What Is Color Blindness? Symptoms, Types, Diagnosis and Management

Created: 13.12.2024 · Last Updated: 10.08.2026 · Category: Ophthalmology · Prepared by the Academic Hospital Web and Editorial Board.

Color blindness, more accurately described as color vision deficiency, means that a person sees certain colors differently from most people or has difficulty distinguishing between specific colors and shades.

The most common form affects red-green color discrimination. Blue-yellow deficiencies are less common, while complete loss of color perception is rare.

What Is Color Blindness?

Normal color vision depends on cone photoreceptor cells in the retina that respond to different wavelengths of light. Information from these cells travels through the visual pathways to the brain, where color perception is formed.

In color vision deficiency, certain cone photopigments may function differently or may be absent. As a result, some colors may appear more similar to each other, different shades may be difficult to distinguish or colors may appear less bright.

Although the term “color blindness” is widely used, most people with color vision deficiency do not see the world only in black and white. Complete absence of color perception is very rare.

Important Information: Mild color vision deficiency may remain unnoticed for many years. It may first become apparent at school, during an occupational assessment or as part of an eye examination.

What Are the Symptoms of Color Vision Deficiency?

Symptoms depend on the type and severity of the deficiency. The main feature is difficulty distinguishing particular colors or shades that appear different to most people.

  • Confusing certain shades of red and green
  • Difficulty distinguishing some shades of blue, green, yellow or red
  • Difficulty arranging similar colors by shade
  • Perceiving the brightness or intensity of some colors differently
  • Difficulty interpreting color-coded graphs, maps, charts or educational materials
  • Frequently misidentifying the colors of clothing or other objects

People with mild inherited color vision deficiency may not realize that their vision differs from other people's because they have perceived colors in the same way since childhood.

Rare and severe forms of color vision deficiency may also be associated with reduced visual acuity, sensitivity to light or involuntary eye movements.

An eye examination may be appropriate if you have difficulty distinguishing colors or notice a new change in your color perception.

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Types of Color Vision Deficiency

Color vision deficiencies can be classified according to the color system affected and the degree of impairment.

Red-Green Color Vision Deficiency

This is the most common group of inherited color vision deficiencies. The ability to distinguish red and green shades may be affected to different degrees.

  • Deuteranomaly: One of the most common forms. Certain shades of green may appear more red.
  • Deuteranopia: Red-green discrimination is more significantly affected because of impaired function of the green-sensitive cone system.
  • Protanomaly: Some shades of red may appear greener and less bright.
  • Protanopia: Marked impairment of the red-sensitive cone system can make red-green discrimination significantly more difficult.

Blue-Yellow Color Vision Deficiency

Blue-yellow deficiencies are much less common than red-green deficiencies.

  • Tritanomaly: It may be difficult to distinguish blue from green and yellow from red in certain shades.
  • Tritanopia: Difficulty may occur when distinguishing blue from green, purple from red and yellow from pink.

Complete Color Vision Deficiency

Monochromacy or achromatopsia is rare. Color perception may be severely reduced or absent. Depending on the condition, reduced visual acuity and sensitivity to light may also occur.

What Causes Color Vision Deficiency?

Color vision deficiency may be inherited or may develop later because of conditions affecting the eye, optic nerve or nervous system.

Inherited Color Vision Deficiency

The most common red-green color vision deficiencies are usually inherited through the X chromosome. For this reason, inherited red-green color vision deficiency is much more common in males than in females.

Inherited color vision deficiency is generally present from childhood, tends to affect both eyes similarly and usually remains relatively stable over time.

Acquired Color Vision Deficiency

A change in color perception that develops later in life can be associated with several conditions, including:

  • Eye diseases such as glaucoma
  • Age-related macular degeneration
  • Cataracts
  • Conditions affecting the retina or optic nerve
  • Certain systemic diseases, including diabetes
  • Neurological conditions such as multiple sclerosis
  • Eye or brain injuries
  • Side effects of certain medications

When color vision changes after previously being normal, identifying the underlying cause is important and an ophthalmological assessment is recommended.

How Is Color Vision Deficiency Noticed?

People born with color vision deficiency may not realize that their perception is different because they have always seen colors in the same way. Mild cases may therefore remain undiagnosed until school age or adulthood.

Possible signs in children include:

  • Consistently confusing the same colors while learning color names
  • Using unexpected colors while drawing or painting
  • Difficulty sorting objects by color
  • Difficulty working with color-coded classroom materials
  • A family history of color vision deficiency
Early recognition can help at school: Color vision deficiency does not mean that a child has reduced intelligence or learning ability. However, color-coded educational material may create unnecessary difficulties if teachers and parents are unaware of the condition.

How Is Color Vision Deficiency Diagnosed?

