The Eyedox genetic test for color blindness doesn’t need any pictures or complicated apparatus, but just a few cells from the inner cheek from where your DNA can be extracted from. This makes the test also available for young toddlers and the results can’t be influenced by misunderstanding, light conditions or any other external factors.

Many colorblind people all around the world are looking forward to get such a scientific, precise and fool-prove possibility to test their color blindness. As there are many different tests around these days, and even some online possibilities to test your color vision, you are never really 100% sure if the results tell you the truth. With a genetic test at hand a new reliable option is available. On option which can make you feel more sure to know your real grade of color vision.

Eyedox Color Blindness Diagnosis

If you take an Eyedox color vision deficiency test, not only your cvd type will be diagnosed but also the severity of it. In detail this means:

• CVD Type: The test is diagnosing anomalous trichromacy including the different subtypes deuteranomaly (green-weak) and protanomaly (red-weak) and also dichromacy with the subtypes deuteranopia (green-blind) and protanopia (red-blind). This means any type of red-green color blindness is diagnosed in detail.
   
• Severity: The severity of your color vision deficiency is shown on a scale from 1 to 100 and it is also assigned to one of the degrees very mild, mild, medium, strong or very strong.

Personally I think the strength of the Eyedox test will be the differentiation between a dichromacy and an anomalous trichromacy and a detailed severity analysis of your color blindness. On the other side we have the weakness of the test, that tritanomaly and tritanopia (blue-yellow color blindness) can not be tested with it.

Genetic Treatment of Color Blindness

Many people are not only looking for an accurate cvd test but also a possibility to treat their deficiency and get rid of it. Especially all the colorblind pilot, police officer, and firefighter aspirants, who are rejected because of their visual handicap. Genevolve did not only invest into a genetic color vision test, but is also looking into the development of a therapy to treat color blindness. Hereafter you can find a possible timeline for this next huge step forward in scientific research of color vision:

1. In the year 2009 some squirrel monkeys were cured of their color blindness by genetic therapy.
2. In the same year Genevolve was founded, a “life sciences company which researches, designs and commercializes non-invasive molecular diagnostic assays and treatments for clinical applications for the color vision industry”.
3. In 2010 a Survey on Gene Therapy for Red-Green Color Blindness was done.
4. In 2011 Genevolve announces Eyedox, a genetic color blindness test which is based on a non-invasive molecular diagnostics.
5. Also in 2011 the US Federal Drug Administration (FDA) requires further animal tests which will require maybe another one to two years of testing.
6. If everything runs smoothly, after that for the first time a handful of selected red-green colorblind people will get a genetic treatment (those are already preselected and nobody can apply for this first test group!)
7. If they achieve success with the first group, more test subjects will be needed to broaden the treatment and get more detailed test results. If you like to, you can enroll for this second phase. But be aware, this can take another one to three years until those test will get started.

Some Thoughts

I really think it is great work what they are all doing. We will all learn a lot more about our color vision and maybe in the future, some people can even cure their color vision deficiency. But I also think we should ask ourselves, if we really need a genetic treatment just to see some more colors in our life or to get a possibility for the job of our dreams. Do we have to alter our genes for that? What else happens to a human body if we do it? How far shall and can we go when it comes to the innermost of every thing alive?

Anyway. Genevolve, we are all eager to learn more about your next steps and your success stories of treating color blindness and we are looking forward to learn more about your genetic color blindness test as soon as it is available.

During the last year his son T.J. Waggoner started an online color vision testing possibilty together with his father. This test of course is based on the research done by Dr. Waggoner and consists of a set of pseudoisochromatic test plates. I had the possibilty to take this online color vision deficiency test and would like to give you some insights into the test and as well I would like to share my thougths about it with you.

I already reported about this new online test possibilty at Online Pseudoisochromatic Plates Color Vision Test. Since then they made some major improvements on the test and it can give you some more detailed results on your actual color vision deficiency type and severity.

