Central Corneal Thickness of Healthy Lowlanders at High Altitude

A Systematic Review and Meta-Analysis

Hsin Ming Liu, Chyi Huey Bai, Cher Ming Liou, Hung Yi Chiou, Chiehfeng Chen

研究成果: 雜誌貢獻文章

摘要

Purpose: Central corneal thickness, a marker of corneal hydration and metabolism, was reported to increase at high elevations. This study aimed to assess the effect of chronic high-altitude exposure on the central corneal thickness of healthy lowlanders with unoperated corneas, and determine if a relationship exists between exposure time and corneal edema formation. Materials and Methods: The PubMed, Embase, Scopus, Cochrane Library, and Airiti Library databases were searched up to 2017 January 31 for prospective cohort studies performed above 2500 m in healthy lowlanders with measurements of the central corneal thickness. Subjects with prior eye surgery, contact lens, and non-hypobaric hypoxic exposure were excluded. Results: Seven studies of 207 adults were included. The pooled effect of high-altitude exposure on the central corneal thickness for < 12 hours, 3–5 days, 6–7 days, and > 10 days was a mean difference of 13.4 (95% confidence interval: 5.1–21.6) μm with moderate heterogeneity (p < 0.05, I2 = 59%), 19.3 (95% confidence interval: 9.7–29) μm with low heterogeneity (p = 0.88, I2 = 0%), 20.4 (95% confidence interval: 10.3–30.5) μm with low heterogeneity (p = 0.73, I2 = 0%), and 30.8 (95% confidence interval: 20.4–41.2) μm with low heterogeneity (p = 0.69, I2 = 0%), respectively. Baseline differences between pre-exposure and post-exposure were not statistically significant. Regression analysis revealed a significant linear relation between high-altitude exposure time and corneal edema formation that exceeded 5% after 10 days. Conclusions: High-altitude exposure induces central corneal thickening with significant linear progression over time, whereas it takes over 10 days to reach clinical significance in healthy lowlanders with unoperated corneas, and changes in central corneal thickness are reversible after descent to lower elevations.

原文英語
頁(從 - 到)460-465
頁數6
期刊Current Eye Research
43
發行號4
DOIs
出版狀態已發佈 - 四月 3 2018

指紋

Meta-Analysis
Confidence Intervals
Corneal Edema
Cornea
Libraries
Corneal Pachymetry
Contact Lenses
PubMed
Cohort Studies
Regression Analysis
Databases
Prospective Studies

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

引用此文

Central Corneal Thickness of Healthy Lowlanders at High Altitude : A Systematic Review and Meta-Analysis. / Liu, Hsin Ming; Bai, Chyi Huey; Liou, Cher Ming; Chiou, Hung Yi; Chen, Chiehfeng.

於: Current Eye Research, 卷 43, 編號 4, 03.04.2018, p. 460-465.

研究成果: 雜誌貢獻文章

@article{038f71f4e3384053a4ff23fc5ecebc60,
title = "Central Corneal Thickness of Healthy Lowlanders at High Altitude: A Systematic Review and Meta-Analysis",
abstract = "Purpose: Central corneal thickness, a marker of corneal hydration and metabolism, was reported to increase at high elevations. This study aimed to assess the effect of chronic high-altitude exposure on the central corneal thickness of healthy lowlanders with unoperated corneas, and determine if a relationship exists between exposure time and corneal edema formation. Materials and Methods: The PubMed, Embase, Scopus, Cochrane Library, and Airiti Library databases were searched up to 2017 January 31 for prospective cohort studies performed above 2500 m in healthy lowlanders with measurements of the central corneal thickness. Subjects with prior eye surgery, contact lens, and non-hypobaric hypoxic exposure were excluded. Results: Seven studies of 207 adults were included. The pooled effect of high-altitude exposure on the central corneal thickness for < 12 hours, 3–5 days, 6–7 days, and > 10 days was a mean difference of 13.4 (95{\%} confidence interval: 5.1–21.6) μm with moderate heterogeneity (p < 0.05, I2 = 59{\%}), 19.3 (95{\%} confidence interval: 9.7–29) μm with low heterogeneity (p = 0.88, I2 = 0{\%}), 20.4 (95{\%} confidence interval: 10.3–30.5) μm with low heterogeneity (p = 0.73, I2 = 0{\%}), and 30.8 (95{\%} confidence interval: 20.4–41.2) μm with low heterogeneity (p = 0.69, I2 = 0{\%}), respectively. Baseline differences between pre-exposure and post-exposure were not statistically significant. Regression analysis revealed a significant linear relation between high-altitude exposure time and corneal edema formation that exceeded 5{\%} after 10 days. Conclusions: High-altitude exposure induces central corneal thickening with significant linear progression over time, whereas it takes over 10 days to reach clinical significance in healthy lowlanders with unoperated corneas, and changes in central corneal thickness are reversible after descent to lower elevations.",
keywords = "Altitude, central corneal thickness, corneal edema",
author = "Liu, {Hsin Ming} and Bai, {Chyi Huey} and Liou, {Cher Ming} and Chiou, {Hung Yi} and Chiehfeng Chen",
year = "2018",
month = "4",
day = "3",
doi = "10.1080/02713683.2017.1408127",
language = "English",
volume = "43",
pages = "460--465",
journal = "Current Eye Research",
issn = "0271-3683",
publisher = "Informa Healthcare",
number = "4",

