What is Colour Blindness? Symptoms, Types & Causes

Ankul Tiwari
Updated: May 27, 2026
7 min read
General

Have you ever heard about colour blindness? Do you know “What is colour blindness?” Have you ever made any mistakes in identifying colour? If yes, then you are not alone. Some people face problems in differentiating the colours of traffic lights. Colour blindness generally affects our ability to identify colours such as red, green and yellow.

In this article, you are going to learn what colour blindness is, its causes, types, and whether it can be cured or not.

What is Colour Blindness?

Colour Blindness or Colour Vision Deficiency is a condition where an individual sees colours differently compared to normal vision, or sometimes fails to see any colours at all. Our eyes have special light-sensitive cells named Cones, located specifically in the Retina. Colours can be categorised into 3 types: Red, Green, and Blue. These colours respond to different wavelengths of light. The brain receives inputs from all three to form colour vision.

Types of Colour Blindness

Here are the 3 types of colour blindness found in people worldwide:

  • Red- Green Colour Blindness: The most common form, affecting roughly 8% of men and 0.5% of women of Northern European descent. Includes Deuteranopia/ Deuteranomaly (green deficiency) and Protanopia/Protanomaly (red deficiency).

  • Blue- Yellow Colour Blindness (Tritanopia): It is much rarer, affecting fewer than 1 in 10,000 people. Caused by a deficient blue cone.

  • Achromatopsia: Complete colour blindness, extremely rare. Vision is essentially greyscale.

Causes of Colour Blindness

Colour blindness occurs when the colour-detecting cells in the eyes don’t work normally. It can be caused by genetic cells. The genes are responsible for the red and green photopigments situated on the X chromosome.

Colour blindness can also develop later in life due to Glaucoma, Macular Degeneration, Diabetes, or as a side effect of certain medications, which damage the cones or the optic nerve pathways to the brain. Colour blindness in Biology is a condition where a person cannot see certain colours properly or sees them differently from most people.

How Normal Colour Vision Works

Your eyes have special cells in the retina called cones that detect colour. There are three types:

  • Blue Cones: detect blue light.

  • Green Cones: detect green light.

  • Red Cones: detect red light.

Your brain mixes signals from all three to let you see all colours.

What Goes Wrong in Colour Blindness

One or more cone types are either missing or not working properly, so the brain doesn't get the full colour information.

Type

What Happens

Red-Green

Can't tell red and green apart (most common)

Blue-Yellow

Can't tell blue and yellow apart (rare)

Total

Can't see any colour at all (very rare)

Why It Runs in Families

The genes responsible for red and green cones are on the X chromosome. Since men have only one X chromosome, one faulty gene is enough to cause colour blindness. Women have two X chromosomes, so they need both to be faulty, making it much rarer in women.

  • Men Affected: ~8%

  • Women Affected: ~0.5%

Is colour Blindness Dominant or Recessive

Colour blindness is generally recessive, but it depends on the type. Red-Green colour blindness is the most common form. It is carried on the X chromosome and is recessive. Men have only one X chromosome, so one faulty copy is enough to make them colour blind. Women have two X chromosomes, so they need both copies to be faulty. If a woman has only one fault, she will not be colour blind but can pass it on to her children. 

Blue- yellow colour blindness is caused by a dominant gene, meaning only one faulty copy is needed to cause it. It affects men and women equally.

Can Colour Blindness Be Cured?

Colour blindness cannot be fully cured right now. For most people, colour blindness is inherited from birth. No surgery or medicine can fix the damaged or missing cone cells in the eyes. The condition stays with a person for life. Some things can help make life easier. Special tinted glasses and contact lenses make it easier to tell colours apart. They don’t give normal colour vision, but they do help.

Conclusion 

Understanding “ What is colour blindness?” Helps to know how people face difficulty in seeing colour? In this blog, we learned about how our eyes work and how it helps to identify different colours in daily life. We also discussed what are the reasons behind colour blindness in an individual. Learn more interesting facts with SkillSnap Learning. Know the reason behind everything by following our blog page. Also, check our online courses for CBSE classes 6 to 10 students.

FAQ’s

Colour blindness is a condition where a person cannot see certain colours properly. It is mostly inherited and is more common in men than in women.

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