Assessment includes the person's history, whether the change has been present since childhood or developed later, and a comprehensive eye examination when appropriate.

Ishihara Test

Ishihara color plates are among the most commonly used tests for screening red-green color vision deficiencies. The plates contain many colored dots arranged to form numbers, lines or other shapes.

A person with normal color vision and a person with red-green color vision deficiency may see different figures on the same plate, or the person with a deficiency may be unable to identify a particular figure.

The Ishihara test does not assess every type of color vision deficiency. It is primarily used to screen red-green deficiencies. Other tests may be required when a broader assessment is needed.

Color Arrangement Tests

Tests such as the Farnsworth D-15 or Farnsworth-Munsell 100 Hue test ask the patient to arrange similar colors in sequence. These tests can provide more detailed information about the type and degree of color discrimination difficulty.

Additional Color Vision Testing

More specialized methods, such as an anomaloscope, may be used in selected situations. When an acquired color vision problem is suspected, the ophthalmologist may perform additional examinations to investigate conditions affecting the retina, optic nerve or other parts of the visual system.

Can Color Blindness Be Treated?

There is currently no standard treatment that permanently restores normal color vision in common inherited color vision deficiency. Most people adapt well over time and can carry out everyday activities without major limitations.

For acquired color vision deficiency, management depends on the underlying cause. Treating an eye or medical condition responsible for the change, or medically adjusting a causative medication when appropriate, may improve color perception in some patients.

Do Color-Correcting Glasses Work?

Some specially filtered eyeglasses or contact lenses may increase contrast between particular colors and make certain color differences easier to identify for some people.

However, these devices do not restore normal color vision and do not cure inherited color vision deficiency. Their benefit varies according to the individual and the type of deficiency.

Living With Color Vision Deficiency

Most people with color vision deficiency adapt well. Difficulties are more likely when color is used as the only way of communicating information.

  • Use labels, symbols, patterns or written information in addition to color coding
  • Use smartphone or tablet applications that can identify colors
  • Label frequently used clothing or objects when necessary
  • Inform teachers when a child has color vision deficiency
  • Check specific visual requirements before choosing occupations in which accurate color discrimination is essential

People often use other visual information such as position, brightness, shape and symbols in addition to color to complete everyday tasks successfully.

When Should You See an Eye Doctor?

Inherited color vision deficiency is usually stable. Ophthalmological evaluation is particularly important when:

  • Difficulty distinguishing colors develops later in life
  • Color perception progressively becomes worse
  • Color perception differs between the two eyes
  • Changes in color vision are accompanied by reduced vision or other eye symptoms
  • A child repeatedly has difficulty learning colors or using color-coded educational material
  • Formal color vision assessment is required for occupational or other purposes

Do Not Ignore New Changes in Color Perception

Color vision tests can help determine the type of deficiency, while newly developed changes in color perception may require evaluation for an underlying eye condition.

Frequently Asked Questions

What is color blindness?
Color blindness, or color vision deficiency, means seeing some colors differently from most people or having difficulty distinguishing between certain colors and shades. Most people with color vision deficiency do not see only in black and white.
Is color blindness inherited?
Most common red-green color vision deficiencies are inherited through the X chromosome. This is why inherited red-green color vision deficiency is much more common in males.
Can color vision deficiency develop later in life?
Yes. Certain eye diseases, conditions affecting the optic nerve or nervous system, eye or brain injuries and some medications can cause acquired color vision deficiency. A new change in color perception should be evaluated by an eye doctor.
Does the Ishihara test diagnose color blindness?
The Ishihara test is widely used to screen primarily for red-green color vision deficiencies. Because it does not assess every type of color vision deficiency, color arrangement tests or other methods may be used when necessary.
Can color-correcting glasses cure color blindness?
Specially filtered glasses may increase contrast between particular colors and make some color differences easier to identify. They do not restore normal color vision and do not cure inherited color vision deficiency.
How can color vision deficiency be noticed in children?
Repeatedly confusing the same colors, difficulty sorting objects by color or problems with color-coded educational material may suggest color vision deficiency. Diagnosis is made using appropriate color vision tests.
Academic Hospital note: Evaluation of color vision deficiency should consider whether the problem has been present since childhood or developed later, whether one or both eyes are affected, medications and accompanying eye conditions. You can book an appointment for an eye examination and appropriate color vision testing.

References

  1. Academic Hospital. Renk Körlüğü Nedir? Belirtileri ve Türleri Nelerdir? Nasıl Fark Edilir?
  2. National Eye Institute (NEI). Color Blindness
  3. National Eye Institute (NEI). Types of Color Vision Deficiency
  4. National Eye Institute (NEI). Causes of Color Vision Deficiency
  5. NHS. Colour Vision Deficiency (Colour Blindness)
  6. American Academy of Ophthalmology – EyeWiki. Color Vision