}

TY - JOUR

T1 - Central Corneal Thickness of Healthy Lowlanders at High Altitude

T2 - A Systematic Review and Meta-Analysis

AU - Liu, Hsin Ming

AU - Bai, Chyi Huey

AU - Liou, Cher Ming

AU - Chiou, Hung Yi

AU - Chen, Chiehfeng

PY - 2018/4/3

Y1 - 2018/4/3

N2 - Purpose: Central corneal thickness, a marker of corneal hydration and metabolism, was reported to increase at high elevations. This study aimed to assess the effect of chronic high-altitude exposure on the central corneal thickness of healthy lowlanders with unoperated corneas, and determine if a relationship exists between exposure time and corneal edema formation. Materials and Methods: The PubMed, Embase, Scopus, Cochrane Library, and Airiti Library databases were searched up to 2017 January 31 for prospective cohort studies performed above 2500 m in healthy lowlanders with measurements of the central corneal thickness. Subjects with prior eye surgery, contact lens, and non-hypobaric hypoxic exposure were excluded. Results: Seven studies of 207 adults were included. The pooled effect of high-altitude exposure on the central corneal thickness for < 12 hours, 3–5 days, 6–7 days, and > 10 days was a mean difference of 13.4 (95% confidence interval: 5.1–21.6) μm with moderate heterogeneity (p < 0.05, I2 = 59%), 19.3 (95% confidence interval: 9.7–29) μm with low heterogeneity (p = 0.88, I2 = 0%), 20.4 (95% confidence interval: 10.3–30.5) μm with low heterogeneity (p = 0.73, I2 = 0%), and 30.8 (95% confidence interval: 20.4–41.2) μm with low heterogeneity (p = 0.69, I2 = 0%), respectively. Baseline differences between pre-exposure and post-exposure were not statistically significant. Regression analysis revealed a significant linear relation between high-altitude exposure time and corneal edema formation that exceeded 5% after 10 days. Conclusions: High-altitude exposure induces central corneal thickening with significant linear progression over time, whereas it takes over 10 days to reach clinical significance in healthy lowlanders with unoperated corneas, and changes in central corneal thickness are reversible after descent to lower elevations.

AB - Purpose: Central corneal thickness, a marker of corneal hydration and metabolism, was reported to increase at high elevations. This study aimed to assess the effect of chronic high-altitude exposure on the central corneal thickness of healthy lowlanders with unoperated corneas, and determine if a relationship exists between exposure time and corneal edema formation. Materials and Methods: The PubMed, Embase, Scopus, Cochrane Library, and Airiti Library databases were searched up to 2017 January 31 for prospective cohort studies performed above 2500 m in healthy lowlanders with measurements of the central corneal thickness. Subjects with prior eye surgery, contact lens, and non-hypobaric hypoxic exposure were excluded. Results: Seven studies of 207 adults were included. The pooled effect of high-altitude exposure on the central corneal thickness for < 12 hours, 3–5 days, 6–7 days, and > 10 days was a mean difference of 13.4 (95% confidence interval: 5.1–21.6) μm with moderate heterogeneity (p < 0.05, I2 = 59%), 19.3 (95% confidence interval: 9.7–29) μm with low heterogeneity (p = 0.88, I2 = 0%), 20.4 (95% confidence interval: 10.3–30.5) μm with low heterogeneity (p = 0.73, I2 = 0%), and 30.8 (95% confidence interval: 20.4–41.2) μm with low heterogeneity (p = 0.69, I2 = 0%), respectively. Baseline differences between pre-exposure and post-exposure were not statistically significant. Regression analysis revealed a significant linear relation between high-altitude exposure time and corneal edema formation that exceeded 5% after 10 days. Conclusions: High-altitude exposure induces central corneal thickening with significant linear progression over time, whereas it takes over 10 days to reach clinical significance in healthy lowlanders with unoperated corneas, and changes in central corneal thickness are reversible after descent to lower elevations.

KW - Altitude

KW - central corneal thickness

KW - corneal edema

UR - http://www.scopus.com/inward/record.url?scp=85038636632&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85038636632&partnerID=8YFLogxK

U2 - 10.1080/02713683.2017.1408127

DO - 10.1080/02713683.2017.1408127

M3 - Article

VL - 43

SP - 460

EP - 465

JO - Current Eye Research

JF - Current Eye Research

SN - 0271-3683

IS - 4

ER -