De Abreu Jérémy, Paillisser Aymeric, Berquet Florence, Hogg Stephen, Trucco Emanuele, Geiser Martial H, Pichon Aurélien, Furian Michael, Stauffer Emeric, Champigneulle Benoit, Brugniaux Julien Vincent, Macgillivray Thomas J, Vergès Samuel, Chiquet Christophe
Department of Ophthalmology, University Hospital of Grenoble Alpes, Grenoble Alpes University, Grenoble, France.
University of Grenoble Alpes, INSERM, HP2 Laboratory, Grenoble, France.
Invest Ophthalmol Vis Sci. 2025 Jun 2;66(6):50. doi: 10.1167/iovs.66.6.50.
The aim of this study was to characterize changes in retinal vessel diameters and choroidal blood flow in healthy lowlanders during a high-altitude expedition.
Ocular examination, fundus images acquired using a handheld camera, and laser Doppler flowmetry (LDF) measurements within the subfoveal choroid (blood flow = ChBF, blood velocity = ChVel, and blood volume = ChVol) were carried out at 200 m and after 9 days at 5100 m in 11 healthy participants. Fundus images were analyzed with the semi-automatic software Vessel Assessment and Measurement Platform for Images of the Retina (VAMPIRE) version 3.2 to quantify retinal vessel parameters: the central retinal artery equivalent (CRAE), the central retinal vein equivalent (CRVE), and arterial and venular tortuosity. Hematocrit and hemoglobin concentrations were also measured at both altitudes.
Corneal thickness increased slightly at altitude (median = 536 µm, interquartile range = 25-75%: [521-571] at 200 m vs. 561 µm [540-574] at 5100 m, P = 0.004). No participant was affected by high-altitude retinopathy. From 200 m to 5100 m, ChVol and ChBF decreased significantly (-31% [43-22], P = 0.003 and -13% [22-8], P = 0.01, respectively), ChVel increased (+17% [10-44], P = 0.003), and CRVE (+10% [3-14], P = 0.04) and venular tortuosity (+142% [71-168], P = 0.04) increased significantly. The altitude-induced increase in hematocrit correlated negatively with the decrease in ChBF (r = -0.88, P < 0.001) and positively with the increase in CRVE (r = 0.88, P = 0.01).
Acute high-altitude exposure leads to a decrease of ChBF (partly related to a decrease in blood volume) and an increase in retinal vein diameter and tortuosity. The physiological consequences of these changes on retinal blood flow and retinal function remain to be explored.
本研究旨在描述健康低地居民在高海拔探险期间视网膜血管直径和脉络膜血流的变化。
对11名健康参与者在海拔200米处以及在海拔5100米处停留9天后进行眼部检查、使用手持相机获取眼底图像，并测量黄斑下脉络膜的激光多普勒血流仪（LDF）参数（血流=ChBF，血流速度=ChVel，血容量=ChVol）。使用半自动软件视网膜图像血管评估与测量平台（VAMPIRE）3.2版分析眼底图像，以量化视网膜血管参数：视网膜中央动脉等效直径（CRAE）、视网膜中央静脉等效直径（CRVE）以及动静脉迂曲度。同时测量两个海拔高度下的血细胞比容和血红蛋白浓度。
海拔高度下角膜厚度略有增加（中位数=536µm，四分位间距=25 - 75%：海拔200米时为[521 - 571]，海拔5100米时为561µm[540 - 574]，P = 0.004）。没有参与者受到高原视网膜病变的影响。从海拔200米到5100米，ChVol和ChBF显著降低（分别为-31%[43 - 22]，P = 0.003和-13%[22 - 8]，P = 0.01），ChVel增加（+17%[10 - 44]，P = 0.003），CRVE（+10%[3 - 14]，P = 0.04）和静脉迂曲度（+142%[71 - 168]，P = 0.04）显著增加。海拔引起的血细胞比容增加与ChBF降低呈负相关（r = -0.88, P < 0.001），与CRVE增加呈正相关（r = 0.88, P = 0.01）。
急性高海拔暴露导致ChBF降低（部分与血容量减少有关）以及视网膜静脉直径和迂曲度增加。这些变化对视网膜血流和视网膜功能的生理影响仍有待探索。
