Online Multiple Choice Color Blindness Test

Color Blindness Test - Grid Image
Color Blindness Test – Grid Image

The French optician Jean Jouannic offers an online color blindness test based on 31 images. If you take your time and answer all the multiple choices, you will get rewarded with a nice reporting and probability indicators for the different types of color vision deficiency.

The images are based on two different color judgment systems. The first one consists of images showing a grid with a base color. Letters or signs in second color are integrated into those images. The test is easy, either you can see something or you can not. There is also always a second option offered, but these are just to find out if you’re trying to cheat or not.

You can see one of those grid images on the left side. Unfortunately I can’t tell you the solution for this one, because I can’t see anything but the grid.

Color Blindness Test - Color Match
Color Blindness Test – Color Match

The second system is based on color matching. An image shows different colored squares and the multiple choice offers a huge variety of different possible answers to choose from.

If you have normal color vision, it shouldn’t be a problem to find the right solution. But with a more or less severe type of color blindness you will have quite some difficulties to match the offered color names to the shown image. If you don’t know what to choose there is always an option to say, that you can’t find a good proposal.

Because it is often not easy to make your choice, you should find your answer with a process of elimination. Choose the one which sounds most probably. If you are colorblind, you are aware of the problem that you often can’t name colors correctly. With this elimination process it is definitely easier to find a matching solution.

Enough of information. Here is the direct link to the just described multiple choice color blindness test.

My test results:
I am either suffering a very strong form of red-weakness (protanomaly) or am completely red-blind (protanopia). Let’s have a look what my test results tell me:

  • Correct answers: 21 (out of 31)
  • General indicator of color blindness: 29%
  • General indicator for color recognition: 71%

Only an indicator of 29% to be colorblind? In a first moment this looks strange to me, because I’m definitely colorblind—and not only just a mild form. I think the color matching images are the answer for this low percentage. Because of my color vision deficiency I can’t name any of the shown colors. But using the elimination process I still often found the right answer.

The next list shows all the indicators split up into the different types of color blindness.

  • Deuteranopia indicator: 3%
  • Deuteranomaly indicator: 29%
  • Protanopia indicator: 39%
  • Protanomaly indicator: 0%
  • Tritanopia indicator: 0%
  • Tritanomaly indicator: 0%

Ok, that looks good to me. A 39% percent chance to be red-blind is still a bit low, but at least it is ranking highest. A little strange is the fact, that there is a bigger chance to have some form of deuteranopia than to be red-weak.

What I like about this color blindness test:
It is available online, free to use, you can easily fill out the multiple choice forms and best of all, it shows you your results in a second and offers a whole range of indicators.

And what I don’t like so much:
The color matching images are too complicated to find your solution and don’t work as they should. I’m not so sure about the accuracy of the results, and apart from the test page everything else is just available in French.

But anyway, this is another great opportunity to find out more about your color vision. Maybe you like to try some other color blindness tests and compare the results. Or if you like, just share your indicators with us in the comments section.

Monochromacy – Complete Color Blindness

A lot of people think, if you suffer from color blindness you can not see any colors at all apart from black, white, and shades of gray. But they are wrong.

This form of complete color blindness is a very rare subtype of color vision deficiency among much more common ones like the the well known red-green color blindness. You might say, in this case the wording color blindness isn’t chosen appropriate—and you’re right.

Colourful Bouquet
Colorful Bouquet
Grayshade Bouquet
Grayshade Bouquet

Color Blindness begins when you don’t have normal human vision which might be only a very light change of color perception. And it ends with complete color blindness combined under the umbrella term monochromacy.

If you are suffering under monochromacy, you perceive everything just in shades of gray. This makes it really hard to accomplish many everyday tasks, because colors are such a central part of our life. For example, people suffering form monochromacy might mix up the following colors:

  • green and blue
  • red and black
  • yellow and white

Monochromacy—also referred to as monochromatism—can be observed in different forms and even worse, many different names are in use:

  • rod monochromacy: typical or complete achromatopsia, total color blindness, day blindness
  • blue-cone monochromacy: S-cone monochromacy, incomplete achromatopsia
  • cone monochromacy: complete achromatopsia with normal visual acuity
  • cerebral achromatopsia: atypical achromatopsia

Before we dig a little deeper into the different forms of complete color blindness you should know the basics of vision and specially color vision.

