The following story was sent to me by Dave. He is slightly colorblind and while applying for a job on the way to his new career he had to pass a color blindness test.

Unfortunately the new employer wasn’t really colorblind friendly. Read his story to learn more about the way he had to walk along.

I needed to pass a medical clearance in order to be qualified for training. This was no big deal…except for the Ishihara Plates.

Needless to say, I didn’t pass the Ishihara plates and needed to take subsequent “color deficiency” testing, which I needed to pay for at my own expense. The employer requires all of their employees to pass the Farnsworth D-15 AND the Farnsworth-Munsell D-100 if they have failed the Ishihara plates.

So, I went to my eye doctor and passed the D-15 with relative ease. My doctor thought that the D-100 was extremely overkill and completely unnecessary (partly due to the fact he did not own one). So I needed to spend $659.00 to purchase one myself to bring to my doctor to get tested on.

The D-100 is an amazingly intricate test and cannot be learned. So, I prayed that I would pass. I did very well (at least I thought so) on the test and scored an Error Score of 32. Which easily falls into the range of “Normal Discrimination”. The scoring break-down for the D-100 is as follows. Error Score of 0-16 “Superior Discrimination”. 17-100 “Normal Discrimination”. 100 and above “Poor Discrimination”.

Needless to say I didn’t need the D-100 and the company wouldn’t take returns, so I happily donated it to my eye doctor.

So, thanks for the site and giving me the hope I needed to pass the test!

Thank you very much Dave for sharing your personal story with us. And all the best in your new job and with your new career.

Is My Son Colorblind?

October 24, 2007

@colblindor

Children 5 Comments

When your child starts to learn colors the question of color blindness often arises. Does your child understand the colors correctly? He or she is mixing some colors or can’t name them correctly. Is this color blindness or is it just to early to know?

Many mothers and fathers ask if their son or daughter has a color vision deficiency. Here are some example questions of anxious parents:

My son has a hard time with red and yellow. Could my 3 years old be colorblind?
Is it too early to tell if my 2 1/2 years old son has problems with colors?
When should we test our son for color blindness?

Usually it is all about sons. Because of the inheritance pattern of color blindness, males are by far more often colorblind.

I would like to tackle the question about a possible color vision deficiency of your child with the following three points:

Development of color vision in children.
When to test your child for color blindness.
Why you should check the color vision of your child.

Before I get into the details of the above three topics I would like to say a few words about color blindness itself. In each school class there is on average one colorblind child. Red-green color blindness is the most common form while the terminology is misleading. Every normal colorblind person has a very colorful visual spectrum—just a bit less colorful. This can range from almost the same vision as non-colorblind people to a quite reduced sensation of colors, but still a colorful one.

Only if you have a complete color blindness you would have monochromatic vision. This would allow you to see shades of gray but you couldn’t perceive any real colors at all. This type of color blindness only affects one out of more than 30’000 people and you would recognize it already at a very young age.

1. Development of color vision in children. At the beginning a newborn has to develop its vision. Only after a few weeks a baby can recognize high contrasts in colors like black and white. Color vision evolves steadily and at the age of about six month they have full color vision.

At the age of two a child starts to match colors. They can give you for example a block of the same color you’re holding in your hand. As colors can be matched they still can not grasp the naming of colors yet. This starts at about the age of three years. Only then your boy or girl will name the some main colors correctly.

And it will take another one to three years to name colors accurately. It is said that a child has developed normal color naming between the age of four and six years.

2. When to test your child for color blindness. As we learned in the above section that color vision and color naming evolves slowly the question arises, when is the best moment to test your child for a possible color vision deficiency.

First of all you shouldn’t just check your child for color blindness if there isn’t any evidence for a possible color vision deficiency. It wouldn’t really help you because there is also a possibility that a color blindness test shows a deficiency if there isn’t any. So if you have some evidence, when should you test?

Test for color blindness just before your child will enter kindergarten.

Most of you will ask now, why shouldn’t I test earlier if my son or daughter shows problems with color matching and color naming? I would like to give you a few arguments, why you shouldn’t test earlier.

Before kindergarten-age your child might not have developed complete color naming abilities.
You shouldn’t push to hard on such things like color vision. Give your child time to learn and understand the concept of colors.
Don’t make yourself crazy with a possible and often wrong diagnosis of color blindness of a very young child.
Try to understand your child and don’t try to analyze everything. This way you will understand your child much better and you will be able to help him or her much better.
It won’t really help your child and you if you know to early about its color blindness. Because your child will not really understand it or he/she will already feel like “having a handicap”.

3. Why you should check the color vision of your child. As I said before, don’t just check in anyway but only if there is some evidence. But if you think your boy might be colorblind, let him check or try some of the online color blindness tests.

