There are people who learned from a young age that certain colors are called red, green, or blue, but never wondered whether others saw them exactly the same. Color blindness can go unnoticed for years because, when present from birth, the person simply incorporates that perception as part of their usual way of seeing the world.
Difficulty can appear in seemingly simple situations such as choosing an outfit, interpreting a chart, distinguishing certain foods, or recognizing colors in school materials. And although in most cases it does not cause major problems in daily life, there are signs worth knowing and, especially, changes that require an ophthalmological consultation.
On Daltonism Day, Dr. Lucas Viana (M.N. 106531), an ophthalmologist specializing in neuro-ophthalmology, explains what lies behind this alteration of color perception and how it is diagnosed.
What is color blindness and how are colors perceived?
To understand what happens, one must first know how color vision normally works. When light enters the eye, it reaches the retina, where cones reside—specialized cells that respond to different wavelengths associated mainly with red, green, and blue.
That information travels to the brain, which combines it to generate color perception. When one or more types of cones do not function as usual, certain hues can become more difficult to differentiate.
“Color blindness can present itself in different forms and affect color perception in variable ways. In most cases, the person has difficulty differentiating certain colors or hues, and may live with this condition for years without knowing it,” explains Dr. Viana.
The most common form is related to difficulty distinguishing some shades of red and green. There are also less common alterations that affect the perception of combinations related to blue and yellow.
The intensity can also vary. Some people have a very mild difficulty differentiating certain hues, while others present a much more pronounced alteration. The complete absence of color perception, known as acromatopsia, is rare.
Why is color blindness more common in men?
Genetic color blindness is far more frequent in men. According to the National Eye Institute, approximately 1 in 12 men have some form of color perception alteration, while in women the proportion is considerably lower.
The explanation lies in genetics. The genes associated with the most common forms of color blindness, particularly those affecting red-green perception, are linked to the X chromosome.
Men have only one X chromosome, while women have two. Therefore, certain genetic alterations are more likely to manifest in men.
How to know if a person is color blind?
One characteristic of congenital color blindness is that it may not attract the attention of the person who has it. If someone has always perceived colors in that way, they may have no point of reference to know that a difference exists.
In children, some signs may appear during the learning of colors or during school activities that require identifying different shades. In adults, the difficulty may become evident when interpreting maps, charts, signs, or certain color combinations.
However, a single situation is not enough to determine that someone is color blind. Diagnosis is made through a chromatic vision assessment.
One of the best-known studies is the Ishihara test, which uses plates formed by circles of different colors within which numbers or shapes appear. Depending on each person’s color perception, those numbers may be more or less visible.
A professional evaluation can determine whether an alteration exists and what type it is.
The difference between being born color blind and developing it in adulthood
Not all color blindness is hereditary. Although the majority of cases has a genetic origin and is present from birth, color perception can also change over the course of life.
An acquired alteration may be related to problems affecting the retina, the optic nerve, or certain areas of the brain, among other causes.
Therefore, there is a fundamental difference between someone who has always seen colors in a certain way and a person who notices a sudden change in their color perception.
“When a person notices a change in how they perceive colors, it is important to consult with an ophthalmologist. It is not the same as an alteration that has been present since birth as opposed to a change acquired later,” says the specialist.
And he adds: “It is essential to identify the cause of the acquired color perception alterations, as this change can be associated with situations of different nature and clinical relevance.”
In other words, if colors start to look different from one moment to the next, do not assume it is simply color blindness. A consultation allows you to investigate what is causing that modification.
Does color blindness have treatment?
Currently, genetic color blindness has no cure. However, this does not mean it prevents living a normal life. Most people learn to recognize certain situations and develop strategies to cope with them.
It can be helpful, for example, to pay attention to the position of traffic lights rather than relying solely on the color, to use apps that identify tones, or to request that graphs and visual materials incorporate cues beyond color.
“The important thing is that the person understands how they perceive colors and can recognize how this may influence their daily life,” explains Dr. Viana.
In children, moreover, knowing this condition can help avoid unnecessary confusions during learning and allow teachers and families to adapt certain materials when needed.
The key is to differentiate a lifelong trait from a new change in color perception. In the latter case, an ophthalmological consultation is the first step to find the cause and receive the appropriate guidance.
Source: Dr. Lucas Viana – M.N. 106531, Ophthalmologist.
