Sheybani Arsham, Reitsamer Herbert, Ahmed Iqbal Ike K
Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States.
Department of Ophthalmology, University Clinic Salzburg/SALK, Austria 3Paracelsus Medical University, Salzburg, Austria.
Invest Ophthalmol Vis Sci. 2015 Jul;56(8):4789-95. doi: 10.1167/iovs.15-16625.
The purpose of this study was to describe the fluidics of a novel non-valved glaucoma implant designed to prevent hypotony and compare the fluidics of this device with two commonly used non-valved glaucoma devices.
The XEN 45 micro-fistula implant was designed to limit hypotony by virtue of its length and width according to the Hagen-Poiseuille equation. Flow testing was performed using a syringe pump and pressure transducer at multiple flow rates. The pressure differentials across the XEN implant, the Ex-Press implant, and 10 mm of silicone tubing from a Baerveldt implant at a physiologic flow rate (2.5 μL/min) were extrapolated.
The XEN 45 achieved a steady-state pressure calculated at 7.56 mm Hg at 2.5 μL/min. At the same flow rate, the Ex-Press device and Baerveldt tubing reached steady-state pressures of 0.09 and 0.01 mm Hg, respectively.
Under flow testing, the XEN micro-fistula implant was able to maintain backpressure above numerical hypotony levels without the use of complex valve systems. This is due to the XEN implant's design, derived from the principles that dictate Newtonian fluids.
本研究旨在描述一种旨在预防低眼压的新型无阀青光眼植入物的流体力学特性，并将该装置的流体力学特性与两种常用的无阀青光眼装置进行比较。
根据哈根-泊肃叶方程，XEN 45微瘘植入物的设计旨在通过其长度和宽度来限制低眼压。使用注射泵和压力传感器在多种流速下进行流量测试。推算出在生理流速（2.5 μL/分钟）下，XEN植入物、Ex-Press植入物以及来自Baerveldt植入物的10毫米硅胶管两端的压力差。
XEN 45在2.5 μL/分钟时达到的稳态压力经计算为7.56毫米汞柱。在相同流速下，Ex-Press装置和Baerveldt硅胶管的稳态压力分别为0.09和0.01毫米汞柱。
在流量测试中，XEN微瘘植入物无需使用复杂的阀门系统就能将背压维持在数值上的低眼压水平之上。这归因于XEN植入物的设计，该设计源自支配牛顿流体的原理。
