Pseudo-Isochromatic Plates to Measure Colour Discrimination

We have developed 3 series of pseudoisochromatic plates for colour vision testing. The plates are arranged in order of increasing difficulty. In the first (red/green) series, a red Landolt C is shown in front of a green background. This series is used to determine the severity of colour vision deficiency. In the second series, colours are located on the protan confusion line, whereas in the third series, on the deutan confusion line. The plates were printed by a calibrated colour printer, then bound in a book. The plates were used to test 320 persons with colour vision deficiency and 20 ones with normal colour vision. Our results showed a 96.25% efficiency in separating colour anomals and colour normals as verified by an anomaloscope. The test book gives prompt results and it is fun to use. A test takes about 5 minutes so it is suitable for mass tests and moreover, it may also be used to test the colour vision of children.