The effect of short-term hypobaric hypoxic exposure on intraocular pressure.
OBJECTIVE
To evaluate the effect of short-term hypobaric hypoxic conditions (STHC) on intraocular pressure (IOP) in healthy subjects.


METHODS
The study group was comprised of 30 healthy participants (60 eyes) with a mean age of 24.8 years. IOP was measured with a Tono-Pen XL tonometer at ground level (792 m above sea level, prehypoxic) during hypobaric hypoxic exposure (equivalent to 9144 m) and at ground level again after this exposure (post-hypoxic). For each condition, the mean of 3 consecutive measurements of IOP was calculated. In each condition, central corneal thickness was also measured.


RESULTS
IOP in the hypobaric hypoxic condition (18.23 +/- 2.84 mmHg) was significantly greater than IOP in both the prehypoxic condition (16.52 +/- 2.84 mmHg) (p < 0.001) and the post-hypoxic condition (17.02 +/- 2.52 mmHg) (p < 0.01). When corrected for hypoxia-related changes in CCT, IOP under hypobaric hypoxic conditions was still greater than IOP in both the prehypoxic and post-hypoxic conditions. There was no significant difference between IOP levels in the prehypoxic and post-hypoxic conditions (p > 0.05).


CONCLUSIONS
STHC caused a significant increase in IOP in healthy participants. But this significant increase in IOP cannot be solely explained by a CCT-related overestimation error due to the increase in CCT. Individuals with IOP-related disorders such as glaucoma should be cautious when facing potential exposure to hypobaric hypoxic conditions.
Karadag
Remzi
R
Department of Ophthalmology, Eskisehir Military Hospital, Eskisehir, Turkey. drrkaradag@yahoo.com
Sen
Ahmet
A
Golemez
Haydar
H
Basmak
Hikmet
H
Yildirim
Nilgun
N
Karadurmus
Nuri
N
Koseoglu
Ercan
E
Akin
Ahmet
A
D000328:Adult; D000531:Altitude; D001273:Atmosphere Exposure Chambers; D001274:Atmospheric Pressure; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008889:Military Personnel; D010101:Oxygen Consumption / Q000502:physiology; D014065:Tonometry, Ocular