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What is color blindness and how Eye-Able helps

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Bild eines Heißluftballons mit vielen Farben

Definition of color weakness

Color perception is based on the ability to distinguish between the three primary colors red, green and blue. Man mixes all other colors from these primary colors. Special light-sensitive cells are responsible for color vision: the cones, which are located in the retina. If the perception of one of these basic colors is limited, one speaks of one color weakness, such as red-green blindness and green-blue blindness. If, in the worst case, you can no longer see one or more colors at all, you speak of one color blindness.

men and color weakness

The following figures show how many people are color blind: around eight percent of all men but only around 0.4 percent of women suffer from it, reports the professional association of ophthalmologists (BVA). The red-green weakness is the most widespread with about 50 percent of all cases. So we are alone in Germany about 3.5 million people affected. Total color blindness, in which those affected can only distinguish between light and dark, is much rarer - only one in 100,000 people suffers from it. In addition, their visual acuity is reduced and they suffer from strong glare [1].

The following images simulate how color blind people see the world. The original image can be seen as well as its change in red, green or blue blindness:

Figure 1: Simulation of different color weaknesses. Original (top left), red blindness (top right), green blindness (bottom left) and blue blindness (bottom right)

Possible problems when operating a website

It becomes difficult for people with color blindness, when a specific meaning is associated with a color. Due to color weakness, differences between different colors can become blurred, making differentiation more difficult. For example, this could be the colors of different data in a chart. The problems people encounter here are shown in Figure 2:

Figure 2: On the left the unchanged diagram, on the right with simulated green blindness

While all colors are easily distinguishable in the left unchanged image, the difference becomes much more difficult for a person with green blindness. The meaning of the color of buttons, the marking of areas on maps or general colored areas can remain hidden to people with color deficiency.

How Eye-Able Adjusts Colors

To help people with color weakness, Eye-Able has included the color weakness feature. As shown so far, there are different types and characteristics of color weaknesses. Therefore standing in Eye-Able altogether six different modes to disposal. There is a specially adapted process for each color weakness, the possibility of completely removing the colors and increasing the contrast or color saturation. The intensity can be adjusted for each of the functions. 100% mean a correction for color blindness, while smaller values compensate for color weakness. In order to make color differences more visible again for those affected the affected color areas shifted towards visible colors. For example, when correcting a red deficiency, the red colors are shifted towards the blue color spectrum. To do this, Eye-Able adjusts all visible colors on the website. The following figure shows the use of this function:

Figure 3: Representation of the color correction based on Ishihara test images (Source: Wellcome collection CC BY 4.0)

As can be seen in Figure 3, color differences can be better displayed again for those affected by color correction. In addition to the respective color weakness modes, increasing the contrast or color saturation can also lead to an improvement. The following traffic light shows another example of how Eye-Able color correction can make color differences visible again:

Figure 4: Traffic light with normal colors (left), traffic light for people with red color weakness (middle), traffic light for people with red color weakness after eye-able correction (right)

sources and further information

For those interested, here are some of our sources and further information material:

[1] https://focus-arztsuche.de/magazin/gesundheitswissen/farbfehlsichtigkeit-und-farbenblindheit-erkennen

[2] https://www.sehtestbilder.de/sehtest/

You can also do an eye test here. Caution: An online eye test can therefore only ever give a clue. If you suspect color blindness, please consult an ophthalmologist.

[3] Françoise Viénot, Hans Brettel and John D. Mollon
Digital video color maps for checking the legibility of displays by dichromats
Color Research and Application, 24(4):243-252
, 1999.

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