Color codes in VDT displays often contain sets of colors that are
confusing to individuals with color-vision deficiencies. The purpose of
this study is to determine whether individuals with color-vision
deficiencies (color defectives) can perform as well as
individuals without color-vision deficiencies (color normals)
on a colored VDT display used in the railway industry and to determine
whether clinical color-vision tests can predict their performance. Of
the 52 color defectives, 58% failed the VDT test. The kappa
coefficients of agreement for the Farnsworth D-15, Adams desaturated
D-15, and Richmond 3rd Edition HRR PIC diagnostic plates were
significantly greater than chance. In particular, the D-15 tests have a
high probability of predicting who fails the practical test. However,
all three tests had an unacceptably high false-negative rate
(9.5–35%); so that a practical test is still needed.