The City University of London has a well know Department of Optometry and Visual Science. They invest a lot in research for color vision and color vision deficiency which includes their own color vision clinic.
A well known color blindness test called City University Color Vision Test is available in a print version and often used to identify tritan deficiencies. This test is derived from the well known D15 color arrangement test and is based on different plates, where out of four dots the one which comes closest to a fifth dot has to be selected. If you only have very mild form of color blindness, you will pass this test. But on the other side the City University Test allows to identify the type and approximate severity of color blindness.
Now for all of us, looking for a way to test one’s color vision abilities online, they developed a web based color vision test. The test is a little (very uninteresting) movie, consisting of pictures which look like the one right here. In each picture there is a square, which might be hidden if you are suffering from some type of color blindness.
The movie is twelve Mb long, so you need a fast link to play it. But if you can play it, you will have to chance to find out if you are suffering from some type of color blindness. There are some facts which are really great about this test:
- 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.
There is of course also a downside to this. Through this movie you won’t find out how severe it is and which type it is. You don’t even get a feeling, because you don’t know if you can’t see the square for let’s say ten seconds, what this means. Is it just a mild form of color blindness or not? Only the eye specialist will be able to tell you for sure.
Maybe you already have downloaded the web-based color vision test and watched the movie. If the square disappeared for you for some time, you might like to compare your results to my ones. From other online tests and what my doctor told me once upon a time I know, that I have some form of very severe red-weakness or red-blindness. And my test results are:
- Square disappeared 1. time from 0:16 through to 0:26.
- Square disappeared 2. time form 1:04 through to 1:11.
What are your results? It would be great to have some others to compare with. But always keep in mind, that online color blindness tests can’t tell you the truth because there are to many factors like display settings and illumination which affect the test results. To get a proper screening you have to visit your eye specialist.