The aim of the website www.colourmed.com is primarily practical. It is to give information on the practice of medicine for those with colour vision deficiency. There is a sizeable body of evidence that this deficiency is a problem in medicine:

• Medical practitioners report difficulty seeing the redness of inflammation and fresh blood in body products.
• They have difficulty recognising pallor and the body colour changes of jaundice and cyanosis.
• The colour stains in histological preparations can be a problem as can the colour codes used in charts and instrument displays.

There is the risk of medical error with adverse consequences for patients. Moreover, medical practitioners may be anxious about the risk of error and have diminished confidence in their diagnostic ability.

Colored Pills – a problem for colorblind doctors and patients.

In a survey of colour vision deficient medical practitioners some made remarks such as “You do not necessarily know when you have a problem – others point them out” and “The problem is I do not know what I am missing” and “I feel I am very vulnerable … there are times when patients describe red rashes and I cannot see them and nurses point out the invisible dots.” There are large numbers involved because it has been shown that the prevalence of colour vision deficiency is the same in the medical profession as in the population at large.

The situation in the medical profession is complex without any immediate solution to all the problems it presents. Among these problems are

• the varying degrees of severity of the deficiency,
• the different demands on colour vision made by the different specialties,
• and changing technologies in medicine.

In addition there are at present few with adequate training to give the needed advice. It may well be that optometrists if they are made aware of the medical aspects will be the best group to advise individuals towards their career choice. This will be appreciated by medical students: in a survey of 155 color vision deficient medical students by Burke a common refrain was that they did not get advice and support to help them deal with their problem with colour. Seventy-four per cent of Burke’s sample said that it would be useful in their future career to have a full colour vision assessment so that they knew the type and severity of their defect.

The issues involved are sensitive because the safety and care of patients is involved and also the careers of medical students and qualified doctors. It is not surprising that those responsible for standards in medicine have been reluctant to make definitive statements on this issue. We do not advocate the introduction of a colour vision requirement for entry to medical courses.

We take the view that all medical students who have abnormal colour vision should be aware of their deficiency before entering a medical course, and of its severity, have an appreciation of the kind of problems it may cause in their chosen career, and avoid those careers that may cause unavoidable problems. They will then be readier to seek advice and better equipped to find ways to avoid their problems.

One man in 20 is color-blind in greater or lesser degree and for that reason ineligible for training as an Army Air Corps pilot or observer. Last week the Air Corps’s School of Flight Medicine reported an interesting incident.

In a plane at Fort Sill, Okla. early this summer, an Air Corps observer was able to spot only ten of 40 camouflaged artillery fieldpieces on the ground. An observer of the Field Artillery in a plane spotted all 40 and accurately plotted their positions on his map. The explanation: the artilleryman, selected under less rigorous examination than the Air Corps man, was colorblind. Camouflage, designed to deceive the normal eye, fooled him not a whit.

Last week, at the School of Flight Medicine, clerks combed the files preparing a list of candidates rejected for color blindness. But the Air Corps still wants no color-blind pilots. A pilot must be able to distinguish between colors in Very signals, field lights, etc., where a mistake would be costly.

Found at National Defense: Color-Blind Observers.
Thanks to Vasile from Discromat for sending me the link.

I this article of the Color Blind Essentials series I would like to have a closer look at the every day life of a colorblind person and also at the impacts this vision handicap can have on your career choice.

Color blindness in everyday life

Most people think traffic lights are one of the biggest issue for everyone suffering from a color vision deficiency, but they are wrong. The colors for traffic lights are very well chosen and they are always arranged in a certain order. So this is not a problem at all for most colorblind people even if some states don’t allow you to get a drivers license if you are colorblind.

Original and its color blind simulation.

But there are some real handicaps for people who are suffering from some moderate to strong color vision deficiency:

• A Sunburn can’t really be seen, only if the skin is almost glowing.
• If meat is cooked can’t be told by its color.
• There is no difference between the colors for vacant (green) and occupied (red).
• Flowers and fruits can’t be that easily spotted sometimes.
• And you can’t tell if a fruit or vegetable is ripe or not yet.
• Every electrical device which uses LED lights to indicate something is a permanent source of annoyance.
• Colored maps and graphics can sometimes be very hard to decipher.

By far the most biggest issue is matching colors and specially matching clothes.

