Frequencies of different types of colour vision defects in the netherlands

Abstract

Two different population samples in Holland-one consisting of 1,093 boys from a technical school and the other of 493 male and 416 female students-were analysed foi the presence of red-green colour vision defects. A total percentage of 7.3 for the male population was found. Based on the combined results of the Ishihara and HRR pseudo-isochromatic plates, the Farnsworth 15-hue test and the anomaloscope, a subdivison of the deuteranomalous individuals into 3 subgroups is made. It is suggested that the differences between these groups may be genetic in nature and that the actual number of different genetic entities may still be greater. © 1978 S. Karger AG, Basel.