The Impact of Choroidal Swelling on Optic Nerve Head Deformation
The Impact of Choroidal Swelling on Optic Nerve Head Deformation
复制标题
DOI：
10.1167/iovs.18-24463
复制
发表时间：
2018-08-01
影响因子：
4.4
通讯作者：
Samuels, Brian C.
中科院分区：
文献类型：
--
作者：
Feola, Andrew J.;Nelson, Emily S.;Samuels, Brian C.
目的.脉络膜的几何形状和肿胀被认为是导致眼部病变的原因。因此，重要的是要了解脉络膜如何影响视神经乳头（ONH）的生物力学环境。我们开发了一个有限元模型来研究急性脉络膜肿胀和脉络膜几何形状如何影响ONH变形。我们开发了两种ONH的几何模型：一种是“钝”脉络膜插入，另一种是“锥形”脉络膜插入。我们研究了脉络膜体积变化（2.1-14.2 μ L，估计发生在眼脉冲）如何影响三个组织区域的生物力学应变：前板神经组织，筛板，和后板神经组织。然后，我们进行了敏感性分析，以了解ONH压力，组织材料特性和脉络膜肿胀的变化如何影响峰值组织应变。钝性脉络膜几何结构中的脉络膜肿胀对层前神经组织中的应变有很大影响，其幅度与由于30 mm Hg的IOP而预期发生的幅度相当。锥形脉络膜几何结构中的脉络膜肿胀也影响应变，但与钝性几何结构相比影响程度较小。敏感性分析证实，在钝性脉络膜几何结构中，脉络膜肿胀对层前神经组织应变的影响更大。脉络膜解剖结构和肿胀可以相互作用，在层前神经组织变形中发挥重要作用。这些发现表明脉络膜可能在ONH生物力学中发挥重要且以前未被认识到的作用，并激发更多的研究以更好地定义脉络膜体积变化的体内效应。
PURPOSE. Choroid geometry and swelling have been proposed to contribute to ocular pathologies. Thus, it is important to understand how the choroid may impact the optic nerve head (ONH) biomechanical environment. We developed a finite element model to study how acute choroidal swelling and choroid geometry affect ONH deformation.METHODS. We developed two geometric models of the ONH: one with a "blunt" choroidal insertion and another with a "tapered" choroid insertion. We examined how choroidal volume changes (2.1-14.2 mu L, estimated to occur during the ocular pulse) impact biomechanical strain in three tissue regions: the prelaminar neural tissue, lamina cribrosa, and retrolaminar neural tissue. Then, we performed a sensitivity analysis to understand how variation in ONH pressures, tissue material properties, and choroidal swelling influenced the peak tissue strains.RESULTS. Choroidal swelling in the blunt choroid geometry had a large impact on the strains in the prelaminar neural tissue, with magnitudes comparable to those expected to occur due to an IOP of 30 mm Hg. Choroidal swelling in the tapered choroid geometry also affected strains but to a lesser extent compared to the blunt geometry. A sensitivity analysis confirmed that choroidal swelling was more influential on prelaminar neural tissue strains in the blunt choroid geometry.CONCLUSIONS. Choroid anatomy and swelling can interact to play an important role in prelaminar neural tissue deformation. These findings suggest that the choroid may play an important, and previously unappreciated, role in ONH biomechanics, and motivate additional research to better define the in vivo effects of choroidal volume change.