If you a have a color vision defect you can’t just choose flowers which fit together nicely, or a painting which fits with the furniture, or a carpet. You also can’t create a web site or an image with nicely matching colors. And you will never be able to easily match your shirt with your tie, your trousers with your shoes, your whole wardrobe.

In this case you need a pair of color enabled eyes which help you out. I often borrow the eyes of my wife and sometimes those of my son. They really help me a lot. ;-)

Choosing your career as a colorblind

A color vision deficiency often gets more attention when it comes to choosing a future career. Specially parents are very concerned about possible restrictions. But also young people ask themselves, if the job of their dreams will stay just a dream because of their vision handicap.

Jobs which require good color vision can be split into two different categories. In the first of them color matching or color recognition is a main component of the job. This for example includes color quality control, art teaching, interior decorating and more.

This group of jobs is easy to decide about for colorblind people as each one knows best himself if he will perform well in such a profession or not. Most colorblind people can also accept this fact more or less easily.

The other category includes jobs which also require good color vision but only in support of the job itself. This group includes the job profiles of pilots, firefighters, police officers and more. These kind of jobs have the following facts in common:

• Bad color vision is a security problem in this job.
• Passing a color blindness test is required to qualify for the job.
• The impact of a color vision deficiency is not well described.
• There is no international standard on color vision requirements.

The points listed above unfortunately make it very complicated. Many colorblind people believe that they still could perform in such a position perfectly and that turning them down just because of their color vision deficiency is not correct. Some people even start thinking about how to cheat on such a test just to get through the exams and get the job of their dreams. But this is not the right way to go.

Here is my six steps plan towards your future career:

(1) Learn. During your time at school learn how you can handle colors. Learn about the severity of your color blindness and learn your special techniques to get around your handicap. This way you are very well prepared when it comes to choosing your future career.

(2) Inform. Get all possible information about the job of your dreams and possible handicaps for color blind people. You can get information from a prospective employer, from special authorities like the FAA for pilot candidates and of course from the internet. It’s important to check your local requirements as they can vary between different countries.

(3) Talk. Try to find some people who are working in this job and talk to them. They will know the best if there are special tasks which might be a problem and you will know from your personal experiences, if you will be able to handle and also most important if you will feel comfortable in such a position. First check your relatives, ask around in your neighborhood, maybe you will find somebody at the college and otherwise I’m sure you will be able to find somebody online who will be happy to help you out. Just check forums where those people could hang around.

(4) Communicate. Don not try to hide your color vision deficiency. Be honest and communicate it if it might be a problem. Of course you only have to do this if color vision could be a possible handicap. But it is important to inform your prospective employer what you learned about the job to be done and how you overcome those handicaps despite your imperfect color vision.

(5) Go for it. Don’t forget to take the last step. Do the required tests to learn more about your color blindness. You might pass without any problem and you might fail. You maybe also like to try different employers as there are in most jobs no national rules concerning color vision deficiency.

(6) Discuss. Did you fail the color blindness test and did they use the Ishihara plates or some similar form? Read the chapter about color blindness tests to learn about other possible tests. This should help you to start a discussion about the used test and if maybe this test was just to restrictive. There are many different tests available and sometimes it would be even much better if your prospective employer would just check possible job restrictions and if you can handle those or not.

And please don’t forget the fact, many people have some form of handicap which is a burden and sometimes becomes a big obstacle. Get used to your color blindness and try to accept that moderate to strong color blind people shouldn’t dream to work for example as a pilot or a professional firefighter. If you can’t accept this, don’t try to cheat on the tests but start a discussion about it!

    

Left: normal red apples — Right: colorblind red apples

We are colorblind. We can’t name colors. But we can handle most situations perfectly even if we don’t know which color it is.

In the next and last article of the Color Blind Essentials series we will learn if there are any possibilities to cure color blindness.

Photos taken by clairity and Muffet.

Color Assessment & Diagnosis Test

Because of the lack of reliable, standardised tests and the absence of information on the specific colour vision needs of professional flight crew, the UK Civil Aviation Authority supported by the US Federal Aviation Administration initiated this study.

A team around Prof Barbur from the Applied Vision Research Center in London was mandated to find the minimum color vision requirements for modern flight crew, and a new color assessment and diagnosis test. This was the last part of the study after The Use of Colour Signals and the Assessment of Colour Vision Requirements in Aviation and a Task Analysis which included two operating case studies: the Airbus A321 and Boeing 757.