And why? Because this way you will learn more about his color vision ability AND know his main problem colors (like red and green) AND last but not least you will understand and learn how to support him and can pass this knowledge on to his teachers.

Even if there is one colorblind child per class on average most teachers are not aware of color vision deficiency and most often don’t know how to handle it. They either don’t know what they can do to help a colorblind child or don’t know the colorblind children in their classes.

If you know about the color blindness of your son, you can not only support him but also help others to understand his vision and how they can help him.

Picture taken by Leonardo Sagnotti – some rights reserved.

5 Online Color Blindness Tests

October 7, 2007

@colblindor

Tests 23 Comments

Do you ever wanted to test your color vision? Are you not sure if you might suffer from some type of color vision deficiency? Here are five ways to test online if you are colorblind or not and also to give you a clue about the type of your color blindness.

Color blindness tests are often used check if you fulfill some job requirements. Certain professions like police officer or pilot most often require very good color vision. But also a lot of mothers are curious about the color vision of their children.

The following five checks are quite different but serve the same purpose. So if you take a few of them—or even all five—you will get a quite complete picture of your color vision abilities. Please add your thoughts, ideas and maybe even your test results in the comments section.

1. Ishihara plates color blindness test.

This plates are named after a Japanese professor and by far the best known test for red-green color blindness. They are made out of many colored circles and are showing a number, which can only be seen if you are not colorblind.

The test can tell you if you either are red- or green-blind, but can’t tell you a lot about the severity of your color blindness. Ishihara plates are often used by eye doctors to check for color blindness.

2. Farnsworth Dichotomous Test (D-15).

The Farnsworth D-15 test is also a very well known and belongs to a category of color blindness tests called Color Arrangement Tests. All these tests are based on different colors—in this case 15 of them, sometimes consisting of up to 100 different hues—which have to be arranged in the correct order.

According to the order you choose a tester can find out if you are suffering from a red-, green- or blue-color deficiency.

City University CVD Test

3. City University Dynamic Colour Vision Test.

Professor John L. Barbur from the City University London does a lot of research in the area of color vision and color blindness. He and his team developed a computer color vision test based on the same principle as the Ishihara test.

They are offering the City University Online Color Vision Test also on the web in a very simplified version. The City University color vision test is good to test for any type of color blindness.

Color Blindness Test - Example Screen

Color Blindness Test at biyee.net

4. Color Vision Test at Biyee.net.

This great online test has no long history or well known institute in the background. It is simply a Color Blindness Test based on Confusion Lines of the CIE 1931 Color Space.

But a very good one which is available online.

You have three different tests, one for each type of color vision deficiency: protan, deutan and tritan defects. And the test results tell you a lot more about the type of color blindness you are suffering from.

Color Blindness Test – Color Matching

5. Multiple Choice Color Vision Test.

The French optician Jean Jouannic offers an Online Multiple Choice Color Blindness Test based on 31 images. The images are either hidden signs and letters or a handful of colors which you have to match to a choice of color names.

As colorblind people show great difficulties matching color names to colors, this is another appropriate method to test color vision.

The test has some nice statistics when you have finished and tries to quantify your color blindness in detail.

You should know, that all online color blindness tests are not truly reliable. Because of different display settings, display gamma values and ambient light situations you can’t rely on the results of online color vision deficiency tests. They will show you the direction, but for a reliable result you have to visit an eye specialist.

Colorblind People Feel Handicapped

September 27, 2007

@colblindor

People 13 Comments

I was trying to find out, if color blindness does handicap you in your everyday life or if you get along without this feeling. Thank you very much for participating in this poll which was started ten days ago with the question: Do You Feel Handicapped by Your Color Blindness?

Answer	Votes
Yes, sometimes	35
No, not really	17
Not colorblind	9

We had just over 60 people sharing their feelings about their color blindness with us. Nine of them aren’t colorblind themselves but still voted. This tells me that there are also a lot of people looking for information about color vision deficiency without suffering from it themselves. Thank you.

The other 52 votes can almost be split into two third/one third. Twice as many people feel handicapped as rather not. Of course this are very subjective impressions but that’s exactly what it is meant to be. Only if you are colorblind yourself you can judge about how it feels to carry this deficiency around with you every single day. And no academical study can ever prove it differently.

Looking at the numbers it is a very clear result we got here. To tell you the truth, when I started the poll I thought it would be maybe half/half between felling handicapped and not. But this results teach me that I was wrong.

There is also something else we have to take into account. Not everybody suffers the same severity of color blindness. And I suppose people with a less severe form would more likely vote for not feeling handicapped than people with some severe forms like dichromatism (red-, green- or blue-blind persons).

All together this tells you, that colorblind people definitely feel handicapped in their everyday life. There are so many situations and stories to tell where color blindness is a little or even a big burden.

