PURPOSE. The accurate detection and recognition of cyanosis is known the be dependent on lighting. There are anecdotal reports of colour vision deficient medical practitioners (particularly deuteranopes) having difficulty in recognising cyanosis. Given a thorough understanding of the colour changes in oxygenated blood has led to a better understanding of the lighting needs for hospitals, this project investigates the propensity for colour vision deficient observers to make mistakes with cyanotic patients and the possibilities for remediating the situation with appropriate lighting. METHOD. The spectral reflectances of blood at varying oxygenation levels has been previously reported (Dain et al, 1998). These data were used to plot the colour change with oxygenation. The slope of the chromaticity change was compared with the slope of the protan and deutan confusion lines in the same vicinity. The analysis was acrried out with a variety of sources (including fluorescent tubes) and illuminants with correlated colour or distribution temperatures between 2656K and 6500K. Sources which created colour changes more visible to protan and deutans were sought RESULTS. The chromaticities showed a significant alignment with the confusion lines (particularly deutan). No source could be demonstrated to solve the problem or even reduce it significantly.
CONCLUSIONS. The accurate detection and recognition of cyanosis by congenital colour vision deficient medical practitioners remains a problem. There is limit possibiity of providing a light source to remediate the problem.