Abstract

DO.23.07

Colorimetric analysis of three editions of the Velhagen-Broschmann pseudoisochromatic color plates

Kuchenbecker J.¹, Schultz S.², Behrens-Baumann W.^3
1Augenklinik, HELIOS Klinikum Berlin-Buch; ²Insitut für Psychologie, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale; ³Universitäts-Augenklinik Magdeburg

Objective: Chromatic variations of different editions of pseudoisochromatic plates are possible due to printing or fading over time. The diagnostic quality of various plates of an edition is also very different.
Methods: We analyzed colorimetric characteristics of three different editions of Velhagen-Broschmann pseudoisochromatic plates (30^th edition printed in 1995, 31^st edition printed in 1997 and 32nd edition printed in 2000). 112 colored dots of 18 plates were chosen from each edition. We measured RGB and CIE XYZ values using a spectrophotometer. Differences between corresponding dots of different editions were determined using the CIE color difference formula. Furthermore, optimal confusion lines of dichromats for the u’v’-data of each plate and the relative luminance of a target compared to its background in terms of the Weber contrast were analyzed.
Results: Mean ΔE across editions was moderate with 3.3 (±1.7). We could not find a systematic shift of CIE L*a*b* values with age. Deviatons of targets from dichromatic confusion lines were large and luminance contrast of symbol and background was high in some color plates. Comparison with psychophysical data showed that such color plates are good detectable by color deficient observers.
Conclusions: There was no chromatic variation between editions due to fading over time. The test construction of some Velhagen-Broschmann pseudoisochromatic plates should be improved for a better diagnostic quality. We recommend the manufacturers of the Velhagen-Broschmann pseudoisochromatic test to publish the colorimetric data of each plate for potential internal and external quality control.

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