Unconventional aqueous humor outflow: A review.
Unconventional aqueous humor outflow: A review.
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DOI：
10.1016/j.exer.2016.01.017
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发表时间：
2017-05
影响因子：
3.4
通讯作者：
Overby DR
中科院分区：
文献类型：
--
作者：
Johnson M;McLaren JW;Overby DR
房水主要通过包括小梁网和施莱姆管的传统流出路径流出眼睛。然而，一小部分房水通过替代或“非常规”途径，包括睫状肌、睫状体上腔和脉络膜上腔。从那里，非常规的流出可能通过两条途径排出：葡萄膜巩膜途径，其中房水穿过巩膜被眼眶血管再吸收；以及葡萄膜涡流途径，其中房水进入脉络膜并通过涡静脉排出。我们回顾了这些途径的解剖学、生理学和药理学。我们还讨论了确定非常规流出率的方法，包括使用从非常规途径中的组织中回收的放射性或荧光示踪剂的直接技术，以及根据一定压力范围内的总流出量估计非常规流出量的间接方法。间接方法受到许多假设的影响，通常与示踪剂测量的一致性较差。我们回顾了用于研究常规和非常规流出的各种动物模型。小鼠似乎是一个有前途的模型，因为它捕获了人类常见的常规和非常规流出动力学的几个方面，尽管关于小鼠非常规流出的幅度仍然存在疑问。最后，我们回顾未来的方向。显然需要开发改进的方法来测量动物和人类的非常规流出量。
Aqueous humor flows out of the eye primarily through the conventional outflow pathway that includes the trabecular meshwork and Schlemm's canal. However, a fraction of aqueous humor passes through an alternative or ‘unconventional’ route that includes the ciliary muscle, supraciliary and suprachoroidal spaces. From there, unconventional outflow may drain through two pathways: a uveoscleral pathway where aqueous drains across the sclera to be resorbed by orbital vessels, and a uveovortex pathway where aqueous humor enters the choroid to drain through the vortex veins. We review the anatomy, physiology and pharmacology of these pathways. We also discuss methods to determine unconventional outflow rate, including direct techniques that use radioactive or fluorescent tracers recovered from tissues in the unconventional pathway and indirect methods that estimate unconventional outflow based on total outflow over a range of pressures. Indirect methods are subject to a number of assumptions and generally give poor agreement with tracer measurements. We review the variety of animal models that have been used to study conventional and unconventional outflow. The mouse appears to be a promising model because it captures several aspects of conventional and unconventional outflow dynamics common to humans, although questions remain regarding the magnitude of unconventional outflow in mice. Finally, we review future directions. There is a clear need to develop improved methods for measuring unconventional outflow in both animals and humans.