Croft M A, Kaufman P L, Crawford K S, Neider M W, Glasser A, Bito L Z
Department of Ophthalmology and Visual Sciences, Wisconsin Regional Primate Research Center, University of Wisconsin, Madison, Wisconsin 53792, USA.
Am J Physiol. 1998 Dec;275(6):R1885-97. doi: 10.1152/ajpregu.1998.275.6.R1885.
Accommodation, the mechanism by which the eye focuses on near objects, is lost with increasing age in humans and monkeys. This pathophysiology, called presbyopia, is poorly understood. We studied aging-related changes in the dynamics of accommodation in rhesus monkeys aged 4-24 yr after total iridectomy and midbrain implantation of an electrode to permit visualization and stimulation, respectively, of the eye's accommodative apparatus. Real-time video techniques were used to capture and quantify images of the ciliary body and lens. During accommodation in youth, ciliary body movement was biphasic, lens movement was monophasic, and both slowed as the structures approached their new steady-state positions. Disaccommodation occurred more rapidly for both ciliary body and lens, but with longer latent period, and slowed near the end point. With increasing age, the amplitude of lens and ciliary body movement during accommodation declined, as did their velocities. The latent period of lens and ciliary body movements increased, and ciliary body movement became monophasic. The latent period of lens and ciliary body movement during disaccommodation was not significantly correlated with age, but their velocity declined significantly. The age-dependent decline in amplitude and velocity of ciliary body movements during accommodation suggests that ciliary body dysfunction plays a role in presbyopia. The age changes in lens movement could be a consequence of increasing inelasticity or hardening of the lens, or of age changes in ciliary body motility.
调节是眼睛聚焦于近物的机制，在人类和猴子中，随着年龄增长会逐渐丧失。这种病理生理学现象称为老花眼，目前人们对此了解甚少。我们研究了4至24岁恒河猴在接受全虹膜切除并在中脑植入电极后调节动力学的衰老相关变化，该电极分别用于可视化和刺激眼睛的调节装置。使用实时视频技术来捕捉和量化睫状体和晶状体的图像。在年轻时的调节过程中，睫状体运动是双相的，晶状体运动是单相的，并且随着结构接近其新的稳态位置，两者都会减慢。睫状体和晶状体的放松过程发生得更快，但潜伏期更长，并且在终点附近会减慢。随着年龄的增长，调节过程中晶状体和睫状体运动的幅度下降，速度也下降。晶状体和睫状体运动的潜伏期增加，并且睫状体运动变为单相。放松过程中晶状体和睫状体运动的潜伏期与年龄没有显著相关性，但其速度显著下降。调节过程中睫状体运动幅度和速度随年龄的下降表明睫状体功能障碍在老花眼中起作用。晶状体运动的年龄变化可能是晶状体弹性增加或硬化的结果，也可能是睫状体运动性的年龄变化的结果。