So first about the test itself: It consists of four different parts, starting with a general color blindness test the second to fourth part are related to the three different main types of color vision deficiency: Protan defects, deutan defects and tritan defects. Each part has a set of pseudoisochromatic plates (the circle pictures with the dots) with some “hidden” numbers. Now what you have to do is:

1. Have a look at the plate (you’ll get only 2 seconds to do that).
2. Choose on the answer page, which number you have seen. Or choose nothing, if you haven’t seen anything at all.
3. Press Next and you’ll be shown the next plate.

At the end of the test you’ll get a result sheet which shows your correct and wrong answers for each section. On the right side you can see my personal test result.

As you can see, the four different parts are shown each seperately. I haven’t seen a lot — nothting new to me — but what I like is the extra feedback that according to this test result I’m a Severe Protan (Red-Blind), which correlates with all my other results perfectly.

Are this test results reliable?

At this point it is getting a bit more complicated. Can you believe in this result? Does it tell you the truth? Or is it just another unreliable online color vision test?

Unfortunately nobody can tell you the truth at this point. It is still very well known, that if you want to get to most precise result, you have to check your vision specialist and take an anomoloscope color vision test — the golden standard when it comes to color blindness testing.

But this new possibilty could get closer and closer to a very good result. Of course you shouldn’t cheat, but I can tell you it’s not easy (if you don’t have somebody besided you which tells your the right answer) and you would only cheat yourself anyway.

There are no academic results around yet for this new test. This always takes quite a long time. But some studies have started, it looks like if the FAA has also a look into it and some other studies try to find out if this could be a new possibilty for color vision deficiency testing.

If you would like to try out this new online color blindness test at www.Testing Color Vision.com just use my discount code «colblindor» and you’ll get 20% off!

I now that displays are differently calibrated and therefore you can get different test result while using different computers or electronic devices. But are those differences not getting smaller and smaller? And are vision specialists not as well a little bit error-prone? Which is better? — What do you think…

Pseudoisochromatic plates are the most well known type of color blindness test. The dotted pictures are often referred to as Ishihara plates, becuase Dr. Ishihara developed the first set of such plates which were used all around the world to test for color vision deficiency.

There are many different versions and varieties of pseudoisochromatic plates tests available. Usually they are used as printed tests because it is crucial to get the colors right. Slight changes of the used colors can alter the result and would make a test unreliable. This is also the reason why such tests are usually not used online as display setting, different monitors and surrounding light change the perception of color and therefore the results can’t be trusted on.

Dr. Terrace L. Waggoner, a well known optometrist when it comes to color blindness, developed one of the best known Ishihara plates tests. He made some special research when it comes to pediactric color vision tests and produced Color Vision Testing Made Easy.

His son T.J. Waggoner took now a new way and made some of the pseudoisochromatic plates available as online test. There are two different test sets: One consisting of numbers and a pediactric test consisting of signs. Everybody can take those tests for a small fee. You will find them at Testing Color Vision and don’t forget to use the Colblindor discount code «colblindor» to get 20% off.

The Pros
It’s nice to have a very good Ishihara plates test available online. Of course, you can find many others but usually those are put together as a set of scanned pictures which results in much lower quality and reliability.

I took the test twice, tried to cheat, but couldn’t spot any of the numbers. The quality of the images is really good.

The Cons
There is still no study which could tell us more about the validity and reliability of online color vision tests with uncalibrated computer monitors. I heard they are working on it and I’m looking forward to it. But already now I’m quite sure that an online color blindness test of high quality can be as good as a visit to an eye specialist.

The second thing which I don’t like that much is the result of the test. It just says if you are color blind or not but doesn’t tell anything about the severity. This is something people really are looking for and I would strongly suggest to include this in a future release.

Visit the online pseudoisochromatic plates test by Terrace L. Waggoner at Testing Color Vision (Colblindor discount code: «colblindor») and tell me what you think about it.

Most people relate the term color blindness test to the dotted pictures or even to the name Ishihara.

But this is not the only one, not the best one, definitely not the most current one, and most often an unsuitable test which is still used all around the world.

