Article Text

Download PDFPDF
Effects on colour discrimination during long term exposure to high altitudes on Mt Everest
  1. Gabriel Willmann1,2,
  2. Iliya V Ivanov3,4,
  3. Manuel D Fischer3,
  4. Sukhamay Lahiri1,
  5. Rohit K Pokharel5,
  6. Annette Werner3,
  7. Tejvir S Khurana1
  1. 1Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, USA
  2. 2Eye Hospital, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
  3. 3Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
  4. 4McGill Vision Research, Department. of Ophthalmology, McGill University, Montreal, Quebec, Canada
  5. 5Department of Orthopedics, Tribhuvan University, Kathmandu, Nepal
  1. Correspondence toGabriel Willmann, Eye Hospital, Centre for Ophthalmology, University of Tübingen, 72076 Tübingen, Schleichstrasse 12–16, Germany; gabriel.willmann{at}


Aim To investigate changes in colour discrimination as a result of chronic hypoxic exposure induced by extreme altitudes (above 8000 m) during an expedition to Mt Everest.

Methods Colour discrimination thresholds for tritan, protan and deutan axes were measured extensively in two male participants (four eyes) during an expedition to Mt Everest, using a quantitative, computer controlled psychophysical colour vision test (modified version of the Cambridge Colour Test). The tests were carried out over a period of 54 days at altitudes of 1300 m, 3450 m, 4410 m, 5060 m, 5300 m, 6450 m, 7200 m and 8000 m.

Results Colour vision tests 1 week before and 6 months after the expedition indicated normal colour discrimination in both participants. With increasing altitude, colour discrimination thresholds were found to rise, predominantly for the tritan (blue) axes in both observers. Deutan (green) thresholds were minimally elevated at high altitude, whereas protan (red) was altered in one observer. Tritan colour discrimination thresholds decreased as a function of time spent at a given altitude and normalised upon return to low altitude.

Conclusions Chronic hypoxia induced by high altitude exposure transiently affects colour discrimination, in particular tritan axis discrimination. Decreased tritan discrimination is partly reversible upon physiological adaptation to high altitude and completely normalised upon return to low altitude.

  • Colour vision
  • hypoxia
  • high altitude
  • tritan axis
  • Cambridge Colour Test
  • Psychophysics

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • TSK and AW contributed equally to this study. S Lahiri died in May 2009.

  • Funding Funded in part by grants from World Anti-Doping Agency (WADA) to SL and TSK.

  • Competing interests None.

  • Ethics approval Ethics approval was provided by the Nepalese Health Research Council (NHRC), Kathmandu, Nepal.

  • Provenance and peer review Not commissioned; externally peer reviewed.

Linked Articles

  • At a glance
    Harminder S Dua Arun D Singh