特性与晶状体调节功能的桥梁。老花眼是40岁及以上人群中最常见的视力障碍，据美国国家眼科研究所称，“对社会造成了巨大的经济损失”。聚焦过程随着年龄的增长而变化的方式可以为阻止或减缓视觉范围的丧失提供线索。在人工晶状体植入物的设计中，如何有效地恢复聚焦能力也很重要。

DESCRIPTION (provided by applicant): Mathematical modeling can provide insight into a mechanism or process, and can be used to make predications that can be tested experimentally. The long-term goal of the proposed work is to develop a multiscale model that will increase understanding of the human focusing mechanism (accommodation) and the age-related loss of accommodative range (presbyopia). Presbyopia is a multifactorial process, the mechanism of which remains the subject of controversy and disagreement, as does the accommodation mechanism itself. Understanding how presbyopia develops may ultimately lead to strategies for slowing or stopping the process. It is even more important in developing new designs for intraocular lens implants that can take advantage of the eye's unique focusing system to restore a measure of accommodative amplitude. It is the hypothesis of this senior fellowship proposal that most or all of the information necessary to understand the human accommodation mechanism is currently available in the literature, but not in an organized form. This long-term goal has been broken down into three specific aims. Aim 1 is to create an updated and expanded analytic biomechanical model of the crystalline lens and ciliary muscle in human accommodation, using well-defined strain tensor elements as the basis for inverse calculations leading to the incremental change in tractions and forces with an incremental change in refraction. This model will be complemented by a finite element representation using the same data sets and assumptions. Aim 2 is to create an updated and expanded model of image formation by the eye, using paraxial and non-paraxial ray- tracing approaches to test current and theoretical ideas about the shape of the refractive index gradient. This will be used to correlate optical function with biomechanical changes in lens shape, both on the surface and internally. Aim 3 will be concerned with the biomechanical and optical constraints created by crystalline lens structural organization and ultrastructure, and will be the bridge linking the molecular and macromolecular properties of the lens fiber cells with lens function in accommodation. Presbyopia is the most common visual disorder of people aged 40 and over, and, according to the National Eye Institute, "represents a significant economic cost to society". The way that the focusing process changes with aging can provide clues for ways to arrest or slow the loss of visual range. It is also important in the design of intraocular lens implants that can effectively restore focusing ability.