The physiological optics of the lens.
The physiological optics of the lens.
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DOI：
10.1016/j.preteyeres.2016.09.002
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发表时间：
2017-01-01
影响因子：
17.8
通讯作者：
Vaghefi, Ehsan
中科院分区：
文献类型：
--
作者：
Donaldson, Paul J;Grey, Angus C;Vaghefi, Ehsan
眼用透镜的光学性质对于整体视觉质量是重要的。作为透明的生物组织，透镜有助于眼睛的整体和动态聚焦能力，并校正由角膜引入的光学误差。透镜的光学特性在整个使用寿命中会发生变化。透镜的折射特性和透明度的改变分别导致老花眼和白内障。然而，还不清楚透镜细胞结构和功能的变化如何引发这些折射和透明度的变化。在这里，我们试图通过回顾如何建立的透镜的光学特性，然后保持在细胞水平的整个生命周期的个人，以弥补这一知识差距。这种理解的核心是透镜具有微循环系统的事实，该微循环系统产生通过透镜循环的离子和水的通量。通过支持透镜中的离子和代谢稳态，该系统主动地保持透镜的透明度，并且通过调节透镜的稳态水含量，控制两个关键参数，即透镜几何形状和折射率梯度，这决定了透镜的折射特性。因此，水的运输正在成为关键参数，在细胞水平上联系的透明度和折射性能的透镜，并强调需要研究如何与年龄有关的变化，水运输导致老花眼和白内障，屈光不正和失明的主要原因在当今世界。
The optical properties of the ocular lens are important to overall vision quality. As a transparent biological tissue, the lens contributes to the overall and dynamic focussing power of the eye, and corrects for optical errors introduced by the cornea. The optical properties of the lens change throughout life. Alterations to the refractive properties and transparency of the lens result in presbyopia and cataract, respectively. However, it is not well understood how changes to lens cellular structure and function initiate these changes in refraction and transparency. Here, we attempt to bridge this knowledge gap by reviewing how the optical properties of the lens are first established, and then maintained at the cellular level throughout the lifetime of an individual. Central to this understanding is the fact that the lens has a microcirculation system that generates a flux of ions and water that circulates through the lens. By supporting ionic and metabolic homeostasis in the lens, the system actively maintains lens transparency, and by regulating the steady state water content of the lens, controls the two key parameters, lens geometry and the gradient of refractive index, which determine the refractive properties of the lens. Thus, water transport is emerging as the critical parameter that links the transparency and refractive properties of the lens at the cellular level, and highlights the need to study how age-related changes in water transport result in presbyopia and cataract, the leading causes of refractive error and blindness in the world today.