Color vision test
Color vision defects are common, especially for males. The most familiar color vision problem involves confusing reds and greens. Some individuals may also have problems with colors in the blue-yellow range. The standard test for assessing color vision defects is the pseudoisochromatic plates test.
The pseudoisochromatic plates test is contained in a book and consists of a variety of color plates. The plates have different patterns such as numbers, letters, figures, or a winding path within a series of dots that vary in hue and brightness from the background. For example, one plate may have a background of orange dots and the figure will be in olive dots. To a person with normal color vision, this is easily distinguished but to someone who is dichromatic (two colors appear to be the same like red and green) no figure will be seen.