In vitro dimensions and curvatures of human lenses
In vitro dimensions and curvatures of human lenses
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DOI：
10.1016/j.visres.2005.10.019
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发表时间：
2006-03-01
期刊：
影响因子：
1.8
通讯作者：
Augusteyn, RC
中科院分区：
文献类型：
--
作者：
Rosen, AM;Denharn, DB;Augusteyn, RC
本研究的目的是使用阴影摄影测量技术来确定切除的人类晶状体的尺寸和曲率。使用改良的光学比较仪和数码相机拍摄放大的矢状面和冠状面透镜轮廓。从这些图像中获得赤道直径、前后矢状厚度、前后曲率和形状因子。数据用于计算透镜体积，并与透镜重量进行比较。对年龄从20岁到99岁的37个人类晶状体进行了测量。这些结果表明，透镜尺寸和前曲率半径在整个成年期呈线性增加，而后曲率保持不变。后透镜的相对形状（或纵横比）在整个成人生活中没有变化，因为赤道直径和后厚度以相同的速率增加。前部厚度与后部厚度的比率恒定为0.70。这表明，在体内的力量改变了明显的位置的透镜赤道，在体外的透镜的形状对应于最大的调节形状在体内和调节和未调节的透镜的形状逐渐向对方收敛，由于透镜的增长与年龄的收敛点位于附近的完全丧失的调节（55-60岁）。总之，这些观察结果为亥姆霍兹调节理论提供了额外的支持。(c)2005爱思唯尔有限公司保留所有权利。
The purpose of this study was to determine dimensions and curvatures of excised human lenses using the technique of shadowphotogrammetry. A modified optical comparator and digital camera were used to photograph magnified sagittal and coronal lens profiles. Equatorial diameter, anterior and posterior sagittal thickness, anterior and posterior curvatures, and shape factors were obtained from these images. The data were used to calculate lens volumes, which were compared with the lens weights. Measurements were made on 37 human lenses ranging in age from 20 to 99 years. These showed that lens dimensions and the anterior radius of curvature increase linearly throughout adult life while posterior curvature remains constant. The relative shape (or aspect ratio) of the posterior lens is unchanged through adult life since both equatorial diameter and posterior thickness increase at the same rate. The ratio of anterior thickness to posterior thickness is constant at 0.70. It is suggested that in vivo forces alter the apparent location of the lens equator, that the in vitro lens shape corresponds to the maximally accommodated shape in vivo and that the shapes of the accommodated and unaccommodated lens progressively converge toward each other due to lens growth with age, with a convergence point located near the age of total loss of accommodation (55-60 years). Together, these observations provide additional support for the Helmholtz theory of accommodation. (c) 2005 Elsevier Ltd. All rights reserved.