CILIARY MUSCLE AGING AND PRESBYOPIA

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 目的：通过研究非人灵长类动物的调节和老视的动态变化来了解人类的老花眼。 非人灵长类动物是人类老花眼的首选模型，即与年龄相关的注意力能力丧失。猴子晶状体的赤道直径不随年龄变化；因此，像人类一样，老花眼不能归因于与年龄相关的晶状体直径的增加。 此外，我们还确定了在中脑刺激过程中参与调节的眼内结构的实时动力学。这些研究产生了关于调节机制的新信息。随着年龄的增长，睫状肌与后小带(弹性纤维从小带神经丛向前方延伸至靠近肌肉后端的玻璃体膜)之间的距离增加。老年眼睫状肌后带及其后部附着点可调节睫状肌收缩和调节幅度，抑制睫状肌调节反应。 此外，该胶囊有助于睫状体向前调节运动。晶状体物质提取程序使晶状体囊保持完整，类似于人类临床使用的程序，不会影响调节系统的运动，这是发展调节性人工晶状体(IOL)的一个重要发现。年龄相关的几何构型和后透明带功能的改变是否会让较老的调节装置仍然形成可调节的人工晶状体，将取决于人工晶状体的特性和囊膜能施加多大的力。如果老花眼依靠向心肌和囊膜的运动而不是靠向前的肌肉运动，除非能切断较老的后囊，否则调节性人工晶状体在恢复老花眼的调节方面可能会更有效。这项研究使用了WNPRC Research Services。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Objective: To understand human presbyopia by studying the dynamics of accommodation and presbyopia in nonhuman primates. Nonhuman primates are the preferred model for human presbyopia, the age-related loss of the ability to focus. The equatorial diameter of the monkey lens does not change with age; thus, as in humans, presbyopia can not be attributed to an age-related increase in lens diameter. Further, we determined the real-time dynamics of the intraocular structures involved in accommodation during midbrain stimulation. These studies generated new information about the mechanisms of accommodation. There is an age-related change in the geometry of the accommodative apparatus; with increased age the distance between the ciliary muscle and the posterior zonule (the elastic fibers extend from the zonular plexus anteriorly to the vitreous membrane near the posterior end of the muscle) increases. The posterior zonule and its posterior insertion point may moderate ciliary muscle contraction and accommodative amplitude and may dampen the ciliary muscle accommodative response in the older eye. Also, the capsule facilitates forward accommodative ciliary body movement. Lens substance extraction procedures that leave the capsule intact, similar to those used clinically in humans, do not affect the accommodative system movements, an important finding for the development of accommodating intraocular lenses (IOLs). Whether the age-related changes in geometry and posterior zonule function will allow the older accommodative apparatus to still mold an accommodating IOL would depend on the characteristics of the IOL and how much force the capsule can exert. Unless the older posterior zonule can be severed, accommodating IOLs may be more effective in restoring accommodation in the presbyopic eye if they rely on centripetal muscle and capsular movements rather than on forward muscle movement. This research used WNPRC Research Services.