Statistical demonstration of minor colour vision abnormalities.

Analysis of the results from 94 male and 94 female young normal trichromats on the 100 hue test and the Nagel and Pickford-Nicolson anomaloscopes that colour deviant and/or colour weak subjects can be distinguished from the wholly normal bulk by considering the normality of certain test result distributions as well as by considering the combinations between test results considered abnormal. The stated minor abnormalities of colour vision are frequent and their types are those described by Pickford and by Lakowski (never' colour asthenopia). They are recognised by means of the anomaloscopes and not by means of the 100 hue test.