Intraocular pressure changes during high-altitude acclimatization.
BACKGROUND
To evaluate the relationship between hypobaric hypoxia acclimatization and intraocular pressure (IOP) during ascent, acclimatization, and descent between 2286 m and 5050 m.


METHODS
The following acclimatization-indicative physiological parameters were compared daily with IOP changes in eight healthy climbers of the 2003 Greek Karakorum expedition in altitude stages between 500 m and 5050 m: hemoglobin oxygen saturation (PO2), resting heart rate, blood pressure, retinal findings, and the Lake Louise score for acclimatization grading.


RESULTS
IOP decreased significantly in the ascent phase (0.58 mmHg/100 m) and recovered (0.71 mmHg/100 m) during acclimatization and descent. A direct proportional correlation between decreases in PO2 and IOP was evaluated. Arterial blood pulse and pressure increased during acclimatization, while IOP decreased. No retinal hemorrhages were observed in well-acclimatized and incompletely acclimatized climbers.


CONCLUSIONS
Every new active exposure to hypobaric hypoxia in the ascent phase induced a decrease in the IOP parallel to the PO2 decrease and to the level of acclimatization. The results from our study suggest that IOP changes are related to hypoxia-induced respiratory alkalosis and acclimatization stage, which could be used as a simple mobile screening test for acclimatization level to reveal acute mountain sickness and its severe consequences.
Pavlidis
Mitrofanis
M
Department of Experimental Ophthalmology, University Eye Hospital of Münster, Domagkstrasse 15, 48149, Münster, Germany. pavlidis@uni-muenster.de
Stupp
Tobias
T
Georgalas
Ilias
I
Georgiadou
Evi
E
Moschos
Michail
M
Thanos
Solon
S
D000064:Acclimatization / Q000502:physiology*; D000328:Adult; D000368:Aged; D000472:Alkalosis, Respiratory / Q000503:physiopathology*; D000531:Altitude; D000532:Altitude Sickness / Q000175:diagnosis; D001274:Atmospheric Pressure; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010313:Partial Pressure