The test is not only made to detect red-green color blindness, but also for people suffering from blue-yellow color blindness. This is not often the case. Specially the well known Ishihara Plates tests are only for red- or green-weak respectively -blind persons.
Different severities of color blindness are covered within this test. If the square is not visible to you for only a few seconds, there is a big chance that you are suffering some type of color vision deficiency.
It’s the most simplest color blindness test, covering a big range of deficiencies. You only have to watch and see, if you always can spot the square.
