AGING OF HUMAN CRYSTALLINE LENS DYNAMICS

这项研究的主要目标是定量地描述 人的调节机制与年龄相关性调节损失 (老花眼)成人正视眼。通融的过程，通过这个过程 人眼聚焦于附近的物体，通过受控的变化发生在 水晶透镜的形状。一般认为，作为纤毛， 肌肉收缩时，晶状体会经历弹性或粘弹性 松弛导致沿极轴的厚度增加， 前房变浅，并沿前房厚度增加 晶状体前后表面的曲率；后两者 事件起到了增加地球整体折射能力的作用。使用 随着年龄的增长，调节幅度降低，以至于近点 逐渐消退，导致一般到50岁时需要 光学假体。这种年龄相关性退化的原因 调节范围被不同程度地归因于 睫状肌，晶体晶体的生长和/或硬化， 玻璃体液化和几何关系的变化 晶状体和睫状肌之间通过小带。我们计划使用 我们收集了149名成人正视眼受试者的数据 年龄为18岁和70岁，其中包括厚度测量的结果， 角膜曲率计、超声波和Scheimpflg裂隙灯摄影，以 描述人眼的老化，特别是晶状体，以及 调节过程与老花眼的发展。统计 对这些数据的分析将使我们能够识别和描述 年龄相关参数与独立参数之间的相互作用 住宿。透镜弹性特性的同时表征 使用新鲜的死后人类晶状体将直接检验 镜片随着年龄的增长而变硬。这些数据将用于以下应用 用于老年人衰老研究的两种新的计算机住宿模型 晶状体相关结构的调节过程及其作用 这一过程。这些数据也可以用来研究--最终 解决--“镜头悖论”。

The primary goal of this research is to characterize quantitatively the mechanism of human accommodation and age-dependent accommodative loss (presbyopia) in adult emmetropes. Accommodation, the process by which the human eye focuses on near objects, occurs through controlled changes in the shape of the crystalline lens. It is generally held that, as the ciliary muscle contracts, the lens goes through an elastic or visoelastic relaxation that results in an increased thickness along the polar axis, a shallowing of the anterior chamber, and increased thickness along the curvature on the anterior and posterior lens surfaces; the latter two events act to increase the overall refractive power of the globe. With increasing age, accommodative amplitude decreases such that the near point gradually recedes, leading generally by the age of 50 yr to the need for optical prostheses. The causes of this age-dependent degradation of accommodative range have been attributed variously to degeneration of the ciliary muscle, growth and/or hardening of the crystalline lens, liquefication of the vitreous, and changes in the geometric relationship between the lens and ciliary muscles through the zonules. We plan to use the data we have collected on 149 adult emmetropic human subjects between the ages of 18 and 70 yr, which includes results from pachymetry, keratometry, ultrasonography, and Scheimpflug slit-lamp photography, to characterize the aging of the human eye, especially the lens, and both the process of accommodation and the development of presbyopia. Statistical analysis of these data will allow identification and characterization of the interaction of age-dependent and -independent parameters in accommodation. Concurrent characterization of lens elastic properties using fresh post-mortem human lenses will directly test the hypothesis of lens stiffening with age. These data will be used in the application of two new computer-based accommodation models to the study of the aging of the accommodation process and the roles of lens-associated structures in this process. These data can also be used to study - and eventually resolve - the "lens paradox".