Colour Blindness – How Colour-Blind People See and Which Colours They Can't Tell Apart

The ability to distinguish colours is an important part of how we perceive the world. Thanks to millions of light-sensitive cells in the retina, we can see a vast number of shades, find our way around and get extra information about the objects around us. However, some people perceive colours differently from the usual norm. This condition is called colour blindness.

Many people mistakenly believe that colour-blind people see the world only in black and white. In fact, this is a common misconception. Most colour-blind people still see colours but have difficulty telling certain shades or colour combinations apart. To understand this condition, it is important to know whether colour blindness is a disease or an inborn trait, what forms of colour vision deficiency exist, and whether they can be corrected.

What is colour blindness

Colour blindness means an impaired ability to perceive or distinguish certain colours. The main cause lies in how the cones work — special receptors in the retina responsible for colour vision.

Normally, a person has three types of cones, sensitive to the red, green and blue parts of the light spectrum. If one type of receptor is missing or does not work properly, various colour perception disorders occur.

Most often colour blindness is an inborn trait and is inherited. Much less common is acquired colour blindness , which develops as a result of eye diseases, nervous system disorders or injuries.

Why colour blindness develops

The main cause of the inborn form is genetic changes that affect how the retinal cones work.

However, there are other factors that can impair colour perception:

• retinal diseases;
• optic nerve damage;
• age-related changes in the eyes;
• diabetic retinopathy;
• glaucoma;
• after-effects of head injuries;
• brain tumours;
• certain medications.

This is why colour vision problems are not always inherited. In some cases the problem appears in adulthood and requires an examination by an ophthalmologist.

Types of colour blindness

Modern ophthalmology distinguishes several forms of colour vision deficiency. The different types of colour blindness differ in which shades are hard for a person to perceive.

The main forms include:

• protanopia;
• deuteranopia;
• tritanopia;
• monochromacy;
• anomalous trichromacy.

Each type affects how a person perceives the world in a different way.

Protanopia

In protanopia, perception of the red part of the spectrum is impaired. Red shades appear less vivid, and some colours become hard to tell apart.

People with this condition may find it difficult to distinguish:

• red from brown;
• red from green;
• orange from some shades of yellow.

Other colours may be perceived almost normally.

Deuteranopia

One of the most common forms is deuteranopia. In this case, the receptors responsible for perceiving green do not work properly.

Patients often confuse green and red shades and perceive some colour combinations as almost identical.

Many people wonder whether there is a treatment for deuteranopia . Today it is not possible to fully eliminate the inborn condition, but special lenses and modern technologies can partially improve the ability to distinguish certain colours.

Tritanopia

Tritanopia is much less common. It is characterised by difficulty perceiving the blue and yellow parts of the spectrum.

People with this condition may confuse some shades of blue, green and purple.

This form is much rarer than red-green colour blindness.

How colour-blind people see the world

When people first learn about colour blindness, they usually want to know how colour-blind people see the world around them.

In fact, most patients still see many colours. The problem is not a complete lack of colour perception but difficulty recognising certain shades.

For example, with red-green colour blindness some objects may look almost the same colour, even though people with normal vision can easily tell them apart.

So the answer to the question of how colour-blind people see colours depends on the specific type of deficiency.

How a colour-blind person sees different colours

How a colour-blind person sees the objects around them depends on the form of the condition.

With protanopia, red shades may look darker than usual.

With deuteranopia, there are difficulties with the green part of the spectrum.

With tritanopia, it is hard to distinguish blue and yellow shades.

Some colours start to blend together, which can cause certain inconveniences in everyday life.

Which shades are difficult for colour-blind people

Colour perception depends on the specific form of colour blindness. Most often a person finds it hard to tell apart shades that look completely different to people with normal vision.

Difficulties most often arise with the following colour combinations:

• red and green;
• green and brown;
• pink and grey;
• blue and purple;
• yellow and light green.

