The role of small-field tritanopia in two measures of colour vision.
The present work extends the findings of previous efforts examining the comparability of current colour-screening tests. Several popular tests are shown to differ greatly in the performance exhibited by colour-normal observers as well as in their differential sensitivity to experimental manipulations of viewing duration and viewing distance. Those tests designed to identify yellow-blue dichromacy are especially sensitive to the manipulation of viewing distance, which is interpreted as reflecting 'small-field tritanopia' and the asymmetry in retinal density of the three cone types. These findings are discussed in terms of factors that influence the comparability of current colour-screening devices and the particular need for close adherence to standardized conditions with such instruments.
Tuck
J P
JP
Department of Psychology, Villanova University, PA 19085.
Long
G M
GM
D003118:Color Perception / Q000502:physiology*; D003119:Color Perception Tests / Q000592:standards*; D003117:Color Vision Defects / Q000175:diagnosis; D006801:Humans; D011897:Random Allocation