[Colour comparison tests in unilateral optic neuropathies].

AIM OF THE STUDY

Colour comparison tests are a subjective supplement to the swinging flashlight test. We have investigated the specificity and sensitivity, compared 3 exactly defined different colours (red, green, blue), and looked for age relationships.

METHOD

101 patient with various unilateral optic neuropathies were compared to 103 age-correlated healthy controls in randomised order by letting the patient evaluate red, green and blue colour charts of 5.5 cm diameter.

RESULTS

The area under the receiver operator characteristics curve was 0.804 for red, 0.821 for green and 0.789 for blue, and for any of the 3 colours 0.835 (at least one colour was seen differently). Best results were obtained when even small differences in colour perception were considered as pathological. 29 healthy controls perceived colours differently in both eyes, 24 of those being older than 50 years. The specificity decreased with age, was significant for green and red, not for blue.

DISCUSSION

There were no significant differences between the 3 colours in all age groups. Evaluation of more than one colour does not increase the sensitivity significantly. Even small differences have to be considered as pathological to obtain the highest possible sensitivity. Test specifity decreases with age.