The color vision is checked mainly by means of special panels with different colored dots (Ishihara panels); The test is feasible from about the age of 3 years. Indications are that the affected child has difficulty painting with colors or recognizing traffic lights. But most of the time, those affected quickly succeed in compensating for this: they simply learn the arrangement (top = red, bottom = green) or the colors of their familiar objects by heart.
Those with a color weakness do not see gray, but simply perceive many shades of color differently - as if they had fewer source colors available in a color box for mixing than a normal-sighted one. This has not only disadvantages - some are perceived better or more contrast. Individuals with total color blindness often suffer from severe glare sensitivity and impaired vision.
What can one do about color vision deficiency?
There is no therapy for congenital color disorder, a correction is only conditionally possible:
- People with total color blindness often wear dark sunglasses. Depending on the light conditions, special edge filters are used for these glasses, which filter certain colors out of the sunlight. Loupes or small binoculars allow the reading of small letters or looking into the distance.
- For people with a red-green weakness, there are special lenses that filter out certain color spectra differently; however, this changes the perception of other colors. Quite new is a computer-aided individually adjusted to the degree of ametropia color correction glasses to compensate for the red-green weakness - this is, however, not yet ready for mass production.
- There are devices that can detect colors. They send a small beam of light to the object and measure how much light comes back. This allows the device to tell what color an item has. The practical benefit is however controversial.
Depending on the nature of color vision deficiency, this can restrict the choice of profession - for example, people with a color weakness may not become a pilot, platoon commander or captain.