Category Archives: Professions

Study on How Color Blindness Affects Pilots

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

Unreliable Secondary Color Vision Tests for Pilot Candidates

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.

Joint Aviation Authorities
Joint Aviation Authorities

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:

  1. Nagel Anomaloscope
  2. Holmes-Wright Type A lantern
  3. Spectrolux lantern
  4. 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.

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?

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.

Police Officer – Does Color Blindness Matter?

“Can I become a police officer even when I’m colorblind?” This is a common question among colorblind young men, when dreaming about a career at the police department.

This article will tell you, if color blindness really matters when you want to become a police officer. First we will have a look at some main factors and possible test methods. After that you will find out more about local regulations concerning color vision and some actual job offers seeking police officers. An in the last part of this article I will list your 6 steps you have to walk through to become a police officer despite your color blindness—or at least to make sure you check all your possibilities.

Imagine the following situation: A police officers witnesses a theft and reports it to the police station. “The suspect is about 35 years old, has brown, dark-brown, no black hair. A orange, I mean green shirt; or was it yellow-red. And blue, almost blue, kind of blue trousers. Skin color—oh don’t care about.” I know, it doesn’t have to be like that if you suffer a mild color blindness. But with some types of severe color vision deficiency this statements are coming closer to the truth than not.

Color blindness is not a definite no go for becoming a police officer, but it’s certainly a big handicap. Before we have a closer look at the topic and the differences in some countries and police departments, you might like to read this story of a colorblind police officer and his personal career.

If you are suffering from some kind of color vision deficiency and want to become a police officer, there are several factors to be considered.

  • Type of color blindness. There are different types of color blindness. The strongest form is called achromatopsia, whereas you can only see in shades of gray. This would certainly disqualify you from being a police officer. For the other types like red-green and blue-yellow color blindness it mostly depends on the factor listed next.
  • Severity of color blindness. Is it only a mild form of color blindness or are you a dichromat, who have only two different color receptors compared to three with normal vision? Mild forms of color blindness are often not even recognized by the person concerned. Only by taking some tests, they’ll find out about it. It definitely depends on the severity of your color vision deficiency, to make a judgment about your fitness to be a police officer.
  • Local recruitment regulations. Different countries, states, cities or police departments have sometimes different recruitment regulations. Most often this includes also some restrictions concerning color vision ability. Check your applicable regulations.
  • Recruiting staff. And last but not least, it depends either on the person who is recruiting you or on your new boss. In the end they will decide, if you are the right person for this job or not. Maybe if you just fit in, they will bend the rules to your advantage.

If you apply for the job as a police officer, this will almost ever include any form of color vision test. Most often this is done with an Ishihara plates test, but also Farnsworth tests and City University tests are in use to test your eye sight concerning color blindness.

Often people say, they just cheat on those tests and that will do it. I think, this isn’t the way to go. What, if they find out afterwards, or you annoy your partner because you can’t see the colors you should? And what if they will find out during the test, because cheating isn’t always easily done? I recommend to just be yourself. If it is the right job for you, you will find your way with legal methods.

I would like to point out some regulations and job offers I found. You will see, that there are different wordings used when talking about color vision ability and it’s not always obvious what it really means.

Color Vision Deficiency Regulations for Police Officers

To start with I would like to point out this story of a colorblind police officer applicant written down by a chief of the Berkley police department. It shows very nicely, that it’s not always easy to make a judgment and that there are possibilities even for somebody with a color vision deficiency.

In the United States, the New York State Police writes in their qualifications notes, that color blindness is disqualifying. The Washington State Patrol Trooper formulate it with ability to distinguish colors and be free of color blindness and night blindness. A bit less restrictive is the formulation used for recruiting at the Los Angeles Police Department: Candidates must be able to accurately and quickly name colors. A whole battery of tests has the City of Falls Church requiring that Candidates must pass near vision, color blindness, darkness perception, night vision, and peripheral vision tests. And on the other side we have the very concise formulation NO color blindness of the Portsmouth Police Department.

If you jump over the Atlantic Ocean and have a look at some regulations concerning the recruitment of police officers in the United Kingdom, it looks a bit different. According to policies of the Police Service of Northern Irland, an applicant must have 7 out of 10 correct replies in the City University Colour Vision Test. The detailed eligibility requirements for color vision of England and Wales read as follows:

Monochromats should be rejected. Mild anormalous trichromats are acceptable and should be treated as normals. Severe anomalous trichromats and dichromats are also acceptable but should be instructed in coping strategies.

Whereas color vision should be tested with the Farnsworth D-15 test and applicants should not wear ‘color correcting’ lenses during the color test (eyesight standards for police recruitment). A similar wording is used in the eligibility notes of the British Transport Police.

