Purpose: Individuals with congenital color deficiencies show a large inter-observer variation in performing color related tasks. One such task is interpreting color codes used in VDT displays. The aim of this study is to determine if Ishihara, HRR plates, Farnsworth D-15, Adams D-15 and CN Lantern can predict the performance on a VDT color naming task.

Methods: 100 color-normals and 52 color-defectives participated in the study. Pass/Fail criteria for the color naming task was established based on number and types of color normal errors.

Results: Discriminant analysis was performed to compare the clinical tests with the task. HRR plates, Farnsworth D-15, Adams D-15 and CN Lantern were significant predictors according to the model. Of all the clinical tests, the Farnsworth D-15 test was the best predictor of performance on the practical test. The sensitivity and specificity was 0.75 and 0.92 respectively.

Conclusions: Certain clinical tests are reasonable predictors for determining who can adequately identify certain VDT colors. These tests are generally used to diagnose moderate to severe color vision defects. The Farnsworth- D-15 test was the best predictor of the practical test. However, it was not perfect. Whether the Farnsworth- D-15 is sufficient for occupational purposes depends on the critical safety issues.