A method for identifying color vision deficiency malingering

Purpose: To propose a new test to identify color vision deficiency malingering.

Methods: An online survey was distributed to 130 truly color vision deficient participants and 160 participants willing to simulate color vision deficiency. The survey contained three sets of six color-adjusted versions of the standard Ishihara color plates each, as well as one set of six control plates. The plates that best discriminated both participant groups were selected for a "balanced" test emphasizing both sensitivity and specificity. A "specific" test that prioritized high specificity was also created by selecting from these plates. Statistical measures of the test (sensitivity, specificity, and Youden index) were assessed at each possible cut-off threshold, and a receiver operating characteristic (ROC) function with its area under the curve (AUC) charted.

Results: The redshift plate set was identified as having the highest difference of means between groups (-58%, CI: -64 to -52%), as well as the widest gap between group modes. Statistical measures of the "balanced" test show an optimal cut-off of at least two incorrectly identified plates to suggest malingering (Youden index: 0.773, sensitivity: 83.3%, specificity: 94.0%, AUC of ROC 0.918). The "specific" test was able to identify color vision deficiency simulators with a specificity of 100% when using a cut-off of at least two incorrectly identified plates (Youden index 0.599, sensitivity 59.9%, specificity 100%, AUC of ROC 0.881).

Conclusions: Our proposed test for identifying color vision deficiency malingering demonstrates a high degree of reliability with AUCs of 0.918 and 0.881 for the "balanced" and "specific" tests, respectively. A cut-off threshold of at least two missed plates on the "specific" test was able to identify color vision deficiency simulators with 100% specificity.