The retinal tissue is highly metabolically active and is responsible for translating the visual stimuli into electrical signals to be delivered to the brain. A complex vascular structure ensures an adequate supply of blood and oxygen, which is essential for the function and survival of the retinal tissue. To date, a complete understanding of the configuration of the retinal vascular structures is still lacking. Optical coherence tomography angiography has made available a huge amount of imaging data regarding the main retinal capillary plexuses, namely the superficial capillary plexuses (SCP), intermediate capillary plexuses (ICP) and deep capillary plexuses (DCP). However, the interpretation of these data is still controversial. In particular, the question of whether the three capillary plexuses are connected in series or in parallel remains a matter of debate. In this work, we address this question by utilizing a multi-scale/multi-physics mathematical model to quantify the impact of the two hypothesized vascular configurations on retinal hemodynamics and oxygenation. The response to central retinal vein occlusion (CRVO) and intraocular pressure (IOP) elevation is also simulated depending on whether the capillary plexuses are connected in series or in parallel. The simulation results show the following: (i) in the in series configuration, the plexuses exhibit a differential response, with DCP and ICP experiencing larger pressure drops than SCP; and (ii) in the in parallel configuration, the blood flow redistributes uniformly in the three plexuses. The different vascular configurations show different responses also in terms of oxygen profiles: (i) in the in series configuration, the outer nuclear layer, outer plexiform layer and inner nuclear layer (INL) are those most affected by CRVO and IOP elevation; and (ii) in the in parallel configuration the INL and ganglion cell layer are those most affected. The in series results are consistent with studies on paracentral acute middle maculopathy, secondary to CRVO and with studies on IOP elevation, in which DCP and ICP and the retinal tissues surrounding them are those most affected by ischemia. These findings seem to suggest that the in series configuration better describes the physiology of the vascular retinal capillary network in health and disease.

中文翻译：

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基于OCTA数据的视网膜毛细血管丛血管配置理论研究的多尺度/多物理模型。

视网膜组织具有高度的新陈代谢活性，负责将视觉刺激转化为电信号以传递到大脑。复杂的血管结构确保了充足的血液和氧气供应，这对于视网膜组织的功能和生存至关重要。迄今为止，仍然缺乏对视网膜血管结构配置的完整了解。光学相干断层扫描血管造影已经提供了大量关于主要视网膜毛细血管丛的成像数据，即浅层毛细血管丛（SCP）、中间毛细血管丛（ICP）和深部毛细血管丛（DCP）。然而，对这些数据的解释仍然存在争议。尤其，三个毛细血管丛是串联还是并联的问题仍然存在争议。在这项工作中，我们通过利用多尺度/多物理数学模型来量化两种假设的血管配置对视网膜血流动力学和氧合的影响来解决这个问题。对视网膜中央静脉阻塞 (CRVO) 和眼内压 (IOP) 升高的反应也可以根据毛细血管丛是串联还是并联来模拟。模拟结果表明：（i）在串联配置中，丛表现出不同的响应，DCP 和 ICP 的压降比 SCP 大；(ii) 在平行配置中，血流在三个神经丛中重新分布均匀。不同的血管配置在氧气分布方面也表现出不同的反应：（i）在串联配置中，外核层、外丛状层和内核层（INL）受 CRVO 和 IOP 升高的影响最大；(ii) 在并联配置中，INL 和神经节细胞层受影响最大。系列结果与对继发于 CRVO 的旁中央急性中间黄斑病变的研究以及对 IOP 升高的研究一致，其中 DCP 和 ICP 及其周围的视网膜组织受缺血影响最大。这些发现似乎表明串联配置更好地描述了血管视网膜毛细血管网络在健康和疾病中的生理学。外核层、外丛状层和内核层 (INL) 受 CRVO 和 IOP 升高的影响最大；(ii) 在并联配置中，INL 和神经节细胞层受影响最大。系列结果与对继发于 CRVO 的旁中央急性中间黄斑病变的研究以及对 IOP 升高的研究一致，其中 DCP 和 ICP 及其周围的视网膜组织受缺血影响最大。这些发现似乎表明串联配置更好地描述了血管视网膜毛细血管网络在健康和疾病中的生理学。外核层、外丛状层和内核层 (INL) 受 CRVO 和 IOP 升高的影响最大；(ii) 在并联配置中，INL 和神经节细胞层受影响最大。系列结果与对继发于 CRVO 的旁中央急性中间黄斑病变的研究以及对 IOP 升高的研究一致，其中 DCP 和 ICP 及其周围的视网膜组织受缺血影响最大。这些发现似乎表明串联配置更好地描述了血管视网膜毛细血管网络在健康和疾病中的生理学。系列结果与对继发于 CRVO 的旁中央急性中间黄斑病变的研究以及对 IOP 升高的研究一致，其中 DCP 和 ICP 及其周围的视网膜组织受缺血影响最大。这些发现似乎表明串联配置更好地描述了血管视网膜毛细血管网络在健康和疾病中的生理学。系列结果与对继发于 CRVO 的旁中央急性中间黄斑病变的研究以及对 IOP 升高的研究一致，其中 DCP 和 ICP 及其周围的视网膜组织受缺血影响最大。这些发现似乎表明串联配置更好地描述了血管视网膜毛细血管网络在健康和疾病中的生理学。