Thickened Retinal Nerve Fiber Layers Associated With High-Altitude Headache

Xianhong Yin; Yi Li; Yanyun Ma; Yuan Xie; Kun Wang; Dayan Sun; Xiaoyu Liu; Meng Hao; Meng Liang; Shixuan Zhang; Yuan Guo; Li Jin; Ningli Wang; Jiucun Wang

doi:10.3389/fphys.2022.864222

Thickened Retinal Nerve Fiber Layers Associated With High-Altitude Headache

Front Physiol. 2022 May 4:13:864222. doi: 10.3389/fphys.2022.864222. eCollection 2022.

Authors

Xianhong Yin¹, Yi Li^{1

2

3}, Yanyun Ma^{1

2}, Yuan Xie⁴, Kun Wang¹, Dayan Sun¹, Xiaoyu Liu¹, Meng Hao¹, Meng Liang¹, Shixuan Zhang¹, Yuan Guo¹, Li Jin^{1

3

5

6}, Ningli Wang⁴, Jiucun Wang^{1

6}

Affiliations

¹ Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, and Human Phenome Institute, Fudan University, Shanghai, China.
² Institute for Six-Sector Economy, Fudan University, Shanghai, China.
³ International Human Phenome Institutes, Shanghai, China.
⁴ Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
⁵ Research Institute of Data Sciences, Fudan University, Shanghai, China.
⁶ Research Unit of Dissecting the Population Genetics and Developing New Technologies for Treatment and Prevention of Skin Phenotypes and Dermatological Diseases, Chinese Academy of Medical Sciences (2019RU058), Shanghai, China.

Abstract

Purpose: This study aimed to quantify the different quadrants of the optic nerve head (ONH) and macular parameters and their changes during exposure to high altitude, and to assess their correlation with high-altitude headache (HAH). Methods: Spectral-domain optical coherence tomography (OCT) was used to quantify changes in the retinal structure in 109 healthy subjects during acute exposure to high altitude (3,700 m). Self-reported symptoms of HAH and acute mountain sickness AMS were assessed using Lake Louise Score (LLS), alongside measurements of physiological parameters (oxygen saturation [SpO₂], heart rate [HR], hemoglobin level [Hb], and red blood cell [RBC] count). Measurements were taken before and after exposure to the high-altitude environment. The correlations of these parameters and changes at ONH were examined. Results: With the exposure to high altitude, the incidence of AMS was 44.0% and the frequency of HAH was 67.0% (54.1% mild, 12.9% moderate-severe). As for systemic parameters measured at high altitude, the participants exhibited significantly lower SpO₂, higher resting HR, higher Hb, and a higher RBC (all p < 0.05). Key stereometric parameters used to describe ONH [superior, inferior, nasal, temporal, and mean retinal nerve fiber layer (RNFL) thickness] and macula (macular thickness) increased at high altitude compared with baseline. Most parameters of ONH changed, especially superior, inferior, and mean RNFL thickness (p < 0.05). There was a significant correlation between the ratios of RNFL at ONH and HAH [mean thickness (r = 0.246, p = 0.01); inferior (r = 0.216, p = 0.02); nasal (r = 0.193, p = 0.04)]. No associations between parameters of ONH and AMS or LLS were observed. Conclusion: The high-altitude environment can increase RNFL thickness at ONH. Furthermore, we found that the ratios of mean thickness, inferior area, and nasal area correlated positively with HAH, which provides new insights for understanding of the underlying pathological mechanisms of high-altitude retinopathy (HAR).

Keywords: HAH; OCT; RNFL; headache; high-altitude headache; retinal nerve fiber layer.