Yang Yiquan, Xie Yuan, Sun Yunxiao, Cao Kai, Li Shuning, Fan Sujie, Huang Lu, Wu Shizheng, Wang Ningli
Beijing Key Laboratory of Ophthalmology and Visual Sciences, Beijing Tongren Eye Center, Beijing Institute of Ophthalmology, Beijing Tongren Hospital of Capital Medical University, Beijing, China.
Department of Ophthalmology, The Third Hospital of Handan (Handan City Eye Hospital), Handan, China.
Front Physiol. 2019 Nov 6;10:1366. doi: 10.3389/fphys.2019.01366. eCollection 2019.
High altitude, characterized by hypobaric hypoxia, low temperature, and intensive ultraviolet radiation, is identifiably one of the examples of scientific enquiry into aviation and space analogs. However, little is known about the ocular physiological response, especially intraocular pressure (IOP) changes at high altitude. This study aimed to systematically review of high altitude exposure on IOP for healthy lowlanders with unoperated eyes. A comprehensive systematic literature search was conducted in the electronic databases until September 1st, 2019. A meta-analysis was performed following the preferred reporting items for systematic review and meta-analysis statement (PRISMA). We systematically searched the studies conducted over 2,000 m above sea level (a.s.l) in healthy lowlanders with measurements of IOP. Meta-analyses (random effect model and heterogeneity tests), subgroup analyses (altitude, duration, type, and pattern of exposure), sensitivity analysis, funnel plot, Begger's and Egger's test for publication bias were performed. Quality assessment was conducted using the Newcastle-Ottawa scale. The meta-analysis was registered in the PROSPERO database (CRD42019136865). Of 9595 publications searched, 20 publications ( = 745) qualified for inclusion, with non-significant decrease in overall IOP [standardized mean difference (SMD): 0.14, 95% CI: -0.12-0.40; = 0.30] with high heterogeneity ( < 0.001, = 82%). However, subgroup analyses revealed significant decrease of IOP at high altitude of 3,000-5,500 m a.s.l (SMD: 0.57, 95% CI: 0.07-1.06; = 0.03) whereas increase of IOP at extreme altitude of over 5,500 m a.s.l (SMD: -0.34, 95% CI: -0.61-0.06; = 0.02). And the duration of exposure more than 72 hours (h) was likely to induce a decrease of IOP bordering on statistical significance at the 5% level (SMD: 1.29, 95% CI: 0.02-2.56; = 0.05). Simultaneously, we also observed significant decrease of IOP for active exposure (e.g., physical activity and hiking, SMD: 0.81, 95% CI: 0.05-1.57; = 0.04). Our analysis shows exposure to the altitude over 3,500 m a.s.l, duration of exposure more than 72 h and active exposure pattern may have modest, but significant effects on IOP. The higher altitude, the duration of exposure as well as physical activity seem to play crucial roles in the effects of high-altitude exposure on IOP.
高海拔地区具有低压缺氧、低温和高强度紫外线辐射的特点，是航空和太空模拟科学研究的典型例子之一。然而，人们对眼部生理反应知之甚少，尤其是高海拔地区的眼压（IOP）变化。本研究旨在系统回顾高海拔暴露对未手术的健康低地人的眼压的影响。在电子数据库中进行了全面的系统文献检索，直至2019年9月1日。按照系统评价和荟萃分析报告规范（PRISMA）进行荟萃分析。我们系统检索了在海拔2000米以上对健康低地人进行的眼压测量研究。进行了荟萃分析（随机效应模型和异质性检验）、亚组分析（海拔、持续时间、暴露类型和模式）、敏感性分析、漏斗图、用于发表偏倚的Begger检验和Egger检验。使用纽卡斯尔-渥太华量表进行质量评估。该荟萃分析已在PROSPERO数据库（CRD42019136865）中注册。在检索的9595篇出版物中，20篇出版物（n = 745）符合纳入标准，总体眼压无显著下降[标准化平均差（SMD）：0.14，95%置信区间：-0.12 - 0.40；P = 0.30]，异质性高（I² < 0.001，τ² = 82%）。然而，亚组分析显示，在海拔3000 - 5500米的高海拔地区眼压显著下降（SMD：0.57，95%置信区间：0.07 - 1.06；P = 0.03），而在海拔超过5500米的极端高海拔地区眼压升高（SMD：-0.34，95%置信区间：-0.61 - 0.06；P = 0.02）。暴露持续时间超过72小时（h）可能在5%水平上导致眼压下降接近统计学显著性（SMD：1.29，95%置信区间：0.02 - 2.56；P = 0.05）。同时，我们还观察到主动暴露（如体育活动和徒步旅行）时眼压显著下降（SMD：0.81，95%置信区间：0.05 - 1.57；P = 0.04）。我们的分析表明，暴露于海拔超过3500米、暴露持续时间超过72小时和主动暴露模式可能对眼压有适度但显著的影响。海拔越高、暴露持续时间以及体育活动似乎在高海拔暴露对眼压的影响中起关键作用。
