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New insights into changes in corneal thickness in healthy mountaineers during a very-high-altitude climb to Mount Muztagh Ata


Bosch, M M; Barthelmes, D; Merz, T M; Knecht, P B; Truffer, F; Bloch, K E; Thiel, M A; Petrig, B L; Turk, A J; Schoch, O D; Hefti, U; Landau, K (2010). New insights into changes in corneal thickness in healthy mountaineers during a very-high-altitude climb to Mount Muztagh Ata. Archives of Ophthalmology, 128(2):184-189.

Abstract

OBJECTIVE: To investigate the effect of very high altitude and different ascent profiles on central corneal thickness (CCT). METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

OBJECTIVE: To investigate the effect of very high altitude and different ascent profiles on central corneal thickness (CCT). METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Ophthalmology Clinic
04 Faculty of Medicine > Center for Integrative Human Physiology
04 Faculty of Medicine > University Hospital Zurich > Clinic for Pneumology
Dewey Decimal Classification:570 Life sciences; biology
610 Medicine & health
Language:English
Date:2010
Deposited On:04 Jul 2010 14:40
Last Modified:05 Apr 2016 14:10
Publisher:American Medical Association
ISSN:0003-9950
Publisher DOI:10.1001/archophthalmol.2009.385
PubMed ID:20142540
Permanent URL: http://doi.org/10.5167/uzh-34751

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