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An assessment of deterioration of colour vision, contrast sensitivity and phorias as a result of hypoxia in persons resident at altitude

The altitude at which oxygen supplementation should commence to be administered to aircrew in South Africa, flying in unpressurised aircraft is 12,000 feet. Above that altitude effects of reduced tissue oxygen content (hypoxia) become significant. Vision is particularly sensitive to hypoxia, and it was decided to test visual parameters at 12,000 feet to see if there were any subtle changes which might impair flight safety. It this were so, the level at which oxygen supplementation should commence would have to be lowered. The visual parameters to be assessed, all important in aviation, were colour vision, contrast sensitivity, and the presence of phorias (potential squints). 37 Healthy volunteers had these parameters assessed in an altitude chamber at ground level, 8,000 feet and 12,000 feet. Analysis of the results revealed no clinically significant degradation of vision at 12,000 feet, and it was concluded that the present altitude at which oxygen supplementation should begin (12,000 feet) is appropriate. It was advised that further testing should take place in subjects based at sea level. / Dissertation (MSc)--University of Pretoria, 2006. / School of Health Systems and Public Health (SHSPH) / Unrestricted

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:up/oai:repository.up.ac.za:2263/26401
Date01 February 2005
CreatorsMacFarlane, Campbell
ContributorsLe Roux, C.G.J.
Source SetsSouth African National ETD Portal
Detected LanguageEnglish
TypeDissertation
Rights© 2003, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.

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