Purchase this article with an account.
P. Moradi, L. Membrey, H. Sheth, A. Laidlaw; The Effect of Refractive Blur on Colour Vision Evaluated Using the Cambridge Colour Contrast Test, the Ishihara Pseudoisochromatic Plates and the Farnsworth Munsell 100 Hue Test . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4748.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: To investigate the effect of refractive blurr on three types of colour vision testing. Methods: Normal subjects were recruited who were within 1 dioptre of emmetropia and had no history of ocular disease and no history or family history of colour vision defect. They underwent three types of colour vision testing; the first 17 of the Ishihara Pseudoisochromatic Plates (IPP), the Farnsworth Munsell 100 Hue (FM) test and the Cambridge Colour Contrast Trivector (CCCT) test. Each test was done with 4 level of refractive blur; 0 dioptres, +1 dioptre, +3 dioptres and +6 dioptres. These were added to the patients emmatropic prescription in combination with the appropriate level of near addition for the testing distance and the tests were carried out in random order. Results: Seven subjects were recruited. There were 3 males and 4 females with median age of 28.6 (IQ range 25 to 30). The median refractive error was –0.25 (IQ range –0.5 to +0.13). All subjects correctly identified all 17 IPPs with all levels of refractive blur. The median square root of the total error score on the FM test was 10.3 (IQ range 8.2 to 10.9) with no refractive blur and there was no significant effect of +1 dioptres. This increased to 11.5 (IQ range 9.4 to 11.8) with + 3 dioptres blur (p=0.02) and 13.8 (IQ range 13.2 to 14.8) with + 6 dioptres (p=0.02). The median protan, deutan and tritan thresholds on the CCCT test were 61.0 (IQ range 57.0 to 73.8), 68.0 (IQ range 64.3 to 75.8) and 129.5 (IQ range 111.5 to 148.0) respectively. There was no significant effect of either the +1 dioptres blur or the +3 dioptres blur. With the +6 diptres blur these thresholds increased to 105.0 (IQ range71.8 to 173.0) (p=0.03), 150.0 (IQ range 111.3 to 181.3) (p=0.03) and 277.5 (IQ range 241.0 to 336.8) (p=0.03) respectively. Conclusions: The Ishihara Pseudoisochromatic Plates test appears to be very robust to the effects of refractive blur with no effects seen with a +6 dioptre lens added to the near correction. The Cambridge Colour Contrast test is also robust to refractive blur with significant effects seen only above +3 dioptres. The Farnsworth Munsell 100 Hue test appears to be more susceptible with significant effects seen at +3 dioptres blur, although these effects may exagerated as these subjects may not be completely relaxing thier accomodation for near. In summary these colour vision tests appear to be robust to the effects of refractive blur up to approximately +3 dioptres.
This PDF is available to Subscribers Only