To be colorblind is one thing. To know which type of color blindness you are suffering from is something different. Particularly red-green color blindness, the most common form of color vision deficiency, has several subtypes which are not easily distinguishable.
Yesterday I received the following question which I would like to quote here and hopefully give you some answers thereafter.
My husband is red-green colorblind, but we don’t know which type. What is the best way to go about finding out protanopia/protanomaly or deuteronopia/deuteranomaly? We’ve seen some of the test on the internet, but what do you recommend?
Maybe you are in the same position as the person described above; so let us dive in and find some answers for you.
Before I give you some advice on the how and why I would like to explain the technical terms above and set them into relation to red-green color blindness.
Red-green color blindness terminology
There are two different axis which you have to take into account. The first axis distinguishes if you have problems with your long (L) or medium (M) wavelength cones. The L-cones are red sensitive and are—if malfunctioning—the source of red-blindness (protanopia) and red-weakness (protanomaly).
On the other side are the M-cones, which are more sensitive to green colors. If your M-cones are absent or not working properly you are either green-blind (deuteranopia) or green-weak (deuteranomaly).
The other axis tells you about the severity of your color vision deficiency. Either you are a dichromat (protanopia/deuteranopia) and therefore you have only two different types of color receptors in your eyes. Or you have three different types of color sensitive cones, like somebody with normal vision, which is called anomalous trichromacy (protanomaly/deuteranomaly).
Finding out your subtype of color blindness
If you want to know for sure on which sides of the axis your color blindness sits, you have to go to a doctor for a check-up. But not just any doctor can do the job for you. Before your consultation you might like to check the following two points:
- Your doctor should be an eye specialist.
- He should have different possibilities to test for color blindness (check this in advance).
There are different color blindness tests available and every test has its advantages and weaknesses. If you put everything just on one test you might get a wrong conclusion. The list below gives you an impression of what tests could be available when taking your tests at an eye specialists place.
- Pseudoisochromatic plates like the well known Ishihara plates tests.
- Anomaloscope; Neitz-, Nagel- or also Heidelberg Multi-Color-Anomaloscope.
- Lantern tests as the Farnsworth LT or the Holmes-Wright LT.
- City University tests.
- Arrangement test like the well known D-15 Farnsworth or the Farnsworth-Munsell test.
Every single test can play its part when you want to find out which subtype of color blindness affects you. Different tests together will give you an overall picture and a very good and reliable result when properly accomplished.
If you have your reasons not to go to an eye specialist you can try to do some color blindness tests by yourself. In that case you have to know, that these results will never be as reliable as when you consult your doctor. You also may not have the possibility to do many different tests like the ones listed above, as they are not publicly available.
There are many places where you can buy such tests like the Ishihara plates and accomplish the test at home. But this is usually way to expensive and as you are not trained in interpreting the results I don’t recommend it to you.
On the other side you can take some online color blindness tests. Before you head on, take your tests and think you know what subtype of color blindness is your one, let us step back and have a look at the difference between an online and a hardcopy test.
- Online tests are often scanned images. Because printed and display colors are very different and each scanner has its own color calibration, this images can look quite differently on screen. Therefore the results would not be the same and are less reliable.
- Every computer display is different. So if you take an online color blindness test using different displays the result could also vary.
- A computer display has a so called gamma correction. If contrast and brightness of your monitor or not very well adjusted this could also alter your test results.
Being aware of all that you can head on and try out some tests to find out more about your color vision deficiency. To get a more detailed analysis of your red-green color blindness I recommend you the three following steps.
- Step 1: Take the Ishihara plates color blindness test and if this one is not enough check out the other source about Ishihara plates test. Through this pseudoisochromatic plates test you get an overall feeling of your color blindness but not a very accurate result.
- Step 2: Take the color blindness test based on confusion lines. There are three different tests (protan/deutan/tritan) to choose from and when you write down your results you get a good understanding of which subtype of color blindness gives you the biggest problems.
- Step 3: Take the D-15 Farnsworth Arrangement Test. These results will tell you more about the severity of your deficiency. If you have real problems accomplishing the D-15 test you are most likely a dichromat. Otherwise you supposably have a anomalous trichromacy.
Combining together the results of those color blindness test should give a more accurate knowledge about your color vision deficiency. Through step 2 you should be able to place yourself on the red-green axis. Either you are more on the red side (protanopia/protanomaly) or on the green side (deuteranopia/deuteranomaly). But be aware, if you have problems with one of those tests you will also have some problems with the other one, because the confusion lines of red- and green-blind or -weak persons are very close together.
Step 3 tells you more about the severity. If you are a dichromat and therefore have only two distinct types of color receptors in your eyes, you will have severe problems to accomplish the task arranging the colors in the right order. Otherwise you most likely have some weak form of color blindness. This shows you your position on the second axis.
Putting together step 2 and step 3 should give you a quite good overall impression of your color blindness. But as I said, there are many limitations to be taken into account and no online test will ever replace a consultation at the eye specialist.
