Bosch Martina Monika, Barthelmes Daniel, Merz Tobias Michael, Knecht Pascal Bruno, Truffer Frederic, Bloch Konrad E, Thiel Michael A, Petrig Benno L, Turk Alexander J, Schoch Otto D, Hefti Urs, Landau Klara
Department of Ophthalmology, University Hospital Zurich, Frauenklinikstrasse 24, 8091 Zurich, Switzerland.
Arch Ophthalmol. 2010 Feb;128(2):184-9. doi: 10.1001/archophthalmol.2009.385.
To investigate the effect of very high altitude and different ascent profiles on central corneal thickness (CCT).
Twenty-eight healthy mountaineers were randomly assigned to 2 different ascent profiles during a medical research expedition to Mount Muztagh Ata (7546 m) in western China. Group 1 was allotted a shorter acclimatization time prior to ascent to 6265 m. The main outcome measure was CCT. Secondary outcome measures were oxygen saturation (SpO(2)) and symptom assessments of acute mountain sickness (cerebral acute mountain sickness score). Examinations were performed at 490, 4497, 5533, and 6265 m.
Central corneal thickness increased in both groups with increasing altitude and decreased after descent. In group 1 (with the shorter acclimatization), mean CCT increased from 537 to 572 microm. Mean CCT in group 2 increased from 534 to 563 microm (P = .048). The amount of decrease in SpO(2) paralleled the increase in CCT. There was no significant decrease in visual acuity. There was a significant correlation between CCT and cerebral acute mountain sickness score when controlled for SpO(2) and age.
Corneal swelling during high-altitude climbs is promoted by low SpO(2). Systemic delivery of oxygen to the anterior chamber seems to play a greater role in corneal oxygenation than previously thought. Adhering to a slower ascent profile results in less corneal edema. Visual acuity in healthy corneas is not adversely affected by edema at altitudes of up to 6300 m. Individuals with more acute mountain sickness-related symptoms had thicker corneas, possibly due to their higher overall susceptibility to hypoxia.
探讨极高海拔和不同上升模式对中央角膜厚度（CCT）的影响。
在中国西部慕士塔格峰（7546米）进行的一项医学研究探险中，28名健康登山者被随机分配到2种不同的上升模式。第1组在上升至6265米之前的适应时间较短。主要观察指标是CCT。次要观察指标是血氧饱和度（SpO₂）和急性高山病症状评估（脑急性高山病评分）。在490米、4497米、5533米和6265米处进行检查。
两组的中央角膜厚度均随海拔升高而增加，下降后变薄。在第1组（适应时间较短）中，平均CCT从537微米增加到572微米。第2组的平均CCT从534微米增加到563微米（P = 0.048）。SpO₂下降的幅度与CCT的增加平行。视力没有显著下降。在控制SpO₂和年龄后，CCT与脑急性高山病评分之间存在显著相关性。
低SpO₂会促使高海拔攀登期间角膜肿胀。与之前的认知相比，全身向前房输送氧气在角膜氧合中似乎发挥着更大的作用。坚持较慢的上升模式会减少角膜水肿。在海拔高达6300米时，健康角膜的水肿不会对视力产生不利影响。急性高山病相关症状较多的个体角膜较厚，可能是因为他们对缺氧的总体易感性较高。