This part of the Color Blind Essentials series focuses on the different possibilities to test color vision, how they work, what they can be used for and lists some of the well-known and used tests. There will be no conclusive enumeration as there are just to many tests around, with a lot of them not available anymore but still in use.

First color blindness tests

Already in the 17th century Turberville found differences in some individuals color naming, which was definitely one of the first color blindness tests. About one hundred years later John Dalton described in detail his color vision and also tested other people with some colored ribbons which had to be named as well. At this time most often color vision deficiency was reported simply by subjective descriptions.

In 1837 August Seebeck used some more advanced technique. He used a set of more than 300 colored papers and let people match or find a closely related color to a sample color. This type of color vision test abandoned the naming of colors, which differs a lot between test persons. Through Seebeck’s color blindness test two different types of red-green color blindness and a broad severity scale were discovered. Holmgren adopted this kind of test in 1877 by using skeins of wool. The Holmgren wool test was widely used and even commercially available more than one hundred years later.

The following two developments happened around the same time. They led to modern color vision deficiency testing.

• John William Strutt Rayleigh developed a precise color matching test. This match—still known as Rayleigh match—is not only the base of modern anomaloscopes but also made him discover dichromatism and anomalous trichromatism.
• Dr. J. Spilling published the first painted set of pseudoisochromatic plates. They were the predecessors of the famous Ishihara plates, which were produced the first time in 1917.

The different color vision deficiency test forms

Anomaloscope

Anomaloscope

The anomaloscope provides the most accurate possibility to test the severity of color blindness and distinguish between dichromats and anomalous trichromats.

It is based on the Rayleigh match: A mixture of red and green light sources has to be matched with a yellow light source. Through the matching range it is possible to discover all different types of red-green color vision deficiency. Some of the anomaloscopes also include the Moreland match (blue-green) to test for tritan defects.

If you are a dichromat you will be able to make a match for all red-green mixture ratios. Anomalous trichromats don’t accept the normal match and the distance of their match indicates the severity of their deficiency. On the other side, if you suffer a protan vision deficiency you will use much more red to match the colors compared to people with a deutan defect, which use more green in their mixture.

In 1907 the Nagel anomaloscope was introduced and is still known as one of the best. Unfortunately it is not produced anymore. Other well known instruments are the Neitz anomaloscope, the HMC (Heidelberg Multi Color) anomaloscope or the Pickford-Nicolson anomaloscope.

Pseudoisochromatic plates

Pseudoisochromatic plates are the most famous type of color blindness test. Most people know them under the name Ishihara plates test, because Dr. Shinobu Ishihara was one of the first persons who designed a very reliable plate test, introduced in 1917. He produced different test sets. Ishihara plates are still widely used all around the world.

The copunctual points build the source for this type of color vision test. The fact that colorblind people can’t distinguish colors along the confusion lines is used to build a pattern of differently colored dots. If you are color blind you won’t spot the dots which are shifted along the confusion lines and therefore numbers, letters, lines or anything else can be hidden from you.

There exist four different type of plates:

• Vanishing design: Only people with good color vision can see the sign. If you are colorblind you won’t see anything.
• Transformation design: Color blind people will see a different sign than people with no color vision handicap.
• Hidden digit design: Only colorblind people are able to spot the sign. If you have perfect color vision, you won’t be able to see it.
• Classification design: This is used to differentiate between red- and green-blind persons. The vanishing design is used on either side of the plate, one side for deutan defects an the other for protans.

Why can colorblind people see something which is not visible for people with perfect color vision?
If you are colorblind you are not distracted by hue differences along the confusion lines. You will be more focused on lightness differences. This two different facts are used to design the hidden or invisible plates.

Besides the most famous Ishihara plates exists in a standard version of 38 plates, a shorter version of 24 plates and a concise test containing 14 plates. Ishihara plates can only be used to classify red-green color vision deficiencies. Tritan defects can not be evaluated by these tests.