I hope I could reveal some insights about red-green color blindness and help you to find out more about your color blindness in detail. If you did like this article you can either bookmark it with the button below or subscribe to my RSS feed to get fresh updates on color blindness.
Do you have any information on something called an X Chrome lense that corrects red/green color blindness?
Jon, at The Way to Cure Color Blindness? you’ll find in the comment section a list of companies offering such lenses or glasses.
Unfortunately I’ve never tried them and can’t tell you any further details about them.
I was tested in my teens then in my twenties and always tested positive for red/green color blindness but I had no idea what type I was.
Last time I was tested was through my eye doctor and I also tested high on the depth perception test (is that normal?).
I’m female and my father is color blind but I don’t know what type he is. I do know he can’t dress himself well when I was young and my mom had to help him pick colors because he would mismatch really bad.
Now my mother’s side of the family carries the gene, so I figured if I tested positive for red/green color blindness all these times (it was more than twice, my art teacher insisted I be tested again in my teens) that my mother must be a carrier of the gene. Right?
I also never seem to pass the online tests I always took for fun.
But wow, I totally aced the test here. How is that possible? Could I have tested wrong all these years? Is it really possible?
Melissa, you are right about the genes. You must have inherited from both – your mother and your father.
Concerning color blindness tests, you should rely on the test results from your eye specialists. Online tests are never as accurate.
It sounds like you don’t really feel like a colorblind woman. In this case I suppose you are only slightly colorblind and because of that you might get some positive results in online tests.
I’ve been diagnosed with red-green color blindness 2 times in my life due to failing the Ishihara test.
I do however pass the confusion lines test (step 2) and the D-15 Farnsworth easily (step 3) on this site easily.
In the confusion lines test trianopa gave me 97/100 correct, deuteranopia 96/100 correct and to my surprise I got 100/100 protanopia which I found to be the hardest one. I did them really fast too, my average response time was 2s.
The D-15 I found very easy and got a normal vision result on that one as well.
Yet somehow I have a bit of trouble with the ishihara.
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Why is red/green color blindness more common than blue/yellow
I took an Anomaloscope test and the results were that I was Green deficient, which means I have a problem with my M-Clones. The problem is however, the Dr. said I was Dichromat and partly in between Deuteranopia and Deuteranomaly? Is this possible? For me to be Deuteranomaly dont I have to be Anomalous trichromacy?? Is he pulling my leg? I dont undertand what is going on?
Is there such thing as Dischromacy – Deuteranopia/Deuteranomaly ?? Thnx for the answers.
Nick, either you are a dichromat which would be in your case deuteranopia. And otherwise you are an anomalous trichromat, in your case deuteranomaly.
You are completely right. There is nothing else, nothing in between. Deuteranomaly can show up in all kinds of severity, but it is still deuteranomaly.
I wonder why your doctor has the best tool available to test for color blindness (the anomaloscope) and can’t interpret the results.
Thank you very much Daniel, I am going to get to the bottom of it.
BTW, does this mean anything to you
Rayleigh — Dynamic — 6 Test
Right – CMP,50 SR,05 to 95
AQ,19.0 B,15 to AQ,0.05 B,15
Left – CMP, 50 SR,04 to 96
AQ, 24.0 B,15 to AQ,0.04 B,15
Any help will be greatly appreciated ….
I recognise Rayleigh’s name, he was an early researcher into optics. I don’t recognise the test or understand how to interpret the results. Sorry.
Nick, here is what I found out:
Right – Left: your right or left eye.
CMP: calculated mid point (match between yellow and red-green mixture)
SR: (setting) matching range
AQ: anomalous quotient
B: I have no idea.
As your matching range goes almost over the whole spectrum (0 – 100) you are according to this test a dichromat.
AQ for normal vision is between 0.76 and 1.42, which is a ratio between your results and results from people with normal vision.
As far as I can tell, the results don’t tell anything about if you are a deuteranope or protanope. But as I could read you know this already from you eye specialist.
Thanks for taking the time Daniel. The information you have provided has been incredibly helful!
hi im a redgreen deficient guy, recently heard that tinted eyeglasses help
took the d15 test and was labelled a deutan. re-did the test looking through red cellophane and results much better (almost a ring) but still not normal
what’s your take? thanks
Do you know if its possible to be both deuteranomalous and protanomalous? I’ve taken every little test I can get my hands on, and I keep coming to the conclusion that I’m just slightly weak on both. Is this possible? Or can you only be affected by one and not the other?
Jeremy, it’s not that easy to find the correct type of color vision deficiency. Usually you’re not suffering from both at the same time, but there is some mixture of both genetically possible.
Hi I found out last week that I am moderately deuteranomalous and protanomalous from my optician.
I know a bit about both of them separately- deutan being green deficiency and protan red deficiency- but does that mean I don’t see any colour with either red or green in it properly?