Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
University Hospitals Coventry and Warwickshire NHS Trust, Coventry, United Kingdom.
Invest Ophthalmol Vis Sci. 2019 Jan 2;60(1):36-40. doi: 10.1167/iovs.18-24966.
Our aim was to assess retinal venous diameter and segmented retinal layer thickness variation in acute systemic hypoxia with and without acetazolamide and to relate these changes to high altitude headache (HAH), as a proxy for intracerebral pathophysiology.
A total of 20 subjects participated in a 4-day ascent to the Margherita Hut (4,559 m) on Monte Rosa in the Italian Alps. Each participant was randomized to either oral acetazolamide 250 mg twice daily or placebo. A combination of digital imaging and optical coherence tomography was used to measure retinal vessel diameter and retinal layer thickness. Clinically-assessed HAH was recorded.
A total of 18 participants had usable digital and OCT images, with 12 developing HAH. Significant thickening was seen only in the two inner layers of the retina, the retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) at P = 0.012 and P = 0.010, respectively, independent of acetazolamide. There was a significant positive correlation between HAH and both retinal venous diameter (T = 4.953, P = 0.001) and retinal artery diameter (T = 2.865, P = 0.015), with both unaffected by acetazolamide (F = 0.439, P = 0.518).
Retinal venous diameter correlates positively with HAH, adding further evidence for the proposed venous outflow limitation mechanism. The inner layers of the retina swelled disproportionately when compared to the outer layers under conditions of systemic hypoxia. Acetazolamide does not appear to influence altitudinal changes of retinal layers and vasculature.
本研究旨在评估急性系统性缺氧时视网膜静脉直径和分段视网膜层厚度的变化，并将这些变化与高海拔头痛（HAH）相关联，以作为颅内病理生理学的替代指标。
共有 20 名受试者参与了一项为期 4 天的攀登意大利阿尔卑斯山罗萨峰玛格丽塔小屋（4559 米）的活动。每位参与者均随机接受每日两次口服乙酰唑胺 250mg 或安慰剂治疗。采用数字成像和光学相干断层扫描（OCT）相结合的方法测量视网膜血管直径和视网膜层厚度。记录临床评估的 HAH。
共有 18 名参与者的数字和 OCT 图像可用，其中 12 名参与者出现 HAH。仅在内层视网膜（视网膜神经纤维层[RNFL]和节细胞层[GCL]）中观察到显著增厚，分别在 P = 0.012 和 P = 0.010 时具有统计学意义，与乙酰唑胺无关。HAH 与视网膜静脉直径（T = 4.953，P = 0.001）和视网膜动脉直径（T = 2.865，P = 0.015）呈显著正相关，而这两者均不受乙酰唑胺影响（F = 0.439，P = 0.518）。
视网膜静脉直径与 HAH 呈正相关，进一步为提出的静脉流出受限机制提供了证据。与系统性缺氧相比，内层视网膜不成比例地肿胀。乙酰唑胺似乎不会影响海拔高度对视网膜层和血管的变化。
