Reverse Pupillary Block Slows Iris Contour Recovery From Corneoscleral Indentation
Reverse Pupillary Block Slows Iris Contour Recovery From Corneoscleral Indentation
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DOI：
10.1115/1.4001256
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发表时间：
2010-07-01
影响因子：
1.7
通讯作者：
Barocas, Victor H.
中科院分区：
文献类型：
--
作者：
Amini, Rouzbeh;Barocas, Victor H.
巩膜压痕改变了虹膜的轮廓，改变了虹膜与角膜之间的角度。虽然这种效应早已被观察到，但其发生的机制仍然知之甚少。先前的理论研究表明，角膜巩膜压痕可以使眼球变形，从而使虹膜根旋转。在这项工作中，我们研究了虹膜根部旋转驱动的虹膜与房水之间的流体结构相互作用。虹膜根部旋转从我们之前的全球模型中获得，被用作前眼流固相互作用有限元模型的边界条件。研究了旋转角度和压痕速度两个参数对虹膜轮廓和房水动力学的影响。我们发现虹膜根部的后旋引起虹膜后弯。当虹膜根恢复到原来的位置后，由于虹膜尖端固定在晶状体上（反向瞳孔阻滞），房水被困在前房。经过0.5-2分钟的模拟，房水进入后房并从前房流出，使系统恢复到原来的稳态流动状态。虹膜根旋转得越快或越远，恢复到稳定状态所需的时间就越长。角膜巩膜压痕后瞳孔反向阻滞可能解释了防止眨眼导致虹膜前移的临床观察。(DOI: 10.1115/1.4001256)
Comeoscleral indentation changes the iris contour and alters the angle between the iris and cornea. Although this effect has long been observed, the mechanism by which it occurs remains poorly understood. Previous theoretical research has shown that corneoscleral indentation can deform the eye globe and codsequently rotate the iris root. In this work, we studied the fluid-structure interaction between the iris and aqueous humor, driven by iris root rotation. The iris root rotation obtained from our previous whole-globe model was used as a boundary condition for a fluid-structure interaction finite element model of the anterior eye. We studied the effect of two parameters-rotation angle and indentation speed-on the iris contour and aqueous humor dynamics. We found that posterior rotation of the iris root caused posterior bowing of the iris. After the iris root was returned to its original orientation, the aqueous humor was trapped in the anterior chamber because the iris tip pinned against the lens (reverse pupillary block). After 0.5-2 min of simulation, aqueous humor secretion into the posterior chamber and outflow from the anterior chamber allowed the system to return to its original steady state flow condition. The faster or farther the iris root rotated, the longer it took to return to steady state. Reverse pupillary block following corneoscleral indentation is a possible explanation for the clinical observation that prevention of blinking causes the iris to drift forward. [DOI: 10.1115/1.4001256]