Mehr Jafar A, Moss Heather E, Hatami-Marbini Hamed
Computational Biomechanics Research Laboratory, Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, IL 60612, USA.
Departments of Ophthalmology and Neurology & Neurosciences, Stanford University, Palo Alto, CA 94303, USA.
Life (Basel). 2020 Nov 28;10(12):316. doi: 10.3390/life10120316.
Flattening of the posterior eye globe in the magnetic resonance (MR) images is a sign associated with elevated intracranial pressure (ICP), often seen in people with idiopathic intracranial hypertension (IIH). The exact underlying mechanisms of globe flattening (GF) are not fully known but mechanical factors are believed to play a role. In the present study, we investigated the effects of material properties and pressure loads on GF. For this purpose, we used a generic finite element model to investigate the deformation of the posterior eyeball. The degree of GF in numerical models and the significance of different mechanical factors on GF were characterized using an automated angle-slope technique and a statistical measure. From the numerical models, we found that ICP had the most important role in GF. We also showed that the angle-slope graphs pertaining to MR images from five people with high ICP can be represented numerically by manipulating the parameters of the finite element model. This numerical study suggests that GF observed in IIH patients can be accounted for by the forces caused by elevation of ICP from its normal level, while material properties of ocular tissues, such as sclera (SC), peripapillary sclera (PSC), and optic nerve (ON), would impact its severity.
磁共振（MR）图像中眼球后部变平是与颅内压（ICP）升高相关的体征，常见于特发性颅内高压（IIH）患者。眼球变平（GF）的确切潜在机制尚不完全清楚，但据信机械因素起了作用。在本研究中，我们调查了材料特性和压力负荷对GF的影响。为此，我们使用了一个通用的有限元模型来研究眼球后部的变形。使用自动角度-斜率技术和统计量来表征数值模型中的GF程度以及不同机械因素对GF的意义。从数值模型中，我们发现ICP在GF中起最重要的作用。我们还表明，通过操纵有限元模型的参数，可以用数值表示来自五名高ICP患者的MR图像的角度-斜率图。这项数值研究表明，IIH患者中观察到的GF可以由ICP从正常水平升高所产生的力来解释，而眼组织的材料特性，如巩膜（SC）、视乳头周围巩膜（PSC）和视神经（ON），会影响其严重程度。
