Operation Everest II: Lack of an Effect of Extreme Altitude on Visual Contrast Sensitivity
Abstract
Contrast sensitivity thresholds were studied during gradual ascent over 40 days to a simulated altitude of 25,000 feet in a decompression chamber. Only ambient pressure, and thus inspired oxygen pressure was varied, thereby eliminating many of the confounding effects of cold, dehydration, malnutrition and exhaustion, inevitably encountered on very high mountains. Contrast sensitivity thresholds measured by the Ginsburgh Vistech test showed no overall impairment as altitude increased. These results are in contrast to findings of other previously reported vision studies involving shorter exposures and lower altitudes than those of the present study. However, our findings can be reconciled with previous contrary results on the basis of the higher stimulus luminances used in our contrast sensitivity testing. Compared to the luminance levels involved in previously reported night vision testing, our stronger stimuli would be less likely to be affected by hypoxia. Keywords: Acclimatization; High altitude; Mountaineering.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1987
- Accession Number
- ADA177577
Entities
People
- Barbara Shukitt
- Charles S. Houston
- Edith Crohn
- John L. Kobrick
Organizations
- United States Army Research Institute of Environmental Medicine