If you are colorblind it is not just about being colorblind or not. There are many different types and characteristics of color vision deficiency which you can suffer from. Color blindness is an umbrella term for all those different forms—and not even a good one.
I’m 13 years old and have been told I am red-green colour blind but only slightly. I have done research and taken MANY colour blind tests. But I’m still confused because how can I be slightly colour blind? Either I am or I am not. I have failed most of the tests I have taken and my optician has told me I am slightly colour blind towards red-green (the most common) but want to know how I am only slightly colour blind and what the scientific word for being slightly red-green colour blind.
First of all, you shouldn’t rely on the color blindness tests available online. These tests are just used to give you a feeling what kind of color blindness you are suffering from and how severe it is. But because every computer display can have different color adjustments they are not 100% reliable.
This young reader says, that either you are colorblind or you are not. This is true and false. If you go to your eye specialist and take a color blindness test, he will tell you if you have normal color vision or not. So yes, either you are colorblind or not.
But he can also tell you, what type of color blindness you are suffering from and the approximate severity of it. There is a whole terminology of color vision deficiency which I don’t wont to list here on the whole. Just the most important facts.
- Types of color blindness:
- Red-green colorblind: This is the most common form and according to its name, causes the biggest problems with red and green. There are two different subtypes: Red-blind (or -weak) and green-blind (or -weak).
- Blue-yellow colorblind: This type of color vision deficiency is not so often seen and actually the colors blue and green (not yellow) are the problem area.
- Completely colorblind: A very uncommon type which makes you see only in shades of gray. Unfortunately a lot of people think that every colorblind person can only see in shades of gray.
- Severity of color blindness:
- Anomalous trichromat: You have still three different types of color receptors as someone with normal color vision. But one of them is slightly shifted in its peak of sensitivity and therefore you can’t see the same broad color spectrum as others.
- Dichromat: Here only two of three color receptors (cones) are working. You have to mix your perceived color just with two signals compared to three with normal color vision. The color spectrum is strongly reduced.
- Monochromat: Either no color receptors are working (rod-monochromacy) or just one of them (blue-cone monochromcy). Anyway you will have either just grayscale vision or a very very restricted color vision.
This means, that is possible to suffer from any possible severity of color blindness. This because the three different color receptors have a highest peak of sensitivity. With an anomalous trichromacy, one of those peaks is shifted towards another one; usually the red peak towards the green or vice versa.
Because of that shift and the resulting peaks which are closer to each other, less information is available to mix up the final color in your brain. And this makes you either slightly colorblind (peaks still far apart) or more severely colorblind (peaks coming closer).
The academic term for a slight red-green color blindness is either protanomly (red-weakness) or deuteranomaly (green-weakness). Both types are a subtype of red-green color blindness and a form of anomalous trichromacy.