2024, Volume 30, Issue 2
THE EFFECT OF NORMOBARIC HYPOXIA ON RETINAL SENSITIVITY: A PERIMETRIC STUDY UNDER SIMULATED ALTITUDE OF 4500 M ABOVE SEA LEVEL
KAROL STASIAK1, RAFAŁ LEWKOWICZ2, MAREK PROST1
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1Department of Ophthalmology, Military Institute of Aviation Medicine
2Department of Simulator Studies and Aeromedical Training, Military Institute of Aviation Medicine
Autor korenspondencyjny: RAFAŁ LEWKOWICZ; Department of Simulator Studies and Aeromedical Training, Military Institute of Aviation Medicine; email: rlewkowicz@wiml.waw.pl
Streszczenie
Introduction: Hypoxia is an important factor affecting the function of the nervous system, including the visual pathway. The aim of this study was to evaluate changes in retinal sensitivity to light stimuli under normobaric hypoxia corresponding to an altitude of 4500 m above sea level.
Methods: The study involved 26 healthy men (mean age: 20.96 years). Participants breathed a gas mixture containing 9.6% O₂ for 30 minutes (equivalent to staying at an altitude of 4500 m above sea level). Retinal sensitivity was assessed using computerized perimetry with five strategies covering the visual field from the center to 90 degrees, prior to hypoxia exposure, and at the 10th and 25th minute of hypoxia exposure. During the test, peripheral blood oxygen saturation (SpO₂) and heart rate were monitored.
Results: After 25 minutes of exposure to normobaric hypoxia (mean SpO₂: 81.4%), all tests covering the central visual field (0-25 degrees) showed a statistically significant decrease in retinal sensitivity, particularly in the Blue-on-Yellow test, with an average decline of −1.91 dB. The most pronounced changes were observed in the inferotemporal and inferonasal quadrants (up to −2.23 dB). In the 30-60 degree range no significant changes were observed.
Conclusions: Normobaric hypoxia leads to decreased retinal sensitivity, particularly in the central visual field and in the short-wavelength sensitive cone pathway. These results may have operational significance in military aviation, where hypoxia coexists with psychophysical workload, although they require cautious interpretation.
Słowa kluczowe
normobaric hypoxia, retinal sensitivity, visual field, aviation physiology