The human eye has two different receptors inside the eye to perceive light. They are called photoreceptor cells. The rods are very sensitive on brightness and used for night vision. On the other side we have three different types of cones (trichromacy) which are responsible for colored day vision. The three different forms of cones have different peaks on color perception: red, green and blue. And the mixture of those three base colors makes us perceive such a huge variety of colors—or at least almost all of us. Compared to cones, rods play no role in color vision.

Rod Monochromacy

In this case your vision relies solely on the rods and the cones are usually not working at all. Some cases also report that the cones are absent, have some irregular distribution or that they show abnormal shapes. Occurrences are estimated to be between 1 : 30,000 and 1 : 50,000. But even if this numbers look very small, rod monochromacy is still by far the most common type of complete color blindness.

Rod monochromatism is often referred to as achromatopsia and is based on autosomal recessive inheritance. In other words, you need two defective chromosomes and it is equally distributed among men and women. Achromatopsia is characterized by the following symptoms:

  • complete inability to differentiate colors,
  • severe light sensitivity (photophobia),
  • long-sightedness,
  • involuntary eye movements (nystagmus),
  • and central depressed vision (scotoma).

Also rod monochromats are completely colorblind, they often learn to associate certain colors with objects and to differentiate some colors by their brightness.

Blue-Cone Monochromacy

This rare form of monochromatism is caused by loss or rearrangement of the genes encoding L- and M-cones. Because of that only blue color receptors (S-cones) and rods are transmitting color and/or brightness information. If you suffer S-cone monochromacy your are usually completely colorblind. But in twilight situations—where rods and S-cones are working—color perception can be compared with dichromatic vision.

There are reports about very different forms of blue-cone monochromacy and it is sometimes not easy to differentiate it from rod monochromacy. No exact number of incidences is available. Scientists estimate the frequency at 1 : 100,000—for men. Because red and green cones are encoded on the sex chromosome, inheritance patterns are similar to red-green color blindness. Occurrences in women are unknown.

Cone Monochromacy

Also known as complete achromatopsia, this form is very rare. Only a few cases have been reported and none of them is fully accepted. It is assumed that they are either have working L- or M-cones and inactive or absent S-cones. Compared to blue-cone or rod monochromacy, cone monochromacy doesn’t have reduced visual acuity or any special light sensitivity.

Cerebral Achromatopsia

In this case optical examinations show normally functioning cones and rods. It is not understood in detail yet, but it is thought that the color receptors are working properly only the information is not reaching the brain or is not processed. Only a few cases have been investigated. Cerebral achromatopsia is unlike the other types of monochromacy not inherited but and acquired color vision defect. It may be caused by trauma or illness.

The academical background and many references on all types of monochromacy can be found in Opsin genes, cone photopigments, color vision, and color blindness by Sharpe et al. An internet information portal on achromatopsia is provided by the The Achromatopsia Network.

Colorblind Person Taking a Visual Acuity Test

Visual Acuity Test
Visual Acuity Test

I need a new pair of glasses and therefor I went to visit the optometrist to test my eyesight. Just before I shook hands with the optometrist I told my wife, that they are always using those tests with a red and a green half, differing in acuity and my color blindness doesn’t let me name them 100% accurate.

Usually the optometrist asks, if the acuity of red or the green half is better and I answer with left or right just because I’m not sure if I pick the right color name. This time it was even better. After a few tests…

Optometrist: You’ll see a red and a green part.
Me: I’m colorblind.
Optometrist: Oh, doesn’t matter. Just tell me which side is better for your eyes.
Me: I can’t really see the red one.
Optometrist: Doesn’t matter. Just tell me.
Me: Green on the right.
Optometrist: Ok. — And now?
Me: The red has no contrast for me. I can’t really see it.
Optometrist: We will see. Which is better for you?
Me: Green again.
Optometrist: And now?
Me: Green. I can’t see the red. And green doesn’t look sharp at all.
Optometrist: Hmm. — What about this?
Me: Green. But very bad.
Optometrist: Ok. We will switch to another test.

She changed the test to another one which was no problem for me. But after a short while she switched back again to the red and green halves.

Optometrist: Can you see this?
Me: Not really.
Optometrist: Which is better?
Me: Green again. But I can’t see the red.
Optometrist: Ok. — And this?
Me: Green, but very blurry. There is no contrast on the red side.
Optometrist: Well, doesn’t really matter. We go on from here.

Finally. – Finally she understood that I can’t see any contrast on the red side because of my color blindness. It was just impossible for me to compare those two parts.