And even so there is no organization or foundation, no real entry point for people looking for information about color blindness; and even more important, nobody represents the concerns of colorblind people towards the government, schools, employers…

Can Color Blindness Cause Eye Pain?

September 20, 2007

@colblindor

Academic 2 Comments

Usually everybody talks about congenital color blindness—inherited through your parents.

But there are also many people who are suffering from acquired color vision deficiency which isn’t present from birth on and even could disappear again after a certain timespan.

Several days ago my boyfrined told me that his eyes started to hurt form time to time. He never had problems with the eyes. He is a web designer and a programmer though. This pain was increasing from day to day and yesterday the doctor told him that he has some type of Daltonism. He started to loose the real colors during dayperiod. He was told to get physical health and make exercises often.

I want to know is this possible? Can this be a real diagnoses and how can we help it?

It is definitely possible to loose color vision. This can be caused by many different diseases, some of them I’ll list below. Concerning this diagnosis the main question I would ask is:

Can any form of color blindness cause eye pain?

In this case you can compare it with near- or farsightedness. Some people have it, some not. Most people get farsighted when they get older but most important of all, it never causes pain. This is just what and how you can see, but it can never be the cause of pain. It might only be a symptom for some other disease.

This is the same with any type of color vision deficiency. It doesn’t matter if you acquire it or suffer from some congenital form, color blindness never causes any pain. In this case the described color vision problem is caused by something else. The color blindness itself is a side-effect of this and the pain must be caused by something different.

Here is a list of possible causes to loose color vision:

Diabetes, a disease in which you don’t produce or properly use insulin.
Injury. A strong hit on your head could make you loose color vision.
Age.. With age some changes in the eye can cause a blue-weakness.
Chemicals, Drugs and heavy Tobacco smoking.
Glaucoma

This list is not complete and there are many other diseases which can in certain cases cause color blindness.

Comparing the above description of eye pain and the list of diseases which could be a cause of loosing color vision, I would say it could be some form of Glaucoma. This is caused by an increasing pressure of the fluid inside the eyeball. There are many different forms of glaucoma, but some of them can cause eye pain and can develop enough pressure onto the blood vessels in the eye to cause some form of color vision deficiency.

The advice to get physical exercise sounds a bit strange to me but it could help (I’m not an eye specialist). Most important is, that color blindness doesn’t cause eye pain and therefore there must be something else causing the pain and with the side effect of loosing proper color vision.

I would strongly recommend you to contact an eye specialist to find the real reason behind the pain. He should be able to give you a proper diagnosis and hopefully can cure it.

You might also like to visit the Glaucoma Research Foundation, which provides a lot of very useful information and also offers help.

Poll: Do You Feel Handicapped by Your Color Blindness?

September 17, 2007

@colblindor

People 8 Comments

This poll is finished. You can see the results at Colorblind People Feel Handicapped.

As we know, color blindness is very common among men. Approximately every twelfth men is suffering from some type of color vision deficiency, most often some form of red-green color blindness.

And this group of colorblind people—including the colorblind women among us—can be split into two parts: On one side you have the persons who don’t think that their color blindness is an obstacle for them. They don’t really feel handicapped through it and often forget about it in everyday life.

On the other side we have colorblind men and women who feel in some way uncomfortable with their color vision deficiency. Now and then there are situations coming up where their color blindness handicaps them. It’s not all the time but they think more of their deficiency as a burden they have to carry.

To which side are you belonging to?

Please join in the poll and share your answer. You can also find the poll on the sidebar where you also can get a glance at the results of the ongoing poll on a daily base.

The poll will be running for ten days. So I’ll post and comment the results September 27th on Colblindor.

It would also be very interesting to know in which way you feel handicapped or if not, why not? Please add your thoughts in the comments section and share it with other colorblind visitors.

Red-Green Color Blindness doesn’t mean You can’t Distinguish Red from Green

September 14, 2007

@colblindor

Thoughts 14 Comments

Often people think that if you are suffering from red-green color blindness you can not distinguish red from green at all. But they are wrong.

The term red-green color blindness isn’t accurate and doesn’t describe the actual color vision deficiency correctly. If you have a look at the confusion lines of the CIE 1931 color space you will see, that there are many different lines in the color space which connect undistinguishable colors to a colorblind person. Therefore a red-green color vision deficiency makes you colorblind to many more colors than just red and green.

On the other side it depends strongly on the brightness and saturation of colors to make them hard to distinguish if you are colorblind. Colorblind people often develop some sort of color intuition which is based not only on the hue but also on the brightness of the color they see. Something which is hard to imagine if you have normal color vision.

