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Colorblindness tests aim to assess a person's ability to distinguish different shades of color, which can be done using cards, colored capsules and wool yarn, for example. Although the color test can be done online, the diagnosis of color blindness must be confirmed by an ophthalmologist.
Color blindness is a visual alteration in which the person cannot distinguish colors very well, especially red and green, which may be due to genetic alterations or a consequence of damage to the eye structures. Learn more about color blindness.
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 them to adopt strategies to know how to combine colors in clothes or decoration, or to know how to differentiate between green and red apples, for example.
The main tests available that can be used to help diagnose color blindness are:
1. Ishiara's Test
The Ishiara test, also known as the color sense test, is one of the main tests used in the investigation of color blindness. In this test, the person is presented with cards with circular images and dotted with different shades, and the person is instructed to say which number they are observing.
The person with color blindness usually has difficulty identifying the number present on the cards.
2. Farnsworth Test
The Farnsworth test is a more accurate test and aims, in addition to identifying color blindness, to assess the type and degree of alteration.
In this test, there are 4 trays containing small discs with different colors and with a reference disc at the end. Thus, the person is asked to arrange the disks in the trays according to the reference disk. People with color blindness have greater difficulty in performing this activity, and in some cases they may have errors in the entire test or just in some color, which indicates the severity of color blindness.
3. Holmgreen Wool Test
The Holmgreen wool test consists of asking the person to separate the wool yarns, which have primary colors or slightly different shades, in a predetermined order that will be indicated by the doctor performing the test.
Electroretinography is an examination that can be performed by the ophthalmologist and whose objective is to verify the electrical response of the eye to light stimuli, which can be useful in the detection of other ocular alterations, in addition to color blindness.
Online test for color blindness
Online tests can be performed as "preliminary diagnostic tests", and it is important that the diagnosis is confirmed by the doctor.
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 should be observed:
What to observe in the images is:
- Image 1: the sighted person observes the number 7;
- Image 2: number 13 should be noted to indicate normal vision.
Although this test can indicate the risk of someone having color blindness, it is not useful for making a diagnosis and, therefore, you should always consult your doctor.
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, they should be asked to observe the following images for about 5 seconds and try to follow the paths presented with their finger.
When the child cannot refer to what he sees, nor can he follow the shapes over the image, it may indicate a case of color blindness and, therefore, it is advisable to consult a pediatrician and an ophthalmologist.
When you suspect color blindness
It is possible to suspect color blindness, usually from the age of 3, which is more or less the age at which the child begins to learn colors. Thus, in the case of color blindness, the child cannot or has difficulty making the distinction. However, the diagnosis is only confirmed in older children, when they are able to collaborate better with the tests, better identifying the figures and numbers of the test.
Thus, when color blindness is suspected, it is important that the ophthalmologist be consulted, as tests are performed that help confirm the diagnosis and strategies that can promote the person's quality of life can be indicated.