Only after the test I really realized, how crazy this must have sound to the optometrist. Maybe she encountered the first time someone like me with a strong red-blindness. How strange to hear that someone can’t see although he can see.

But I ask myself, why do they still have those tests in use. Shouldn’t they have learned in the last years? I suppose those tests easily could be switched to another color which is much better visible for us red-blind guys. — Dear optometrists, change your test setup taking also color blindness into account.

Can I bee Slightly Colorblind?

If you are colorblind it is not just about being colorblind or not. There are many different types and characteristics of color vision deficiency which you can suffer from. Color blindness is an umbrella term for all those different forms—and not even a good one.

I’m 13 years old and have been told I am red-green colour blind but only slightly. I have done research and taken MANY colour blind tests. But I’m still confused because how can I be slightly colour blind? Either I am or I am not. I have failed most of the tests I have taken and my optician has told me I am slightly colour blind towards red-green (the most common) but want to know how I am only slightly colour blind and what the scientific word for being slightly red-green colour blind.

First of all, you shouldn’t rely on the color blindness tests available online. These tests are just used to give you a feeling what kind of color blindness you are suffering from and how severe it is. But because every computer display can have different color adjustments they are not 100% reliable.

This young reader says, that either you are colorblind or you are not. This is true and false. If you go to your eye specialist and take a color blindness test, he will tell you if you have normal color vision or not. So yes, either you are colorblind or not.

But he can also tell you, what type of color blindness you are suffering from and the approximate severity of it. There is a whole terminology of color vision deficiency which I don’t wont to list here on the whole. Just the most important facts.

  • Types of color blindness:
    • Red-green colorblind: This is the most common form and according to its name, causes the biggest problems with red and green. There are two different subtypes: Red-blind (or -weak) and green-blind (or -weak).
    • Blue-yellow colorblind: This type of color vision deficiency is not so often seen and actually the colors blue and green (not yellow) are the problem area.
    • Completely colorblind: A very uncommon type which makes you see only in shades of gray. Unfortunately a lot of people think that every colorblind person can only see in shades of gray.
  • Severity of color blindness:
    • Anomalous trichromat: You have still three different types of color receptors as someone with normal color vision. But one of them is slightly shifted in its peak of sensitivity and therefore you can’t see the same broad color spectrum as others.
    • Dichromat: Here only two of three color receptors (cones) are working. You have to mix your perceived color just with two signals compared to three with normal color vision. The color spectrum is strongly reduced.
    • Monochromat: Either no color receptors are working (rod-monochromacy) or just one of them (blue-cone monochromcy). Anyway you will have either just grayscale vision or a very very restricted color vision.

This means, that is possible to suffer from any possible severity of color blindness. This because the three different color receptors have a highest peak of sensitivity. With an anomalous trichromacy, one of those peaks is shifted towards another one; usually the red peak towards the green or vice versa.

Because of that shift and the resulting peaks which are closer to each other, less information is available to mix up the final color in your brain. And this makes you either slightly colorblind (peaks still far apart) or more severely colorblind (peaks coming closer).

The academic term for a slight red-green color blindness is either protanomly (red-weakness) or deuteranomaly (green-weakness). Both types are a subtype of red-green color blindness and a form of anomalous trichromacy.

19th Symposium of the International Colour Vision Society

The International Colour Vision Society (ICVS) is an international group of physiologists, psychologists, physicists, geneticists, optometrists, ophthalmologists and others who have a research interest in the many aspects of colour vision and colour vision deficiencies.

ICVS Symposium

This group will hold its 19th Symposium of the International Colour Vision Society from July 27 to 31 in Belém, Brazil.

Here is an introductory excerpt of the Program Book on this years symposium.

A glance at the program reveals that the traditional interests of our Society are well represented this year, including contributions by physiologists, psychologists, physicists, geneticists, optometrists, ophthalmologists, and other related professionals who have a research interest in the many aspects of colour vision and colour vision deficiencies. One special session is dedicated to the Nagel Centennial, the anniversary of the introduction of the W.A. Nagel Anomaloscope in 1907.

The program includes in impressive list of speeches with many topics directly related to color blindness. I’ve chosen some of them in the list below to give you an impression of actual research topics.

  • Welcome to the wonderful world of color: Gene therapy treatment for colorblindness.
  • The effects of colored lenses on the number of discernible colors perceived by dichromats in natural scenes.
  • Surface color perception of color defective observers under dim illuminations.
  • Performance of the Lanthony New Color Test by young children.
  • Mass screening for color-vision deficiencies in Norwegian children.
  • Color deficiency correction – methodology and experiment report.
  • The contribution to Rayleigh matches of the third red-green photopigment of color-defect carriers.

