What is colour vision deficiency (colour blindness)?

FG Contacts Feel Good Team
Thursday, 28 May 2020 Share this blog: Facebook Twitter LinkedIn Copy link Copy Link

We explain the different forms of color blindness, as well as the new and emerging treatments to manage the condition.

What is colour blindness?

Those with color vision deficiency (CVD) cannot perceive colours in the way most people do. Our eyes use three types of cone cells affected by light sensitivity, these cells help us to recognise colour. When people cannot see colours accurately it is because they are missing one of these cone cells. The missing cone cell results in an inability to see a section of the light spectrum, affecting color perception.

Perceiving colours incorrectly can impact daily life in many ways, from not being able to tell if your banana is ripe, to not seeing that your skin is sunburnt. Traffic lights are not usually a problem because although the red light and green light may not be visible, the brightness of the light can be a guide, along with common knowledge that red is at the top, amber is in the middle and green is at the bottom.


What are the three types of colour blindness?

There are three types of color blindness, these include:

  • Tritanopia is when people have trouble seeing the difference between blue and yellow.
  • Protanopia is when people have trouble seeing the difference between red and green.
  • Monochromacy or achromatopsia is when people cannot perceive any colours. People with this condition see the world in black and white.


What is it like to have colour blindness?

People experience colour deficiency in varying levels of severity. Some people can see colours fairly well as long as they are well lit, and struggle to see colours in darker surroundings. Some people have difficulty distinguishing between colours in good or bad light. A small number of people cannot perceive colours at all and see the world in a grey tint, but they are rare cases.


three circles containing coloured numbers designed to test for colour blindness

How common is colour blindness?

Colour blindness affects 1 in 12 men and 1 in 200 women worldwide. In Britain alone, there are 3 million people who have colour vision deficiency with the majority being male.


Is colour blindness genetic?

Colour blindness is largely hereditary, however, it can also develop from illness, medication, eye-related accidents and eye conditions such as age related macular degeneration. The condition is passed from parent to child via the X chromosome, which is why it largely affects men much more so than women.


A deficiency in seeing colours can be experienced later in life, however, once experienced the severity of the blindness usually remains the same. If you are colour blind and notice a change in the way you perceive colours, contact your optician.


Is there a cure for colour blindness?

Currently, there is no cure for colour blindness. There is, however, emerging evidence to show dyed contact lenses could help with symptoms of colour vision deficiency. Researchers at the University of Birmingham have developed a dyed contact lens that could help people see colours more efficiently. The people who tested these dyed lenses reported an improved ability to distinguish between colours.


The dye is completely safe to use and is also inexpensive. The dye could also be used in contact lenses as well as glasses. Although there are already sunglasses to help with colour perception.

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