Subjects with 'normal' color vision can be classified as follows:
Superior Discrimination
About 16% of the population (exclusive of color defectives) has been found to make 0 to 4 transpositions on first test, or total error score of zero to 16. This is the range of superior competence for color discrimination.
Average Discrimination
About 68% of the population (exclusive of color defectives) make a total error score between 20 and 100 on first tests. This is the range of normal competence for color discrimination.
Low Discrimination
About 16% of the population (exclusive of color defectives) has been found to make total error scores of more than 100. The first retest may show improvement, but further retests do not materially affect the score. Repeated retests reveal no region of large maximum or minimum sensitivity as is found in color defective patterns.
An example of a low discrimination pattern is given in the database of examples (Example.hdb) which accompanies this program.
These figures form the basis of the Classification given by the computer program.
Error scores by normals often exceed that of many color defectives, yet those individuals do not exhibit color blind indications on this test, on anomaloscopes, or on pseudo-isochromatic tests. Such scores point up the fact that the FM Hue Test is a test of color aptitude or ability to make color discriminations. General color discrimination is independent of color defectiveness. Therefore, it is possible for some normals to have poorer color discrimination that some color defectives. Color normals may have good or poor color discrimination; color defectives may have good or poor color discrimination.