Abstract

SA.18.02

Impact of coloured contact lenses on colour discrimination

Annette Walter, Michael Schuerer, Holger Bruenner, Achim Langenbucher
Institut für medizinische Physik, Universität Erlangen-Nürnberg, Erlangen

Objective: For contrast enhancement, orange and yellow coloured contact lenses are advertised for improvements of vision while skiing as well as promising increased contrast sensitivity for motorists driving under froggy or misty weather conditions. But this claim lacks objective confirmation by means of proper measurement techniques. The change in colour perception due to the use of coloured contact lenses can be measured with a novel measurement technique and is analyzed objectively on 13 subjects.
Methods: The apparatus employed in this investigation was designed to provide a matching test fulfilling the requirements of DIN5033. The determination of colour discriminance thresholds was performed with an adaptive measurement procedure on 5 axis with and without colored contact lenses around a central colour yellow (x = 0.4664 and y =0.4528). The colour discrimination thresholds in each axis and subject were transformed to the CIE 1976 USC chromaticity diagram. Macadam’s ellipses were fitted through the thresholds of each single person respectively by using a last squares method. The ellipses for each specific filter media were averaged over all 13 subjects and the ellipse centers were shifted to the origin to analyze differences in colour discrimination ellipses in the red – green as well in blue – yellow direction.
Results: It could be shown, that ellipses with coloured contact lenses decreased in sizes. Measurements with yellow coloured contact lenses show a significant decrease of colour discrimination thresholds in all directions of the colour space, while the orientation of the ellipse compared with the ellipses measured for free sight remained. The impact of orange coloured contact lenses on colour vision is, that a significant increase of colour perception occurred at the yellow – red as well as at the cyan range and a significant decrease was found at the yellow – green as well as at the violet range.
Conclusions: This novel setup enables an objective determination of changes in colour perception by means of coloured contact lenses objectively. From color discrimination thresholds measured with and without coloured contact lenses we conclude that the discrimination of objects based on colour differences with coloured contact lenses is increased. The impact of surrounding colours and neutral adaptation colour on the discrimination thresholds will be subject to further studies.

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