Dr Sally Evans, Chief Medical Officer at the CAA, says:

“The current diversity in colour vision testing methods and standards demonstrates the need to adopt more objective assessment techniques internationally. If the assessment methods and limits derived from this study were applied as minimum requirements for professional flight crew, 35 per cent of colour deficient applicants would be eligible for medical certification as a professional pilot. The CAA intends to promote this research internationally with a view to gaining acceptance of the CAD test and its incorporation in world-wide medical standards for pilots.”

This sounds very promising for all colorblind pilot applicants! So let us have a closer look at what this new color blindness test is all about and how they reached this new results.

Color Assessment & Diagnosis Test

The current procedures within JAA for pilot applicants are unsatisfactory for at least two reasons.

1. There is no guarantee that the deutan subjects that pass secondary tests can cope with safety-critical, color-related tasks, since the severity of their color vision loss remains unquantified.
2. Many color deficient subjects that can carry out such tasks safely fail the lantern tests and will not therefore be allowed to fly.

This findings and many detailed studies on color vision deficiency resulted in a new color blindness test, the color assessment & diagnosis test (CAD test). The subject’s task is to report the direction of motion of a colored square on a gray square background with dynamic luminance contrast noise. This new developed color vision test has shown in a broad study to be very accurate in identifying type and severity of one’s color blindness.

The subject’s color vision severity is measured in Standard Normal units (SN units). If your result would show a red-green threshold of 2 SN units this would mean, that you need a twice as strong color signal compared to a average standard CAD observer. This threshold can be quit different for deuteranomalous and protanomalous observers as a limit to pass the PAPI test. Details on this are shown in the conclusions.

PAPI Test

The Precision Approach Path Indicator (PAPI) was indicated as the most important, safety-critical task that relies largely on color vision. On this basis a PAPI simulator test was developed to quantify the severity of a pilots color vision deficiency which is still safe to fly. This simulator can be used in controlled laboratory environments.

PAPI Test Simulator

The simulator reproduces both the photometric and the angular subtense of the real lights under demanding viewing conditions when the lights are viewed against a dark background. Since other color-related tasks such as seeing the color of the parking lights or the discrimination of runway, center-line, red and white lights are less demanding, it is assumed that the pilot will also be able to perform correctly these tasks.

The aim was to identify type and severity of color vision deficiency which cause problems with the PAPI test and correlate those results to the CAD test results. In principle, this approach should make it possible to recommend pass/fail limits based on the observer’s ability to carry out the most safety-critical and demanding PAPI task.

Principal conclusions

The very promising results suggest that subjects with minimum color blindness that does not exceed 6 SN units for deuteranomalous observers and 12 SN units for protanomalous observers perform the PAPI test as well as normal trichromats. If these findings were adopted as pass/fail limits for pilots ~35% of color deficient applicants would be classed as safe to fly.

• When the ambient level of light adaptation is adequate, normal aging does not affect significantly either red-green or yellow-blue thresholds below 60 yrs of age.
• Analysis of PAPI results shows that the use of a modified white light results in significant, overall improvements in PAPI performance.The modified white is achieved simply by adding a color correction filter.
• 43 of the 77 deuteranomalous subjects failed the PAPI test. 29 out of the remaining 34 subjects that passed the PAPI test had CAD thresholds < 6 SN units.
• 20 of the 40 protanomalous subjects failed the PAPI test. 13 out of the remaining 20 subjects that passed the PAPI test had CAD thresholds < 12 SN units.

The study also concluded that the administration of the CAD test eliminates the need to use any other primary or secondary tests. When one includes normal trichromats, ~94% of all applicants will pass the so called fast-CAD screening test and be classified as safe to fly. This process is very efficient since the fast-CAD test is simple to carry out and takes less than 30 seconds to complete.

Official CAA news:
CAA research paves the way for more people with CVD to become pilots
CAA Paper 2009/04:
Minimum Colour Vision Requirements for Professional Flight Crew

Brett wants to become a pilot. But he is suffering from a mild form of color vision deficiency which disqualified him.

He is now looking for any possibility which could show, that in some cases weak colorblind people are not less suitable than people with normal color vision as there are many factors which can have quite an impact on your performance and which you always have to be aware of.

