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Pupillary light reaction during high altitude exposure
Maximilian Schultheiss1, Kai Schommer2, Andreas Schatz3
1Center of Ophthalmology, University of Tübingen, Tübingen, Germany.
Plos One
|February 8, 2014
Summary
High altitude exposure significantly alters pupillary light reactions, affecting pupil size and constriction velocity. These changes, however, do not correlate with acute mountain sickness (AMS) severity.
Area of Science:
- Ophthalmology
- Altitude Physiology
- Human Physiology
Background:
- High altitude exposure presents physiological challenges.
- Pupillary light reactions are crucial indicators of neurological and ocular function.
- Understanding these reactions at altitude is vital for assessing physiological stress.
Purpose of the Study:
- To quantify pupillary light reaction changes during high altitude exposure using the Compact Integrated Pupillograph (CIP).
- To investigate correlations between altered pupil dynamics and acute mountain sickness (AMS) severity.
- To contribute to the Tübingen High Altitude Ophthalmology (THAO) study.
Main Methods:
- Quantified pupil dynamics (diameter, amplitude, latency, velocity) in 14 volunteers at baseline (341m) and high altitude (4559m).
- Assessed AMS scores, oxygen saturation, and heart rate for correlations with pupil parameters.
- Utilized intra-individual normalized values and 95% confidence intervals for statistical analysis.
Main Results:
- Initial pupil diameter significantly reduced at high altitude (p<0.05).
- Amplitude and contraction velocity of light reaction significantly increased at high altitude (p<0.05).
- No significant changes in latency; pupil parameter changes did not correlate with AMS scores.
Conclusions:
- Key pupillary light reaction parameters are significantly altered by high altitude exposure.
- Hypothesized causes include high altitude hypoxia and associated factors like fatigue.
- Observed pupillary changes were independent of acute mountain sickness severity.