As described above it is also the centennial of the Nagel anomaloscope, which was introduced in 1907. The Nagel anomaloscope was introduced to measure severity and type of red-green color blindness. It is since then the reference on color blindness tests and of course evolved along the way to cover different types of color blindness.

Maybe we will have the chance to get a grasp of some of the speeches and catch a fresh breeze of academical research on color vision deficiency. Stay tuned.

Colorblind Policeman

When reading through Police Officer – Does Color Blindness Matter?, you could think that it is impossible to be a policeman when you are suffering from a color vision deficiency. But I was contacted by K., who told me a different story.

My life long dream has always been to work in law enforcement and about a year ago my life long dream was shot down when I found out that I was colorblind and couldn’t pass a color test. After doing some research on the net I found and gave them a call. At first I spoke with one of their technicians who was able to give me a lot who was very helpful, I started to get very excited.

Could it really be possible to correct his color vision in a way to pass the required color blindness test? After a 20min phone call with the eye specialist he got really excited, because it looked like that there is a chance to get his dream job police officer.

About 2 months later I traveled to Baltimore. They got me the prefect lens for me to pass the color test. I had never worn contact lenses before, as my regular vision is perfect. Several weeks later I retook the color test, passed and was on my way in to law enforcement. My dream come true!

This story really sounds like a dream. But is it allowed to wear corrective contacts for a color vision test?

Before I went in for the test I put the contact lenses in my eyes. “Didn’t ask, Didn’t tell,” and I dont recall every seeing anything that said I couldn’t wear glasses or contacts for the test.

K. is now an unofficial colorblind police officer. I asked him a few more question which I would like to recapitulate in the following interesting points:

  • He can distinguish colors, but couldn’t pass the Ishihara test,
  • he is not wearing the color corrective contacts on his daily job,
  • and he doesn’t feel like his color blindness affects his job in any way.

Should law enforcement recruitment centers reconsider their viewpoint on colorblind police officers? Should everybody try to cheat on color blindness tests in a recruitment process? Or should you be upright and accept, that color blindness is most often a killer criterion to be a policeman?

Day of Links Two

Today I would like to share with you two links to other blog posts which are very much related to color blindness.

Gerald posted a picture on his Photoblog about Red Roofs and Colour Blindness and writes about his problems on color perception. Unfortunately with my red-blindness I can’t help him at all. It looks red, or brown, or anything in between.

The second link points you to a very interesting article: iPhone Available: Except To Color Blind Users written by Glenn. There was such huge a media coverage and I suppose many million people visiting apple in the last days. And apple offered a nice tool to check the availability of their iPhone. The only problem, it’s not made for somebody with red-green color vision deficiency. It is almost unbelievable that these days such big companies break the basic rules of accessibility.

Pretending Color Blindness – How to Uncover It

Usually people cheating on color blindness tests want to pretend, that they have normal color vision. This should give them the opportunity to get a job of their dream like police officer.

In this case it is just the other way around: Pretending to be colorblind to get the right job.

I am a doctor in railway and I have to do medical examination of the candidates for railway services. How can I determine whether a candidate having normal color vision is feigning/malingering of being color deficient.

Beside the question on how to uncover someone who tries to pretend color blindness, don’t you also ask yourself why somebody would do this? I had the same question. But first I will try to give an answer on the uncovering and afterwards I will tell you the reason for malingering of suffering from a color vision deficiency.

Uncover pretended color blindness

There are different possibilities how you can check if somebody is really colorblind or does only pretend it. They all are based on the same source: A non-colorblind can’t possibly know how a colorblind sees the world.

Usually you hear about red-green or blue-yellow color blindness and you could think, that’s easy to imitate. But it isn’t at all. This colors are just the main problem colors. For example I am red-blind and I have problems in distinguishing

  • dark-red from brown or very dark-green
  • orange from a grass-green
  • yellow from a very bright-green
  • but also blue-green from gray from some purple
  • any purples, violets, dark-blues
  • and when is something still very dark-blue and when is it black?

You can see from this list, it is not just red and green (red-blindness is a subtype of red-green color vision deficiency) but also many other colors. And by the way, I easily can distinguish some shades of green from some shades of red. And because of this, it is impossible to really simulate defective color vision.