Read his request, you might be able to help him:

I have been diagnosed with mild deuteranomaly and have been disqualified from USAF pilot training. I am currently working to get an exception to policy that would allow me to still go to pilot training, and I know how difficult this will be. But I need help with research for my exception to policy package. Today I came up with a simple but interesting idea and tried researching but was unable to find the information I need.

The idea is that since I have mild deuteranomaly, my M (green) cones are shifted a few nanometers towards the L (red) cones. I also know that many other factors can affect the color perception of people with normal color vision, such as the position of the sun in the sky, weather, hazy, cloudy, etc… So what I’m looking for is a measure of how much the position of the sun would affect the color of an object. I’d bet the bank on the sun shifting light wavelength more than my condition.

I’ve looked into color temperature a bit and found at dusk or dawn sunlight has a color temp of approx. 3200 K and at noon its around 6500 K. My problem is I’ve been unable to relate this change of 3200 K to 6500 K to a change in wavelength (nanometers).

Any information on how much the sun would affect color perception, or how many nanometers a person with mild deuteranomaly would be shifted would be greatly appreciated.

I can be contacted at: bmather9@gmail.com

After reading his thoughts you maybe realized that your situation is quite similar. Hereafter you can read his whole story which might help us all to find a better solution to the problem, that many colorblind people are rejected from a job just because of some color vision tests, which are most of the time to unspecific and much to restrictive.

So I’ll start my story about 3 years ago when I began applying to become an Air Force Pilot through OTS. I was in my senior year at Virginia Tech working on my degree in Aerospace Engineering. After turning in my application to OTS I had to wait a while for the boards to make their decision, so I asked to have my flight physical done so that I would know if I was medically qualified before I even entered the Air Force. With the exception of distant visual acuity everything went well and I was given a waiver for my vision (20/200 uncorrected). I passed the PIP1 color vision test with 13/14 each eye. Unfortunately I ended up not being accepted to OTS and was quite disappointed.

Searching for what’s next, I found the possibility of a 2-year AFROTC program I could do while working on my Masters degree. I looked at school and was accepted to Embry-Riddle Aeronautical University’s Aerospace Engineering Master’s program and the AFROTC program their. During my first year their I was selected for a Pilot slot before even going to field training.

I went on to complete my work at Embry-Riddle and commission 3-MAY-09. I had to sit around all summer waiting to EAD but finally did on 3-SEP-09 and began to long drive to Laughlin AFB to wait for ASBC at the end of October, IFS, and someday UPT. I’ve been at Laughlin for just over a month now and received orders to go to Brooks AFB last Wednesday for MFS (Medical Flight Screening). At MFS they did a a few tests, but the only thing I was a bit worried about was my distant vision waiver. All of my tests went fine except for color vision. I scored 10/14 for the PIP1 for each eye failed a few other tests. They kept me for additional color vision tests and determined that I have hereditary red-green (deuteranomalous) green-weak, color deficiency. This is completely disqualifying for Pilot, Navigator, ABM (not sure about this one), Combat Control, Combat Rescue, Special Tactics Officer, OSI, Test Pilot School as an Engineer, and 99% of Astronaut positions.

This has been quite devastating since all of those jobs I listed have been my dreams and backup plans in case my dreams didn’t work out. Having them all stripped away in one day has motivated me to fight this to the end. I’ve been researching quite a bit to come up with anything I can do. I don’t really know who to contact but I’m planning to start with my commander. I plan to tell my whole story and explain why I believe I am fit for at least one of those jobs.

I’ve gone my entire life (24 years) without knowing I had any form of color deficiency and have accomplished a lot; I just don’t see how it can be so bad that I would be at a disadvantage now. I’ve read about potential advantages that red-green colorblind people have such as better night vision (which I found one paper going against this), being able to see “faster” (I haven’t found any scientific evidence), and most notably being able to see through and detect camouflaged objects more easily (still don’t have a solid source, just mentioned in other sources).

From what I can tell the only way I might be able to get around this is to get my commander or someone above him to write an “exception to policy” that would basically say that they are willing to take a risk on me since I might be able to make up for a deficiency with other aptitudes. Other than that, political figures may be able to use their pull somewhat to get me around this (but I know none personally).

If anyone has any information that may be useful to my cause please contact me at bmather9@gmail.com. Otherwise I’ll be busy looking for other careers (which don’t require perfect color vision) that will be as exciting, dangerous, noble, and challenging (both mentally and physically) as that of an Air Force Pilot.