Department of Thermal & Fluid Engineering, Faculty of Engineering Technology, University of Twente, Enschede, 7522 NB, The Netherlands.
Mechanical, Industrial & Aeronautical Engineering, Faculty of Engineering & the Built Environment, University of Witwatersrand, Johannesburg, Private Bag 3, Johannesburg, Wits, 2050, South Africa.
Sci Rep. 2024 Feb 15;14(1):3777. doi: 10.1038/s41598-023-50491-9.
Glaucoma drainage devices (GDDs) are prosthetic-treatment devices for treating primary open-angle glaucoma. Despite their effectiveness in reducing intraocular pressures (IOP), endothelial cell damage (ECD) is a commonly known side-effect. There have been different hypotheses regarding the reasons for ECD with one being an induced increase in shear on the corneal wall. A computational fluid dynamics (CFD) model was used to investigate this hypothesis in silico. The Ahmed Glaucoma Valve (AGV) was selected as the subject of this study using an idealised 3D model of the anterior chamber with insertion angles and positions that are commonly used in clinical practice. It was found that a tube-cornea distance of 1.27 mm or greater does not result in a wall shear stress (WSS) above the limit where ECD could occur. Similarly, a tube-cornea angle of 45° or more was shown to be preferable. It was also found that the ECD region has an irregular shape, and the aqueous humour flow fluctuates at certain insertion angles and positions. This study shows that pathological amounts of WSS may occur as a result of certain GDD placements. Hence, it is imperative to consider the associated fluid force interactions when performing the GDD insertion procedure.
青光眼引流装置（GDD）是用于治疗原发性开角型青光眼的假体治疗装置。尽管它们在降低眼内压（IOP）方面非常有效，但内皮细胞损伤（ECD）是一种常见的副作用。关于 ECD 的原因有不同的假设，其中一种是角膜壁上剪切力的诱导增加。使用前房的理想化 3D 模型和在临床实践中常用的插入角度和位置，使用计算流体动力学（CFD）模型对这一假设进行了计算机模拟研究。选择 Ahmed Glaucoma Valve（AGV）作为本研究的对象。结果发现，管-角膜距离为 1.27mm 或更大时，不会导致壁剪切应力（WSS）超过可能发生 ECD 的限值。同样，显示出管-角膜角度为 45°或更大是优选的。还发现 ECD 区域的形状不规则，并且在某些插入角度和位置处房水流动波动。这项研究表明，由于某些 GDD 的放置，可能会发生病理性的 WSS。因此，在进行 GDD 插入手术时，必须考虑相关的流体力相互作用。