As the last station, we have a look at Switzerland, the country I’m living in. The regulations I found are the most fuzziest ones. The Kantonspolizei Zürich is looking for people with some Farbwahrnehmungsfähigkeit (ability of color perception) and the Kantonspolizei St.Gallen states that aspirants must have in der Praxis ungestörte Farbwahrnehmungsfähigkeit (undisturbed ability of color perception in practice). This is free to interpretation.

Police Officers Job Offers

Looking at some actual job offers for police officers, you will find some similar or even stronger wordings as in the regulations mentioned above. The City of Manteca expects you to be free from significant color blindness and also the City of Pasadena states explicitly, that you have to be free from color blindness. Compared to this the formulation chosen by the City of Ames sounds a bit less restrictive: Vision cannot be inhibited by color blindness or night blindness.

But anyway, job offers seeking a police officer are most often including one of the wordings above and sound very restrictive. Don’t be intimidated by those formulations. Of course everybody is always looking for the perfect match in a job offer. But if color blindness is your only disadvantage you might find your way through anyway.

Your 6 Steps

Recapitulating the facts listed above about regulations and job offers, you have to conclude that color blindness does really matter when you try to apply for an employment as a police officer. With a severe color blindness there is only a little chance to be employed. On the other side with a mild form of color vision deficiency, you might have some chances. Specially in the UK, where the regulations are the most liberal, you could make your way.

Let’s go back to our initial question, if you can become a police officer when suffering some type of color vision deficiency. As we learned, the answer is neither yes nor no. It’s something in between. And becaus you not just give up but keep trying hard to accomplish what you are aiming for, I list six steps you have to take to become a police officer despite your color blindness.

  1. First of all you have to check the severity of your color vision deficiency. This can be done either superficial with some online color blindness tests or thoroughly at your local eye specialist. If you suffer from a strong form like complete red-blindness, it will get quite tough for you to find a job as police officer. So this first step should help you to plumb your chances of success.
  2. After that you should try to find the eligibility notes of your chosen future employer concerning color vision. There are many different nuances in the regulations and they will give you some idea, what they demand. For example the LAPD is much more liberal than some other police departments.
  3. Before you apply you might ask, if color correcting lenses are applicable. There is a possibility of buying some lenses, which can help you to better distinguish certain colors. They don’t make you see more colors, but help to see some differences you can’t see without them. Some police departments might allow you to wear such color correcting lenses. Don’t hesitate to ask them.
  4. If you’ve taken the first hurdle of the employment process, you almost certainly will have to pass a color vision test. Take the test as good as you can without cheating. This will show them the truth about your color vision abilities and of course will be the basis for their decision making. If your application will be denied, try to find out the reason behind it. Maybe it’s not only your color blindness but also some other aspects. And if it is only because you’re colorblind, try to find out more about it; why they won’t employ you. This will help you to get a better understanding, if your type of color blindness is a barrier or not in your job life as a police officer.
  5. Failed the first time? Don’t be disappointed. You might try different police departments where you can apply as an officer. This will take you back to point #2 of this six steps list. And because regulations can be so different, there is most often a chance at another place to get the job you want. Only if you applied for more than one job you can say, that you did everything to make your dream become true.
  6. And if the first five steps didn’t help you to become a police officer, why not start with an other job in the police department and go on from there. There are not only police officers working at a police department. You might find another job you can start with and make your own way. If you are inside the system, usually some more opportunities will open up for you. So don’t hesitate to build your own personal career.

An to answer the starting question: YES, you can become a police officer even if you are suffering some form of color vision deficiency. BUT the way might not be the easiest one and it definitely won’t become true for some of you who are severely colorblind.

Color Blindness – Reason for a Job Rejection

One reader of Colblindor was so kind to write me his story about a job rejection because of his color blindness. It’s not a severe color vision deficiency he is suffering from and the job is mostly down with computer support, but he was still rejected.

Well, yes I was declined for one job for my red-green blindness. It was a job in the area of car paint development (research and development). I have worked in the past in areas that have something to do with color (formulation an equalizations) and it never represented for me a problem (I have to say that some times I noted that some colors were harder to make equal than others, but nothing more…). The doctor said that I wasn’t able to do my job.

By now I am trying to demonstrate that I’m perfectly able to that that job. Principally because the equalizations process doesn’t base upon the only eye of the human, the coloration process is carried on with the support of scientific instrumentation, like colorimeters and spectrometers, a lot of times more objectives and exacts than the weak human eye…

Note: Do you know what is the worse about been rejected for a job? They don’t even tell you why, they just say you…”a problem with the vision” :(

Were you ever rejected for a job because of your color blindness? It would be great to hear more about it.

Contribution by Israel F.F. Thanks a lot.