How to take the test to confirm color blindness

Color blindness tests help confirm the presence of this change in vision, in addition to helping the doctor to identify the type, which ends up facilitating treatment. Although the color test can be done online, the diagnosis of color blindness must be confirmed by an optometrist.

Identifying color blindness in childhood is important for the child to feel more integrated in the classroom, increasing school success. In the case of adults, knowing their own type of color blindness helps to adopt strategies to know how to combine colors in clothes or decoration, or to differentiate between green and red apples, for example.

Better understand what color blindness is and what types exist .

Available color blindness tests

There are 3 main tests that can be used to help diagnose color blindness. They include:

  • Ishihara test: it is done through the observation of dotted cards of several different shades, in which the person must mention which number he can observe;
  • Farnsworth test: helps to diagnose acquired color blindness and is performed using four plastic trays, with one hundred capsules in different tones, which the observer must organize by color, in 15 minutes;
  • Holmgreen Wool Test: this test assesses the ability to separate different wool threads of different colors by color.

1. Online test for adults

One of the tests that can be most easily done at home to try to identify a case of color blindness is the Ishihara test. For this, the following image must be observed:

What should be noted in the images is:

  • Image 1:  the person with normal vision observes the number 7;
  • Image 2:  number 13 must be observed to indicate normal vision.

Although this test may indicate the risk of someone having color blindness, it does not serve to make the diagnosis and, therefore, you should always consult an optometrist.

2. Children’s online test

The children’s Ishihara test consists of observing geometric shapes and paths, because children do not always know the numbers, although they are able to see them.

So, to do the test with the child, you should ask them to observe the following images for about 5 seconds and to try to follow the paths presented with your finger.

When the child cannot report what he sees, nor can he follow the shapes over the image, he may indicate a case of color blindness and, therefore, it is advisable to consult the pediatrician and an optometrist.

Other tests that can help

In addition to these tests, the doctor may also use other methods, such as the electroretinography exam, for example, to assess the electrical response of the eye to light stimuli. 

The milder cases of color blindness in most cases may not be diagnosed, since the person does not feel much change in their day-to-day and, therefore, also does not seek medical help. 

When you suspect color blindness

Usually from 3 years of age it can be suspected that the child is colorblind when he is not able to correctly identify the colors, but usually his diagnosis is made later, when he already collaborates better with the test, better identifying the figures and the test numbers. 

It is possible to begin to suspect the diagnosis when the child is unable to respond correctly when asked about a color or paints drawings with the wrong colors, such as painting a pink carrot or a yellow tomato, for example.

In addition, another common sign of color blindness appears in adolescence when the young person is not able to coordinate colors correctly. Thus, it is recommended to consult the ophthalmologist before the child enters school, to make the appropriate vision tests and diagnose possible problems in addition to color blindness.

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