Which color vision test is considered a pseudoisochromatic test?

Ishihara's test of color is recognized as a pseudoisochromatic test because it is specifically designed to identify color vision deficiencies, particularly red-green color blindness. The test consists of a series of colored plates, each containing a hidden number or shape that can only be seen by individuals with normal color vision. Those with color vision deficiencies will often not be able to distinguish the figures as easily or at all, depending on the nature of their color vision issue.

In this context, the term "pseudoisochromatic" refers to the way these plates are created. They use colors that are nearly similar in hue and saturation, making them difficult to differentiate for individuals with specific color vision impairments. This inherent difficulty for those with color blindness is the key characteristic that classifies Ishihara's test in this category.

Other tests like the Farnsworth D-15, Harvard color test, and City University Color Test have different methodologies and do not function primarily as pseudoisochromatic tests, focusing instead on color arrangement or discrimination rather than hidden figures within similarly colored backgrounds.