Does the Farnsworth D15 test predict the ability to name colours?

Area of Science:

• Ophthalmology
• Optometry
• Color Vision Science

Background:

• The Farnsworth D15 test categorizes color vision deficiency (severe/moderate) and is used for patient advice and occupational selection.
• Its utility relies on the assumption that passing the test correlates with recognizing surface color codes.

Purpose of the Study:

• To investigate the correlation between Farnsworth D15 test performance and the ability to name surface colors.
• To determine if passing the D15 test reliably predicts accurate surface color naming.

Main Methods:

• 102 individuals with abnormal color vision (aged 11-65) named colors from fabric, paint, and thread samples in large and small formats.
• Errors were compared to an age-matched control group with normal color vision.

Main Results:

• Correlations between the D15 color confusion index and color naming errors were 0.62 (large stimuli) and 0.73 (small stimuli).
• The D15 test showed moderate sensitivity and specificity in identifying individuals with significant color naming errors.
• A Nagel anomaloscope range <35 units demonstrated similar predictive performance.

Conclusions:

• Approximately 40% of individuals with abnormal color vision can correctly name main colors under good visibility.
• The D15 test is an imperfect predictor for accurate surface color naming, suitable for general counseling but not sole occupational screening.
• For critical color-coding occupations, avoiding individuals with abnormal color vision may be necessary due to the absence of a perfect predictive test.