Tweedy Jennifer H, Pralits Jan O, Repetto Rodolfo, Soleri Paolo
Department of Bioengineering, Imperial College London, London, UK.
D.I.C.C.A. Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa, Italy.
Math Med Biol. 2018 Sep 11;35(3):363-385. doi: 10.1093/imammb/dqx007.
Flow in the aqueous humour that fills the anterior chamber of the eye occurs in response to the production and drainage of the aqueous humour, and also due to buoyancy effects produced by thermal gradients. Phakic intraocular lenses are manufactured lenses that are surgically inserted in the eyes of patients to correct refractive errors. Their presence has a dramatic effect on the circulation of the aqueous humour, resulting a very different flow in the anterior chamber, the effects of which have not been extensively investigated. In this article we use a simplified mathematical model to analyse the flow, in order to assess the effect of the implanted lens on the pressure drop required to drive the flow and also on the wall shear stress experienced by the corneal endothelial cells and the cells of the iris. A high pressure drop could result in an increased risk of glaucoma, whilst raised shear stress on the cornea could result in a reduction in the density of endothelial cells there, and on the iris it could result in the detachment of pigment cells, which block the outflow of the eye, also leading to glaucoma. Our results confirm those of previous fully numerical studies, and show that, although the presence of the lens causes significant differences in the flow topology and direction, the typical magnitudes of the shear stress are not significantly changed from the natural case. Our semi-analytical solution allows us to perform a thorough study of the dependence of the results on the controlling parameters and also to understand the basic physical mechanisms underlying flow characteristics.
填充眼球前房的房水流动是由房水的产生和排出引起的，同时也归因于热梯度产生的浮力效应。有晶状体眼人工晶状体是通过手术植入患者眼睛以矫正屈光不正的人造透镜。它们的存在对房水的循环有显著影响，导致前房内的流动非常不同，其影响尚未得到广泛研究。在本文中，我们使用一个简化的数学模型来分析这种流动，以便评估植入的晶状体对驱动流动所需的压降以及角膜内皮细胞和虹膜细胞所经历的壁面剪应力的影响。高压降可能会增加患青光眼的风险，而角膜上剪应力的增加可能会导致那里的内皮细胞密度降低，在虹膜上则可能导致色素细胞脱离，从而阻碍眼睛的房水流出，也会导致青光眼。我们的结果证实了先前完全数值研究的结果，并表明，尽管晶状体的存在会导致流动拓扑结构和方向出现显著差异，但剪应力的典型大小与自然情况相比并没有显著变化。我们的半解析解使我们能够对结果对控制参数的依赖性进行全面研究，并理解流动特性背后的基本物理机制。
