Color Blindness FAQ: 20 Clear Answers

All 20 questions

What is color blindness?

Color blindness, also called color vision deficiency, means you see colors differently from most people and may find it hard to tell some colors apart. It usually runs in families, and most people with it manage everyday activities. According to the National Eye Institute, there is no cure for the inherited kind.

Sources: National Eye Institute: Color Blindness

Is an online color blind test accurate?

Not fully. An online test can show signs, but screens differ in brightness and color, so results vary. The NHS says tests are available online but it is important to get checked at an optician if you have concerns. Only an eye care professional can diagnose color blindness.

Sources: NHS: Colour vision deficiency

How common is color blindness?

The National Eye Institute says about 1 in 12 men have color vision deficiency. MedlinePlus Genetics reports red-green types in about 1 in 12 males and 1 in 200 females among people of Northern European ancestry, with lower rates in almost all other populations studied.

Sources: National Eye Institute: Color Blindness, MedlinePlus Genetics

What is the most common type of color blindness?

Red-green color vision deficiency is the most common kind. The National Eye Institute names deuteranomaly as the most common red-green type. It makes certain shades of green look more red, is usually mild, and does not usually get in the way of normal activities.

Sources: NEI: Types of Color Vision Deficiency

Can you become color blind later in life?

Yes. Most people are born with it, but color vision deficiency can also come from eye diseases such as glaucoma, brain and nervous system diseases, some medicines, or injuries. Color vision may also get worse with age, especially with cataracts. See an eye doctor if your color vision changes.

Sources: NEI: Causes of Color Vision Deficiency, AAO: What Is Color Blindness?

Can color blindness be cured?

There is no cure for color vision deficiency that runs in families, but most people adjust to it, say the NHS and the National Eye Institute. If another health problem or a medicine causes it, treating the condition or changing the medicine may help.

Sources: NHS: Colour vision deficiency, National Eye Institute: Color Blindness

Do color blind glasses work?

For some people with milder red-green color blindness, special glasses may improve contrast between some colors. The American Academy of Ophthalmology says results vary, the glasses do not give natural color vision, and the effect lasts only while you wear them. They do not help if red or green cones are completely missing.

Sources: AAO: Do Colorblindness Glasses Really Work?

How do I know if my child is color blind?

The NHS lists signs such as using the wrong colors when drawing, trouble sorting colors, lack of interest in coloring, and smelling food before eating it. Children may hide it. The National Eye Institute advises a test if you are concerned or if it runs in the family.

Sources: NHS: Colour vision deficiency, National Eye Institute: Color Blindness

What do I see if I have deuteranopia?

Deuteranopia makes it impossible to tell red from green at all, says the National Eye Institute. MedlinePlus Genetics describes trouble telling some shades of red, yellow and green apart. Our simulated color wheel on the types page gives an idea, but nobody sees exactly through another person’s eyes.

Sources: NEI: Types of Color Vision Deficiency, MedlinePlus Genetics

What is the difference between protan and deutan?

Both are red-green types. Protanomaly makes certain shades of red look more green and less bright, while deuteranomaly makes certain shades of green look more red. Protanopia and deuteranopia both mean no ability to tell red from green. A screen test cannot reliably tell the types apart.

Sources: NEI: Types of Color Vision Deficiency

What is tritanopia, or blue-yellow color blindness?

Tritanopia is a rare blue-yellow type. The National Eye Institute says it makes someone unable to tell blue from green, purple from red, and yellow from pink, and colors look less bright. MedlinePlus Genetics says blue-yellow defects affect fewer than 1 in 10,000 people worldwide.

Sources: NEI: Types of Color Vision Deficiency, MedlinePlus Genetics

Does color blindness get worse with age?

Inherited color vision deficiency does not get better or worse over time, says the National Eye Institute. But color vision may get worse as you get older, especially with cataracts, and diseases or medicines can change it. A noticeable change should be checked by an eye doctor.

Sources: NEI: Causes of Color Vision Deficiency, AAO: What Is Color Blindness?

Why are men more likely to be color blind?

Red-green color vision deficiency is passed on through the X chromosome. Males have one X chromosome, so one affected copy is enough. Females have two, and both must carry the gene, which rarely happens, explains the National Eye Institute. Blue-yellow color blindness involves other chromosomes and affects both sexes equally.

Sources: NEI: Causes of Color Vision Deficiency

Can women be color blind?

Yes, but it is much rarer. MedlinePlus Genetics gives about 1 in 200 females for red-green types among people of Northern European ancestry, compared with about 1 in 12 males. Blue-yellow color vision deficiency affects males and females equally.

Sources: MedlinePlus Genetics

Does color blindness affect how sharp my vision is?

Usually not. MedlinePlus Genetics says red-green and blue-yellow defects do not affect sharpness of vision, and the American Academy of Ophthalmology says sharpness is unaffected except in the most severe form. Complete color blindness can come with poor vision, light sensitivity and involuntary eye movements.

Sources: MedlinePlus Genetics, AAO: What Is Color Blindness?

Can color blindness affect jobs?

It can. The NHS says it may mean you cannot do certain careers for safety reasons, such as being a pilot or train driver. The National Eye Institute adds that adults may need accommodations for jobs that depend on telling colors apart, such as graphic design. Requirements vary, so ask the employer or an eye doctor.

Sources: NHS: Colour vision deficiency, National Eye Institute: Color Blindness

What is total color blindness?

Complete color vision deficiency, also called monochromacy or achromatopsia, means not seeing colors at all. The National Eye Institute calls it rare, and depending on the type there may also be trouble seeing clearly and more sensitivity to light. Blue cone monochromacy affects about 1 in 100,000 people, says MedlinePlus Genetics.

Sources: NEI: Types of Color Vision Deficiency, MedlinePlus Genetics

What is the Ishihara test, and is this the same?

The NHS describes the Ishihara test as reading images made of colored dots. It is one of two main tests for color vision deficiency; the other has you put colored objects in order. Our test also uses dot plates, but every plate is drawn by our own code and none is copied from Ishihara.

Sources: NHS: Colour vision deficiency

Should I see an eye doctor if I fail an online test?

Yes, if you have concerns. The NHS says to go to an optician if you or your child have signs of color vision deficiency, and notes that color vision testing is not part of the routine NHS eye test, so you need to ask for it. A screen test is not a diagnosis.

Sources: NHS: Colour vision deficiency

Can medicines or health conditions change color vision?

Yes. The National Eye Institute lists eye diseases such as glaucoma and macular degeneration, conditions such as Alzheimer’s disease and multiple sclerosis, some medicines such as Plaquenil, and eye or brain injuries. The American Academy of Ophthalmology says anyone with a significant change in color perception should see an ophthalmologist.

Sources: NEI: Causes of Color Vision Deficiency, AAO: What Is Color Blindness?