City University Online Color Vision Test

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.

City University Test
Can You Spot It?

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.

23 responses on “City University Online Color Vision Test

  1. Peter

    I lose it on roughly the intervals:

    0:15 @ 0:20
    1:03 @ 1:07

    So pretty similar to yours, and really I think how long it’s missing depends a little on how far you sit from the monitor :).

    My genotype is predicted to be protonopic or possibly trichromat but with two very close L pigments.

  2. Daniel Flueck Post author

    Peter, thanks for posting your intervals. Looks pretty similar to mine ones. What I really would like to know is, if I’m dichromat or anomalous trichromat?

  3. Leo

    I don’t see the square between

    0:15 and 0.20

    and between

    0:59 to 1:05

    The second seems to be slightly different than your’s. I think I am more on the green blind side.
    I made also the other tests your fantastic website links to. On the ‘confusion lines’ test I am completely helpless with the deuteranopia test and still quite unsure with the pronatopia test. The Farnsworth test, however, seems to be trainable for me as I started as near dichromat and after some repeating ended up as slight andoumalus dichromat. Who knows?

  4. Rob

    I couldn’t see the square between 0:20-0:22 or between 1:00-1:05 – there was a patch around 0:18-0:20 when I thought I was just following the pattern without really seeing it…

    I agree with Leo and yourself about the confusion lines tests, 90% ok on tritanopia but the others are just guesswork (40% correct!)

    I found the real difficulty was that either none of the colours were anything like the example, or that at least 2 and sometimes 3 were exactly the same!

    I also found the Farnsworth quite learnable, maybe it would be different with physical disks but as I work in web design I find colours on a monitor easy to remember by some other individual properties (brightness, pixellation, the way the border reacts with the colour adjacent to it) – if they had subtly changed the disks or even the background, I would not have had a chance!

    Plus, the reference disk on the far left, in my vision was not “the right one”, I kept wanting to move it 2 or 3 spaces in…

  5. Mike Matthews

    I lost the square between the following intervals;

    0:13 to 0:17


    0:59 to 1:05

    I understand that the best person to answer my following question would be my eye specialist, but a little guideline advice from you guys would be great if you wouldn’t mind giving it. I hope to undergo a City University Colour Vision Test as part of an application process for a Police Force.

    The application guideline for the particular Police Force requires 7 out of 10 correct replies in this test. Do you think the above intervals of loss of vision of the coloured square would equate to roughly a 70% score as required by the force.

    Regardless of your answers, I will make an appointment with my specialist, but I’d greatly appreciate your input on this one.

  6. Daniel Flueck Post author

    Mike, you might like to read my article about police officer and color blindness to get some more information on this topic.

    As far as I know the online version of the City University Color Vision Test is not the same as used in the check-ups. Most probably the are using a test, which consists of plates with five dots on them arranged in a cross. You have to find the best match between the circle in the center and the other four.

    Unfortunately your results listed above don’t sound like scoring 70% to me. Try out the Ishihara test which can give you a better clue about the severity of your color blindness.

  7. Mike Matthews

    Daniel, I read the article you linked and found it and other articles to be very encouraging.

    I have tried the Ishihara test, where I found a lot of the plates to be illegible and a handful to be successful.

    Thanks to your links, I went on to try the online version of the Farnsworth 15 test on which I scored the perfect curve.

    I also tried the 3 tests on the site where I scored the following;

    Deuteranopia Test
    18 correct, 1 wrong : 94%

    Protanopia Test
    19 correct, 4 wrong : 82%

    Tritanopia Test
    23 correct, 0 wrong : 100%

    So far, I’ve been unable to find an online version of the plates used in the City University test, but I did manage to find a small image showing samples of the plates and a description of how they operate. It seems to be similar to the Farnsworth test.

    These results and the insight into the CU tests leave me very encouraged for the Police Force test in the near future.

  8. Daniel Flueck Post author

    I followed your kind comments throughout Colblindor. Thank you very much and it is nice to hear that you liked my information.

    You test results of the biyee tests really look encouraging. Nevertheless only a offline test will show you your real color vision ability, because computer displays can tamper your results.

    By the way, I just posted another article about a Colorblind Policeman. This guy took a little other way.

  9. liv

    i’m female with green weak something. the optometrist did the ishihara plates on me and seemed surprised. i lost the square from around 20 seconds to 23/24 seconds only.

  10. will

    I had nearly the same timer intervals as you – 00:07-00:23 and 1:03-1:08. My color vision deficiency seems to be relatively severe. As you and I know, the Ishihara plates are mostly just a bunch of meaningless dots. Great web site!

  11. John Flaherty

    Hi my name is John and I took the City University Colour Vision test and failed to see the shape at certain intervals, these were 20secs to 25secs and 1:06 to 1:09.

    Im intereseted in joining the police in the UK, in your opinion would you consider my colour-blindness servere enough to hinder my application?

    According to the Police application I need to get 7 out of 10 in this test to be elegible. According to the results mentioned above is it possible to score my test in a similar way?

    Thank You for your time.

  12. Jason

    I barely seen the square from 0:15 – 0:20. I seen it but it was kinda faint to me.

    From 1:00 – 1:05, I did not see a square at all.

    Does this mean anything?

  13. John

    I lost the square from 0.11 to 0.15. Then later it was difficult to see around 0.58 – 0.59, it was just barely visible then

  14. xavier

    dude from :09-:13 i coul not see it

    and from 0:57-1:04

    can you answer me?

    i followed you on facebook. you can tell how blind I am there.

  15. Imtiaz Ali

    This is strange! I failed Ishihara miserably but I didn’t miss the square moving!
    I even passed Holmes B Lantern Test in my country and the other forms of tests in this website.

  16. Oliver Wiggins

    I recently failed one of my Army medicals, the Colour Perception standad 2. This was a shock and I’ve been trying to find out what it is and how I can counter it to either cheat the test next time or if I can do CP3 and get to where I want to go then do that.

    On this I don’t lose the square, is this good or bad? I’m a little confused :(