Abstract：
Glaucoma is a progressive optic neuropathy in the eye, which is a leading cause of irreversible blindness worldwide and currently affects over 70 million individuals. Clinically, intraocular pressure (IOP) reduction is the only proven treatment to halt the progression of glaucoma. Microfluidic devices such as glaucoma drainage devices (GDDs) and minimally invasive glaucoma surgery (MIGS) devices are routinely used by ophthalmologists to manage elevated IOP, by creating an artificial pathway for the over-accumulated aqueous humor (AH) in a glaucomatous eye, when the natural pathways are severely blocked. Herein, a detailed modelling and analysis of both the natural microfluidic pathways of the AH in the eye and artificial microfluidic pathways formed additionally by the various glaucoma implants are conducted to provide an insight into the causes of the IOP abnormality and the improvement schemes of current implant designs. The mechanisms of representative glaucoma implants have been critically reviewed from the perspective of microfluidics, and we have categorized the current implants into four groups according to the targeted drainage sites of the AH, namely Schlemm\'s canal, suprachoroidal space, subconjunctival space, and ocular surface. In addition, we propose to divide the development and evolution of glaucoma implant designs into three technological waves, which include microtube (1st), microvalve (2nd) and microsystem (3rd). With the emerging trends of minimal invasiveness and artificial intelligence in the development of medical implants, we envision that a comprehensive glaucoma treatment microsystem is on the horizon, which is featured with active and wireless control of IOP, real-time continuous monitoring of IOP and aqueous rate, etc. The current review could potentially cast light on the unmatched needs, challenges, and future directions of the microfluidic structural and functional designs of glaucoma implants, which would enable an enhanced safety profile, reduced complications, increased efficacy of lowering IOP and reduced IOP fluctuations, closed-loop and on-demand control of IOP, etc.
摘要：
青光眼是眼睛的进行性视神经病变，这是全球不可逆失明的主要原因，目前影响着7000多万人。临床上,降低眼内压（IOP）是唯一被证明可以阻止青光眼进展的治疗方法。诸如青光眼引流装置(GDD)和微创青光眼手术(MIGS)装置的微流体装置通常由眼科医生使用以管理升高的IOP。通过为青光眼中过度积累的房水（AH）创建人工途径，当自然途径被严重阻断时。在这里，对眼内AH的天然微流体通路和由各种青光眼植入物额外形成的人工微流体通路进行详细建模和分析,以提供对IOP异常的原因和当前植入物设计的改进方案的洞察。代表性青光眼植入物的机制已经从微流体的角度进行了严格的审查，我们根据AH的目标引流部位将目前的植入物分为四组，即施莱姆运河，脉络膜上腔,结膜下间隙，和眼表。此外,我们建议将青光眼植入物设计的发展和演变分为三个技术浪潮，其中包括微管（第一），微型阀（第二）和微系统（第三）。随着医学植入物发展的最小侵入性和人工智能的新兴趋势，我们设想一个全面的青光眼治疗微系统即将出现，它具有主动和无线控制IOP的功能，实时连续监测眼压和房水速率，等。当前的审查可能会揭示无与伦比的需求，挑战,以及青光眼植入物的微流控结构和功能设计的未来方向，这将增强安全性，减少并发症,降低IOP和降低IOP波动的功效增加，IOP的闭环和按需控制，等。
