A suite of tests diagnose color vision deficiencies (a.k.a. color blindness).
The online version (https://www.biyee.net/color-science/color-vision-test/) started in 2000 and has been used by millions of people all over the world.

They are based on the same principles as Ishihara plates used by optometrists, but use test plates that are randomly and accurately generated at run time. This is different from many other tests using scanned or static images that can be grossly inaccurate.

The prevalence of color vision deficiency is about 5%. Most of them are caused by the missing or defect of one of the three cones in the retina responsible for color vision. If one cone is missing, it is called dichromacy which has three types corresponding to the three cones (protanopia, deuteranopia, tritanopia to L-, M-, S-cone respectively). If one cone is defective, it is called anomalous trichromacy also with three types corresponding to the three cones (protanomaly, deuteranomaly, and tritanomaly). This app is intended to identify these color vision deficiencies.