Evaluation of a chromatometer: a new method for blue-yellow or green-red visual comparisons, and anomaly screening...

Malbrel's chromatometer is a new apparatus which allows color vision to be monitored. The aim of this study was to assess the accuracy of this new examination method.

The color vision of a patient was analyzed using a chromatometer for direct heterochromatic visual comparisons. The patient's task was to adjust, using one eye only, the brightness of a yellow (or red) window to the one of a fixed blue (or green) window. Overall, 158 patients, aged 20 to 28, took part in the experiment. First, parametric means were used to study the response distributions and the luminous effects on the responses. Second, using non-parametric means, we considered that a patient had an anomalous color vision according to the chromatometer if the response was higher than the 95th percentile or lower than 5th percentile. Third, anomalous responses were compared with the Ishihara plates and Farnsworth 28-hue responses.

The effect of a luminous stimulus on the response was significant (adjusted to the patient effect). Thus, the chromatometer appears to be a good method to analyze color vision. This apparatus was easy to use and constituted a sensitive and specific test with high negative predictive value.

The chromatometer can be used as a first-line screening test to detect color vision anomalies during ophthalmology consultations. The chromatometer can be useful in identifying early ocular disease, monitoring disease development, or checking possible iatrogenic effects of a specific treatment.