The other well known pseudoisochromatic test plates are the 24 HRR plates by Hardy, Rand and Ritter. This test was first produced in 1954 and can be used the classify all three different forms of color vision deficiency. There also exist a lot more of such tests but none of them is widely used. Even some electronic vision test equipments include certain pseudoisochromatic plates as a quick color vision test. But none of them is very accurate to get a concise test result.

Arrangement tests

Arrangement tests are also based on the theory of copunctual points. In contrast to the static pseudoisochromatic plates where you have to spot a path or number, an arrangement test is dynamic.

D-15 Color Arrangement Test

Every such test consists of a certain number of colored discs or plates which have to be arranged in the correct order, starting from a pilot plate. The colors are chosen around the white point and because colorblind people can not distinguish colors along certain lines they will arrange the discs completely different compared to somebody with normal color vision.

The most well known test was introduced by Fransworth in the forties of the last century and is called Farnsworth D-15 arrangement test. As the names suggests this test includes 15 colored plates which have to be arranged in the correct order. You can try an online version of this test right here at Colblindor: Color Arrangement Test.

Some other well known tests in this category are the Lanthony desaturated D-15 test, which is used to classify milder forms of color blindness and the Farnsworth-Munsell 100 hue test. This test includes 100 different plates which have to be arranged in batches of 20 plates. Unfortunately the results are not that better compared to the 15 plates versions.

Lanterns

The last well known type of tests was introduced by railway companies which discovered, that some of their employees couldn’t distinguish certain signal lights. Lantern tests are specially designed to simulate signals and are therefore most often used as vocational tests.

Compared to the other tests with lanterns you are testing the required ability directly. They are robust and have a high practical value. On the other side you can’t reveal much of the nature and severity of the color vision defect.

• Holmes-Wright lanterns: This lantern includes two different green, two red and a white light. Lights are shown in pairs of two, low or high brightness, either vertically or horizontally aligned. The test person is asked to name the colors.
• Farnsworth lantern (Falant): This is the standard test in the US. It is comparable to the Holmes-Wright lantern but is specially designed to pass people with a mild form of color vision deficiency.
• Beyne lantern: France.
• Giles-Archer lanterns: UK.
• Edridge-Green lantern: UK.

The following table shows an overview of the different main test types for color blindness and compares them in certain dimensions. Every test type is graded from (-) not capable to (+++) excellent capability.

Unfortunately Ishihara plates are used much to often to check for occupational suitability. Lanterns or certain arrangement tests would be much better in this case. And if you like to have a precise diagnosis of your color vision deficiency there is no way around an anomaloscope.

The future of color vision testing

Today in our digital world one might think, why don’t we have some simple computer based color blindness test. Unfortunately this is not as simple as it looks like. There are two main problems:

1. Computers displays just make use of three main colors red, green and blue (RGB). Every other color gets mixed from those three colors. The anomaloscope and lantern tests use different light sources which can’t be simulated by a display.
2. Every computer display has a different color range it covers, little differences in light sources, different brightness and more. This causes different test results. Only calibrated computers can be used to perform such computer based tests.

The City University in London developed a computer based color vision test which is also based on the same principal as pseudoisochromatic plates and arrangement tests. The main difference is that the colors are constantly changing which gives some really good results. Just recently they used their test to check color vision in pilot candidates and it looks like as the Color Assessment & Diagnosis Test (CAD Test) could become a standard screening instrument for color vision testing. At least for certain professions, where color vision is critical but people with a mild form of color vision still perform perfectly.

There are also some genetic screenings available. But even such a simple impairment as color blindness is not easy to detect in the genes. So every genetic test always needs some physical tests in parallel to get a proper and concise test result.

Color naming would be a very simple test to identify color blindness. But for most cases this is just to simple, to unspecific and not reliable enough. Therefore color naming can be used to check if you have a moderate to strong color vision deficiency but not for a detailed classification of your color vision deficiency.

The next part of the Color Blind Essentials series focuses on how color blindness can affect your everyday life.

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