What is colour blindness?

Colour blindness, a common vision condition, affects how an individual perceives colour. Contrary to its name, it doesn’t necessarily mean seeing the world in black and white. Let’s delve into the nuances of this intriguing condition.

colour blindness

1. What is Colour Blindness?

Colour blindness, or colour vision deficiency (CVD), is the inability or decreased ability to see colour or discern colour differences under normal lighting conditions. It arises from a deficiency or absence of colour-sensitive cells (cones) in the retina, the layer of the eye that captures light.

2. Types of CVD

  • Red-Green: The most common type, where individuals have difficulty distinguishing between red and green hues.
  • Blue-Yellow: Less common, involving difficulty in differentiating between blue and green, and yellow and red.
  • Complete Colour Blindness (Monochromacy): Rare, where individuals see only shades of gray.

3. Causes of CVD

  • Genetics: Most cases are inherited, caused by gene mutations on the X-chromosome.
  • Disease: Certain conditions like diabetes and multiple sclerosis can affect vision, including colour perception.
  • Ageing: The lens can yellow with age, affecting colour perception.
  • Medications: Some medications can alter colour vision.

4. Diagnosis and Impact

  • Testing: Colour blindness is usually diagnosed through comprehensive eye exams, including specialized tests like the Ishihara Colour Test.
  • Daily Life Challenges: It can affect everyday activities, like matching clothes, cooking (identifying ripeness of fruits), or interpreting traffic lights. However, most people adapt to these challenges.

5. Treatment and Management

There’s no cure for inherited colour blindness. However, special contact lenses and glasses can help some individuals distinguish between certain colours. Digital applications and tools also offer assistance in differentiating colours.


Colour blindness is a relatively common condition that affects how individuals perceive the world. While it presents certain challenges, with the right tools and adaptations, those affected can lead a normal, vibrant life. Understanding colour blindness fosters empathy and awareness, allowing us to better support those who experience the world differently.


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