For example some shades of red are close to green, others close to brown and again others are even close to black. The following list shows a few examples of colors which look close to each other and can’t be distinguished easily if you are suffering from red-green color blindness:

yellow — bright-green
orange — grass-green
apple-red — leave-green
dark-green — brown
blue-green — gray — purple
dark blue — violet

As a conclusion you can say that some reds and some greens are very well distinguishable. It depends very much on the brightness and the saturation of each color to make them undistinguishable for a red-green colorblind person.

Study on How Color Blindness Affects Pilots

September 13, 2007

@colblindor

Professions 26 Comments

Besides the unreliability of color vision tests for pilot candidates it is also often discussed, how well your color vision has to be to acquire a pilots license.

Usually you have to have normal color vision—or at least almost perfect color vision—to pass the medical tests on the way to get a pilots license (color vision information for pilots). Any type of color blindness is a no go.

Not everybody agrees with this color vision standards for pilots. While some argue that perfect color vision is required to manipulate all the complex cockpit instruments correctly and see the warn and signal signs for aviation, others say that you don’t need to have perfect color vision to be a good and most important securely flying pilot.

The National Transportation Safety Board (NTSB) wants to find out more about how color blindness affects pilots. They started a major study and researchers are determining whether color identification difficulty develops, worsens or stays the same at high altitudes.

They are working together with the Federal Aviation Administration’s Civil Aerospace Medical Institute (CAMI) and are giving volunteers several color vision tests to identify relations between color blindness and different altitudes. The outcome of this study could provide new sources of information for the requirements on color vision when acquiring a pilots license.

KSBI-TV news on the major study how color blindness affects pilots

Picking Fruits as a Colorblind Man

September 11, 2007

@colblindor

Stories No Comments

We have got an appletree in our garden and today I finally found some time (and motivation) to pick all the ripe apples. Besides handling them with care and sorting them out, the toughest part for me definitely was the picking itself.

My red-green color blindness turned out to be quite a handicap while trying to find all the apples on the tree. The apples are mostly yellow with some of them turning red. I also wanted to pick the rotten ones which show any color between yellow-red and brown.

As the tree has many green leaves and brown branches it was really hard work to spot all yellow, red and brown apples. Not because they were hidden inside the tree but because I couldn’t really spot them by their color.

The picture here pretty much shows you how it looked like. You might say now, that there isn’t a huge difference between the apple and the leaves even for somebody with normal color vision. But for my colorblind eyes, there is no color difference at all. I can only spot the apple by its shape.

Conclusion: I definitely wont become a fruitpicker—at least not in this colorblind life.

Unreliable Secondary Color Vision Tests for Pilot Candidates

August 28, 2007

@colblindor

Professions 16 Comments

If you want to acquire a pilots license, you need to pass medical checkup including a color vision test. If you fail the color blindness test you will get a second chance with a different color vision deficiency check. Unfortunately some researches from the United Kingdom could show, that those secondary color blindness tests are not reliable enough.

The Joint Aviation Authority (JAA) in Europe is the counterpart to the Federal Aviation Administration (FAA) of the United States. The JAA provides the standards of safety in aviation, including the rules on color vision tests for pilot candidates.

For the first color vision screening a set of 24 Ishihara plates are used. If you can identify the first 15 plates correctly without any hesitation you will pass the test. If not, you will get a second chance to find out if your color vision abilities are good enough.

The second test differs between countries. There are four different secondary color blindness tests approved by the JAA and in use:

Nagel Anomaloscope
Holmes-Wright Type A lantern
Spectrolux lantern
Beyne lantern

The anomaloscope is based on matching yellow to a mixture of red and green whereas you can adjust the brightness of yellow and the red-green mixture. The lanterns on the other side consist of several colored lights which have to be identified correctly. They are simulating signal lights used in aviation.

If you pass the second color blindness test you fulfill the color vision requirements for pilot candidates. Therefore one should think that those four tests are leading to the same result. But they are not.

A team around Prof. J. L. Barbur of the Applied Vision Research Center, City University, London, researched those different color vision deficiency tests (Color Vision Tests for Aviation: Comparison of the Anomaloscope and Three Lantern Types).

Secondary Color Blindness Test Results for Deuteranomalous Trichromats — Secondary Color Blindness Test Results
for Deuteranomalous Trichromats

As the results on the right hand side show, it depends on the color blindness test used in your country if you will pass or fail the test. The table shows pass/fail rates on all four secondary color vision tests for people suffering from the most common type of color blindness—deuteranomaly.

The researchers could also show, that all participants with a severe color vision deficiency will fail the tests. So the problem resides only for people with some mild form of color blindness.

Consistency is lacking in color vision testing and an aspiring professional pilot may be accepted without limitation in one country, and rejected outright in another. The different tests also reveal different aspects of color deficiency and the severity of outcome may or may not relate directly to the subject’s ability to discriminate colors.

As a conclusion it can be said that a more reliable and less variable internationally accepted color blindness test has to be found.