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Wang TW, Huang MK, Hsu CC, Jo SY, Lin YK, How CK, Tseng SF, Chung K, Chien DK, Chang WH, Chiu YH. High myopia at high altitudes. Front Physiol 2024; 15:1350051. [PMID: 38523807 PMCID: PMC10957768 DOI: 10.3389/fphys.2024.1350051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/08/2024] [Indexed: 03/26/2024] Open
Abstract
Background: Optic nerve sheath diameter (ONSD) increases significantly at high altitudes, and is associated with the presence and severity of acute mountain sickness (AMS). Exposure to hypobaria, hypoxia, and coldness when hiking also impacts intraocular pressure (IOP). To date, little is known about ocular physiological responses in trekkers with myopia at high altitudes. This study aimed to determine changes in the ONSD and IOP between participants with and without high myopia (HM) during hiking and to test whether these changes could predict symptoms of AMS. Methods: Nine participants with HM and 18 without HM participated in a 3-day trek of Xue Mountain. The ONSD, IOP, and questionnaires were examined before and during the trek of Xue Mountain. Results: The ONSD values increased significantly in both HM (p = 0.005) and non-HM trekkers (p = 0.018) at an altitude of 1,700 m. In the HM group, IOP levels were greater than those in the non-HM group (p = 0.034) on the first day of trekking (altitude: 3,150 m). No statistically significant difference was observed between the two groups for the values of ONSD. Fractional changes in ONSD at an altitude of 1,700 m were related to the development of AMS (r pb = 0.448, p = 0.019) and the presence of headache symptoms (r pb = 0.542, p = 0.004). The area under the ROC curve for the diagnostic performance of ONSD fractional changes at an altitude of 1,700 m was 0.859 for predicting the development of AMS and 0.803 for predicting the presence of headache symptoms. Conclusion: Analysis of changes in ONSD at moderate altitude could predict AMS symptoms before an ascent to high altitude. Myopia may impact physiological accommodation at high altitudes, and HM trekkers potentially demonstrate suboptimal regulation of aqueous humor in such environments.
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Affiliation(s)
- Ta-Wei Wang
- Department of Emergency Medicine, Taoyuan General Hospital, Ministry of Health and Welfare, Taoyuan, Taiwan
| | - Ming-Kun Huang
- Department of Emergency Medicine, MacKay Memorial Hospital, Taipei, Taiwan
- Department of Medicine, MacKay Medical College, New Taipei City, Taiwan
- Department of Electronic Engineering, National Taipei University of Technology, Taipei, Taiwan
| | - Chih-Chun Hsu
- Department of Emergency, Hsinchu MacKay Memorial Hospital, Hsinchu, Taiwan
| | - Szu-Yang Jo
- Department of Emergency Medicine, MacKay Memorial Hospital, Taipei, Taiwan
| | - Yen-Kuang Lin
- Graduate Institute of Athletics and Coaching Science, National Taiwan Sport University, Taoyuan, Taiwan
| | - Chorng-Kuang How
- Department of Emergency Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Emergency Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shih-Fen Tseng
- Department of Emergency Medicine, Taoyuan General Hospital, Ministry of Health and Welfare, Taoyuan, Taiwan
| | - Kong Chung
- Department of Emergency Medicine, Taoyuan General Hospital, Ministry of Health and Welfare, Taoyuan, Taiwan
| | - Ding-Kuo Chien
- Department of Emergency Medicine, MacKay Memorial Hospital, Taipei, Taiwan
- Department of Medicine, MacKay Medical College, New Taipei City, Taiwan
| | - Wen-Han Chang
- Department of Emergency Medicine, MacKay Memorial Hospital, Taipei, Taiwan
- Department of Medicine, MacKay Medical College, New Taipei City, Taiwan
| | - Yu-Hui Chiu
- Department of Emergency Medicine, MacKay Memorial Hospital, Taipei, Taiwan
- Department of Medicine, MacKay Medical College, New Taipei City, Taiwan
- Department of Emergency, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
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Liu HM, Chiang IJ, Kuo KN, Liou CM, Chen C. The effect of acetazolamide on sleep apnea at high altitude: a systematic review and meta-analysis. Ther Adv Respir Dis 2016; 11:20-29. [PMID: 28043212 PMCID: PMC5941979 DOI: 10.1177/1753465816677006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Background: Acetazolamide has been investigated for treating sleep apnea in newcomers
ascending to high altitude. This study aimed to assess the effect of
acetazolamide on sleep apnea at high altitude, determine the optimal
therapeutic dose, and compare its effectiveness in healthy trekkers and
obstructive sleep apnea (OSA) patients. Methods: PubMed, Embase, Scopus, Cochrane Library, and Airiti Library databases were
searched up to July 2015 for randomized controlled trials (RCTs) performed
above 2500 m in lowlanders and that used acetazolamide as intervention in
sleep studies. Studies including participants with medical conditions other
than OSA were excluded. Results: Eight studies of 190 adults were included. In healthy participants, the
pooled mean effect sizes of acetazolamide on Apnea–Hypopnea Index (AHI),
percentage of periodic breathing time, and nocturnal oxygenation were 34.66
[95% confidence interval (CI) 25.01–44.30] with low heterogeneity
(p = 0.7, I2 = 0%), 38.56%
(95% CI 18.92–58.19%) with low heterogeneity (p = 0.24,
I2 = 28%), and 4.75% (95% CI 1.35–8.15%)
with high heterogeneity (p < 0.01,
I2 = 87%), respectively. In OSA patients,
the pooled mean effect sizes of acetazolamide on AHI and nocturnal
oxygenation were 13.18 (95% CI 9.25–17.1) with low heterogeneity
(p = 0.33, I2 = 0%) and
1.85% (95% CI 1.08–2.62%) with low heterogeneity (P = 0.56,
I2 = 0%). Conclusions: Acetazolamide improves sleep apnea at high altitude by decreasing AHI and
percentage of periodic breathing time and increasing nocturnal oxygenation.
Acetazolamide is more beneficial in healthy participants than in OSA
patients, and a 250 mg daily dose may be as effective as higher daily doses
for healthy trekkers.
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Affiliation(s)
- Hsin-Ming Liu
- Graduate Institute of Medical Sciences, College
of Medicine, Taipei Medical University, Taipei, Taiwan
| | - I-Jen Chiang
- Graduate Institute of Data Science, Taipei
Medical University, Taipei, Taiwan
| | - Ken N. Kuo
- Cochrane Taiwan, Taipei Medical University and
Department of Orthopedic Surgery, National Taiwan University Hospital and
Children Hospital, Taipei, Taiwan
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