Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States.
University of Maryland School of Medicine, Baltimore, Maryland, United States.
Invest Ophthalmol Vis Sci. 2024 Sep 3;65(11):33. doi: 10.1167/iovs.65.11.33.
The purpose of this study was to identify and measure plexus-specific absolute retinal capillary blood flow velocity and acceleration in vivo in both nonhuman primates (NHPs) and humans using erythrocyte mediated angiography (EMA) and optical coherence tomography angiography (OCTA).
EMA and OCTA scans centered on the fovea were obtained in 2 NHPs and 11 human subjects. Scans were also obtained in NHP eyes while IOP was experimentally elevated. Erythrocyte velocity and acceleration in retinal arteries, capillaries, and veins were measured and capillaries were categorized based on location within the superficial vascular (SVP), intermediate capillary (ICP), or deep capillary plexus (DCP). Generalized linear mixed models were used to estimate the effects of intraocular pressure (IOP) on capillary blood flow.
Capillary erythrocyte velocity at baseline IOP was 0.64 ± 0.29 mm/s in NHPs (range of 0.14 to 1.85 mm/s) and 1.55 ± 0.65 mm/s in humans (range of 0.46 to 4.50 mm/s). Mean erythrocyte velocity in the SVP, ICP, and DCP in NHPs was 0.69 ± 0.29 mm/s, 0.53 ± 0.22 mm/s, and 0.63 ± 0.27 mm/s, respectively (P = 0.14 for NHP-1 and P = 0.28 for NHP-2). Mean erythrocyte velocity in the human subjects did not differ significantly among SVP, ICP, and DCP (1.46 ± 0.59 mm/s, 1.58 ± 0.55 mm/s, and 1.59 ± 0.79 mm/s, P = 0.36). In NHPs, every 1 mm Hg increase in IOP was associated with a 0.13 mm/s reduction in arterial velocity, 0.10 mm/s reduction in venous velocity, and 0.01 mm/s reduction in capillary velocity (P < 0.001) when accounting for differences in mean arterial pressure (MAP).
Blood flow by direct visualization of individual erythrocytes can be quantified within capillary plexuses. Capillary velocity decreased with experimental IOP elevation.
本研究旨在使用红细胞介导的血管造影（EMA）和光相干断层扫描血管造影（OCTA），在非人类灵长类动物（NHPs）和人类中识别和测量特定于丛状的视网膜毛细血管内绝对血流速度和加速度。
在 2 只 NHPs 和 11 名人类受试者的中央凹处获得 EMA 和 OCTA 扫描。在 NHPs 眼内眼压（IOP）实验性升高时也获得了扫描。测量视网膜动脉、毛细血管和静脉中的红细胞速度和加速度，并根据在浅层血管丛（SVP）、中间毛细血管（ICP）或深层毛细血管丛（DCP）内的位置对毛细血管进行分类。使用广义线性混合模型来估计眼内压（IOP）对毛细血管血流的影响。
在基础 IOP 下，NHPs 的毛细血管红细胞速度为 0.64 ± 0.29mm/s（范围为 0.14 至 1.85mm/s），人类为 1.55 ± 0.65mm/s（范围为 0.46 至 4.50mm/s）。NHPs 中 SVP、ICP 和 DCP 的平均红细胞速度分别为 0.69 ± 0.29mm/s、0.53 ± 0.22mm/s 和 0.63 ± 0.27mm/s（NHP-1 为 P = 0.14，NHP-2 为 P = 0.28）。人类受试者的 SVP、ICP 和 DCP 之间的平均红细胞速度没有显著差异（1.46 ± 0.59mm/s、1.58 ± 0.55mm/s 和 1.59 ± 0.79mm/s，P = 0.36）。在 NHPs 中，当考虑平均动脉压（MAP）的差异时，IOP 每升高 1mmHg，动脉速度降低 0.13mm/s，静脉速度降低 0.10mm/s，毛细血管速度降低 0.01mm/s（P <0.001）。
可以通过直接可视化单个红细胞来量化毛细血管丛内的血流。毛细血管速度随实验性 IOP 升高而降低。
