Online Anomaloscope doesn’t Differentiate Red-Green Color Blindness

RGB Anomaloscope

The RGB Anomaloscope can be used to check if you are suffering from red-green color blindness or not. Unfortunately it is not possible to differentiate between the different forms of red-green color vision deficiency.

Our online anomaloscope is based on matches between yellow and a mixture of red and green—like the real anomaloscope. The matches you make can tell you, if you are suffering from red-green color blindness or not (because if you are not colorblind, you can’t make any matches).

In an earlier update of the anomaloscope (Severity Upgrade), I found an interesting looking pattern in the matching colors. We had two peaks which looked like a pattern for differentiating between red- and green-blindness.

  • Red-blindness shifts the peak of red sensitive cones towards the peak of the green ones. Because of that you have problems in differentiating certain colors and also your red starts looking much darker.
  • Green-blindness works the other way around. The peak of the green sensitive cones is shifted towards the red peak. This causes a very similar form of color blindness, but in contrast to red-blindness, red doesn’t start to look darker.

Over the last month I tried to evaluate this pattern in further detail while asking testers to declare their type of color vision deficiency, if known. Unfortunately I couldn’t find any pattern at all.

RGB Anomaloscope Greenblind
RGB Anomaloscope Greenblind

This diagram shows the number of people taking the test, which declared to be green-blind and matched a certain yellow value (horizontal axis) to either green (#00FE00) or red (#FF8000).

The above diagram can’t tell us anything about a pattern. We have to compare it to the diagram, which is based on the numbers from people who declared to be red-blind.

RGB Anomaloscope Redblind
RGB Anomaloscope Redblind

I adjusted the vertical axis in this diagram, as there were more people who declared to be red-blind. So the two diagrams can be compared 1 : 1.

Unfortunately the two diagrams Greenblind and Redblind look pretty much the same. This shows me, that my first assumption was wrong and this version of the RGB anomaloscope can not differentiate between red and green color vision deficiency.

3 responses on “Online Anomaloscope doesn’t Differentiate Red-Green Color Blindness

  1. Robert Jackson

    Thank you for this test – folk have told me I have a problem with my colour vision and I have seen the Ishihara tests yet I do see quite subtle colours.

    When I did your test, though, I found it really easy to match all of the colour squares <> so those folk are right. I’ll be interested to know eventually whether my weakness is in the red or in the green. I found at school the teacher writing on a blackboard in red chalk was impossible so I suspect redis my problem though I still believe I know red when I see it.

    Thank you again.

  2. Tomas Gradin

    I think you have overlooked a simple fact: most people’s computer screens do not show proper colors, since they haven’t been properly calibrated. This would probably affect the test.

  3. Adib Mohd Satali

    yes you are rite Gradin about the color produced, but the main point is we need to match the color. if the color does not show as the proper color it doesnt matter.