These are the colours that colour-blind people may perceive as similar in brightness or saturation. The severity varies from person to person: some experience minor difficulties, while others can barely distinguish certain shades.

Everyday life with colour blindness

For most patients, a colour vision deficiency is not a serious obstacle in daily life. Over time, people get used to how they perceive colour and learn to rely on other cues, such as the position of objects, brightness or contrast.

However, in some situations colour blindness can cause certain inconveniences. These are most often related to:

• choosing clothes and matching colours;
• using maps, diagrams and infographics;
• identifying colour-coded wires or equipment;
• reading graphs and charts;
• judging how ripe fruit, berries and vegetables are.

Today many of these difficulties are successfully solved thanks to modern technology. There are special mobile apps, electronic assistants and digital services that quickly identify the colour of an object and help people with colour vision deficiencies handle everyday tasks with more confidence.

Colour blindness in children

Colour vision deficiency is often detected in childhood.

Parents may notice that their child:

• names colours incorrectly;
• mixes up coloured pencils;
• has difficulties in drawing lessons;
• cannot distinguish certain shades.

Early diagnosis helps avoid problems at school and helps the child adapt to their condition more quickly.

Diagnosing colour blindness

Special diagnostic methods are used to detect colour vision deficiencies.

The main method is diagnosing colour blindness with pseudoisochromatic (colour dot) plates.

During the test, the patient looks at images made up of many coloured dots. Hidden among them are numbers, lines or shapes that need to be recognised.

The results show whether there is a problem and what type it is.

Colour blindness test

A modern colour blindness test is a simple and painless procedure.

It is recommended for:

• school-age children;
• drivers;
• candidates for certain professions;
• people with suspected colour vision deficiency.

A professional colour blindness test accurately determines how a person perceives colours.

Checking yourself for colour blindness

Today many people try to check their vision for colour blindness using online services.

There are various ways to take a colour blindness test online . They help give a preliminary idea of your colour vision.

However, the results of such tests are not always accurate, as they depend on the screen quality, lighting and device settings.

So if you suspect a problem, it is recommended to have a full colour vision test with a specialist.

Colour blindness tests

The most common diagnostic tools are colour blindness tests based on the Rabkin and Ishihara plates.

With these tests, the doctor can determine whether there is a deficiency and clarify its type.

If necessary, an additional test for the type of colour blindness is performed to assess the patient's colour perception more precisely.

Can colour blindness be treated

One of the most common questions patients ask is whether colour blindness can be treated .

If the condition is inherited, modern medicine does not yet have a way to fully restore normal colour vision.

However, there are technologies that help improve the perception of certain shades:

• special glasses;
• filtering lenses;
• digital apps;
• electronic colour recognition systems.

In acquired forms, treating the underlying cause can sometimes partially restore colour vision.

Which professions have restrictions

Although colour blindness is not considered a serious disease, some professions have special colour vision requirements.

Certain restrictions may apply to:

• pilots;
• train drivers;
• sailors;
• military specialists;
• transport workers;
• certain technical professions.

This is why a colour vision test is often part of mandatory medical assessments.

Colour blindness: treatment and prevention

When it comes to the inborn form, treatment and prevention of colour blindness have their own specifics.

Inherited colour blindness cannot be fully prevented. However, acquired forms can be prevented through timely treatment of eye and nervous system diseases.

An important role is played by prevention of colour blindness , which includes:

• regular check-ups with an ophthalmologist;
• managing chronic diseases;
• protecting the eyes from injury;
• timely treatment of retinal conditions;
• monitoring the condition of the optic nerve.

Conclusion

Colour blindness is a vision trait in which the perception of certain colours and shades is impaired. The answer to how colour-blind people see and what types of colour blindness exist depends on the specific form of the condition. A modern colour blindness test and a full examination help detect colour vision features in good time. Although inborn colour blindness cannot be fully cured, modern technologies help people successfully adapt to everyday life, study and work.

To know exactly what is happening with your eyes, have a comprehensive eye examination — the doctor will check all structures of the eye and explain the results.