Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Australia.
College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Western Australia, Australia.
PLoS One. 2019 Apr 9;14(4):e0214961. doi: 10.1371/journal.pone.0214961. eCollection 2019.
In this paper we set the previously reported pressure-dependent, ordinary differential equation outflow model by Smith and Gardiner for the human eye, into a new three-dimensional (3D) porous media outflow model of the eye, and calibrate model parameters using data reported in the literature. Assuming normal outflow through anterior pathways, we test the ability of 3D flow model to predict the pressure elevation with a silicone oil tamponade. Then assuming outflow across the retinal pigment epithelium is normal, we test the ability of the 3D model to predict the pressure elevation in Schwartz-Matsuo syndrome. For the first time we find the flow model can successfully model both conditions, which helps to build confidence in the validity and accuracy of the 3D pressure-dependent outflow model proposed here. We employ this flow model to estimate the translaminar pressure gradient within the optic nerve head of a normal eye in both the upright and supine postures, and during the day and at night. Based on a ratio of estimated and measured pressure gradients, we define a factor of safety against acute interruption of axonal transport at the laminar cribrosa. Using a completely independent method, based on the behaviour of dynein molecular motors, we compute the factor of safety against stalling the dynein molecule motors, and so compromising retrograde axonal transport. We show these two independent methods for estimating factors of safety agree reasonably well and appear to be consistent. Taken together, the new 3D pressure-dependent outflow model proves itself to capable of providing a useful modeling platform for analyzing eye behaviour in a variety of physiological and clinically useful contexts, including IOP elevation in Schwartz-Matsuo syndrome and with silicone oil tamponade, and potentially for risk assessment for optic glaucomatous neuropathy.
在本文中，我们将 Smith 和 Gardiner 先前报道的依赖压力的常微分方程流出模型应用于人类眼睛的新的三维（3D）多孔介质流出模型，并使用文献中报道的数据来校准模型参数。假设正常通过前路径流出，我们测试 3D 流动模型预测硅油填塞时眼压升高的能力。然后，假设视网膜色素上皮的流出正常，我们测试 3D 模型预测 Schwartz-Matsuo 综合征时眼压升高的能力。我们首次发现该流动模型能够成功模拟这两种情况，这有助于建立对本文提出的 3D 压力依赖流出模型的有效性和准确性的信心。我们使用该流动模型来估计正常眼在直立和仰卧姿势、白天和晚上视盘内的跨层压梯度。基于估计的和测量的压力梯度之比，我们定义了在 laminar cribrosa 处防止轴突运输急性中断的安全系数。基于 dynein 分子马达的行为，我们使用完全独立的方法来计算防止 dynein 分子马达失速并因此危及逆行轴突运输的安全系数。我们表明，这两种独立的方法估计安全系数的结果相当吻合，并且似乎是一致的。总之，新的 3D 压力依赖流出模型证明了自己能够为分析各种生理和临床有用的情况下眼睛的行为提供有用的建模平台，包括 Schwartz-Matsuo 综合征和硅油填塞时的眼压升高，以及潜在的视神经青光眼性神经病风险评估。