Color blindness tests

Usually you will use some kind of color blindness to detect color vision deficiency. The most precise tool would be the anomaloscope to check for red-green color blindness. With this tool it is almost impossible to lie. You have to fit a combination of red and green to the brightness of yellow. Answers will always lie on a straight line. So if the match is just anywhere, the test person doesn’t tell the truth.

Using some kind of arrangement test with colored discs which have to be arranged in the correct order, makes it also almost impossible to cheat. The produced arrangement will follow certain patterns. Somebody with normal color vision can’t possibly find this patterns just by arranging them in any order.

Ishihara Plate 23
Ishihara Plate 23

The most common case would be, that you are using some type of pseudoisochromatic plates like the Ishihara color blindness test. They are based on numbers or signs made of many colored dots. And these numbers/signs are hidden to people with certain types of color blindness.

Now what can you do, if you are using pseudoisochromatic plates to uncover pretended color vision deficiency? Here are a few ideas, which you could try out:

  • Show the plates in a different order. Some may have learned just the correct order and know, what they have to see and what not. If you rearrange them, you can find out more about their real color vision.
  • Use the mixed plates. There are plates which include a number not visible to green-blind persons and a second number not visible to red-blind persons. If somebody wants to cheat on this, they really have to know what they can see and what not.
  • Include plates visible only to colorblind persons. Certain shades of color are only really distinguishable if you are colorblind. So if you add some of those plates it will be hard for someone pretending to be colorblind.
  • Don’t use the Ishihara plates. The Ishihara color blindness test plates either containing 24 or 26 pictures are very well known. A candidate could learn them in advance. If you use some other pseudoisochromatic test they will struggle.
  • Mix in some of your own plates. Maybe you have the possibility to make some of your own plates with a program like Photoshop. For instance you could make some with no hidden signs and tell the person under test, that these plates have a sign which can only be seen if you are colorblind. How will they react? A person which is really colorblind, will tell your right away that he can’t see anything.

Other strategies

As I mentioned above, a non-colorblind will never know how it is to be colorblind and which colors can be distinguished and which not. Here are a few more ideas apart from the color blindness test above, which could help you.

  • Make a vision test including red letters among black ones. Ask the person under test to read the red letters. A colorblind person usually can’t easily spot red letters mixed in into black.
  • Let the person name colors. Somebody with color blindness will have problems in the whole range and mix up very typical colors. Someone with normal color vision will have problems to fake a bad color perception.
  • Ask them about everyday problems caused by their color blindness. Problems are for example skin color (has somebody a sun burn or is he sick?), cooking meat (when is it readily cooked?), LED lights (is it green, red, orange or yellow?), color charts and more.
  • Does the person have problems with traffic lights? I mean they are red and green, aren’t they. Usually this doesn’t cause real problems to somebody with a color vision deficiency. But does somebody who just pretends to be colorblind know about this?

You might try these strategies first with a few test persons—colorblind and not colorblind. This will make sure, that you have chosen the correct problem colors and situations.

Why should someone simulate color blindness?

When I received this reader question I of course asked myself, why somebody should pretend to be colorblind? What can you profit from this?

The candidates for employment in Indian railways are selected in seven different categories.These are A1,A2,A3,B1,B2,C1,C2. Employees of Category A1 to B1 are safety category staff who are required to have normal color vision while those of Category B2 to C2 don’t need to have normal color vision.

Many posts like that of booking clerk, parcel clerk, train ticket examiner etc. come in Category B2 and these are quite lucrative posts every new candidate wants to get, since they can generate extra income by corrupt practices.

Those candidates who are sent for medical examination in category A1-B1 often malinger as if they are color deficient so that they may be disqualified for the posts in A1-B1 and can get fitness for category B2.

Very interesting. Thank you very much for asking this question and sharing this insights with us. If you have your own question concerning color blindness, don’t hesitate to ask me.

Love the Colorblind

I Heart Color
I ♥ Color

The Fuck the Colorblind t-shirt seems to be very popular. A lot of people are looking for it and I received quite some comments on it. Some people like it, others not.

Here is the counterpart: I ♥ Color. Well, I know. It’s not really saying anything about colorblind people. But it is also made out of a pseudoisochromatic picture, also known as Ishihara plates. This texts or numbers usually are hidden if you suffer some type of color blindness.

Can you see it?

The shirt is available at Threadless T-Shirts. And there are some nice pictures of happy people wearing it.

Now it’s up. You can decide between Love the Colorblind and Fuck the Colorblind. Which message do you prefer to put on your chest?