Vergleich zweier Screening-Verfahren zur Farbsinnprüfung: Ishihara-Tafeln vs. digitales Replikat

Abstract

Comparison of two screening procedures for testing colour perception: Ishihara plates vs. digital replication Purpose: The study was designed to prove that the digitalized colour vision test integrated into the Optovist II is equivalent to the traditional Ishihara colour charts. Methods: Colour vision was tested with a sample size of 220 subjects (36 colour-deficient) and three different test methods. A new version of the Ishihara tablets was used under standard lighting conditions and at a distance of about 75 cm. The colour vision test (digitalized Ishihara plates) of a calibrated Optovist II (Vistec AG, Olching) and an HMC anomaloscope (Oculus Optikgeräte GmbH, Wetzlar) were also used. The first 17 plates of the Ishihara test were assessed in both the Ishihara colour vision test and the Optovist II, because the plates contain 18–24 lines that are not suitable for testing in the vision-testing device. Results: The test subject was classified as colour-deficient after two false readings of the pseudoisochromatic plates. The Ishihara plates provided the correct result in 200 subjects compared to the gold standard anomaloscope. In contrast, the Optovist II rated correctly in a total of 202 subjects. In the case of the Ishihara plates, 17 persons with normal colour vision were identified as having a colour deficiency, and three colour-deficient persons were classified as colour-competent. The Optovist II classified 16 colourcompetent persons as colour-deficient, and two colour-deficient persons as colour-competent. In addition, it was possible to test for equivalence using the McNemar test and to verify this. Conclusion: The two test methods should be considered equivalent. Both methods – Ishihara plates and their digital replica in the Optovist II – should be used exclusively as a screening method. A test with the anomaloscope should be performed for the final diagnosis. Keywords: Ishihara colour vision test – pseudoisochromatic panels – color vision – anomaloscope – digital colour vision test