Insights into the impact of colour vision deficiency on classroom learning, from Caroline Sawyer and Caroline Atkin.
“Although I don’t have a physical condition that people can see, I do feel different to my friends because of a physical condition that you can’t see. I am colour blind.” These are the words of 9-year-old, Malachi, written for a school blog, sharing his experience of being colour blind. We can all say that we feel different in some way and the uniqueness of every human being should be celebrated.

These words shared by Malachi were a cry from the heart, wanting people to understand what is means to be colour blind, and the challenges he faces because of it, especially in the classroom.

Although Malachi identifies that his colour blindness makes him feel different, he is far from being alone. Statistically, it affects 1 in 12 boys and 1 in 200 girls – that’s one child in the average co-educational classroom. 1

What is colour blindness?

Colour blindness, also known as Colour Vision Deficiency (CVD) does not mean that you are blind to colour completely (although an incredibly rare condition called ‘achromatopsia’ does exist and was famously written about by neurologist Oliver Sacks in his book ‘The Island of the colour-blind.’) 2 As Malachi would say, you see colour ‘differently’. For someone who is red-green colour blind, it is not simply red and green they have difficulty differentiating, but any colour with red or green in – oranges, browns, blue and purple.

Colour wheel

Colour wheel for someone who is red-green colour blind

Colour wheel for someone who is red-green colour blind

An estimated 450,000 school students in the UK have have varying extents and types of CVD that fall broadly into three categories:

  • Protanomaly (reduced sensitivity to red)
  • Deuteranomaly (reduced sensitivity to green)
  • Tritanomaly (reduced sensitivity to blue) 1

All are caused by a fault in the cone cells on the retina (the back of the eye). It is usually located and passed down genetically via the X chromosome, although it can also be acquired through a traumatic brain injury. With CVD affecting such a large number of people, it is surprising that children in England are no longer routinely screened. The programme was cancelled in 2009, resulting in a hidden student population with reduced sensitivities to colour but completely unaware that their perception is different to their peers. This potentially leaves many confused at why they may misunderstand some instructions or activities when they are presented using a colour-based system.

Copious amounts of colour

Caroline Sawyer describes how her family found out that Malachi was colour blind when he was 4 years old.

“It was just before he started primary school. We had thought for a while that he had difficulty with colours and because my dad was colour blind there was a chance that he could be, and we had this confirmed at our opticians. Despite my dad being colourblind, I had never given much thought to how it can affect day-to-day activities until I investigated it some more because of Malachi’s diagnosis. The more I read, the more I understood the challenges– and particularly how it could affect him in an education system saturated in colour.

“I remember being very mindful of him starting school and that the first three topics were Autumn, followed by fireworks, then Christmas, which all relied heavily on colour. The difficulties Malachi faced were highlighted during lockdown online learning, where information was presented in such a way that he couldn’t do it independently because of the use of colour – maths lessons were particularly a problem.”

Imagine being colour blind and told to underline something in red; to make a colour pattern with some counters; to say what percentage of a pie chart is represented by a particular colour; to pass a ball to someone on the other team wearing a coloured bib that you can’t differentiate from yours – together with a long list of other colour tasks pupils are asked to do on a daily basis.

Challenging assumptions of accessibility

Teachers often use colour to make information clearer, create opportunities for dual coding or help learners make links between new pieces of information, but as Teacher and Researcher Caroline Atkins explains, these things can still be achieved for all pupils with awareness and a critical eye:

“The problem most teachers have is that we often don’t know which pupils in our class have CVD. The best approach would be to review resources for all colour indicators and to add a secondary label onto diagrams. For example, a lot of schools use a red, amber, green traffic light system which is inaccessible for some pupils. These systems can still be used with the addition of labels with colour words or letters on.

“The same applies to marking policies, a lot of teachers are restricted in which colours they can use to mark in, with students expected to respond in a different colour. If this marking is done over a set of writing it is very difficult to pick out. Adding an indictor in the margin or placing the marking on a separate part of the page is a huge help to the learners, whether they are aware of their CVD status or not.

“We cover the structure of the eye and the perception of colour explicitly in our Science curriculum, and we’ve found that through our discussions with pupils about CVD, some have realised this is the reason they have been having difficulties in school. I strongly urge parents to request a test with an optician, and then let the school know the results so that teachers can start to be more aware of their colour choices.”

Championing CVD needs

Caroline Sawyer did just this. “I am very grateful to Colour Blind Awareness who champion the needs of the colour blind. I shared the information they have on their website with Malachi’s school, to help create a Special Educational Needs Plan right at the start of his education, which his new school adopted and reviewed over time.” The website has a wealth of resources and advice for parents and teachers, e.g., providing labelled pens and paints and ensuring that the classroom has good natural lighting.

There are simulation apps that can show what an image would look like to the different types of CVD. Whilst not completely accurate for every person’s perception, it can help teachers to check their resources or activities and adapt accordingly.

Example of simulation app showing how someone with CVD could see the colouring pencils. Top image 'normal' colour vision, bottom image 'red-blind (protanopia)' vision.

Top image 'normal' colour vision, bottom image 'red-blind (protanopia)' vision.

Connecting case by case

However, with the type and extent of CVD varying between cases, the best source of advice is often from the pupils. During lockdown in January 2021, after reading a class book called ‘Wonder’ by RJ Palacio, Malachi was inspired to learn more about colour blindness. He identified with the main character in the story who has a physical condition which makes him look different. The thoughts and feelings addressed in this book led him to write about how colour blindness affects him, and the ways people can support him, especially in the classroom. His teacher and headteacher were so impressed with what he had written that it was made into a book called ‘Colour Blindness and Me’.

In his book, Malachi says that there have been times when he has “felt confused, left out, afraid to speak up, cross and frustrated because of the way colour has been used.”3 He simply wants people to understand, be kind and take note of the voices of those who are colour blind and the people and organisations who advocate for them, so that teaching practices can be more inclusive.

A tiny bit of awareness can make a huge difference to that one student in every classroom.


  1. Albany-Ward, K. (2018, November). Teaching children with a colour vision deficiency (colour blindness). Retrieved from Colour Blind Awareness:
  2. Sacks, O. (1996). The Island of the Colour-blind. London: Picador
  3. Sawyer, M. (2021) Colour blindness and me. UK: Sawyerbeane Publishing.



  • Caroline Atkins

    Caroline is a Secondary Science Teacher who works with STEM outreach organisations to develop public engagement resources and events. She is currently researching Colour Vision Deficiency (CVD) and Education as part of the MRes/EdD at the University of Brighton
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  • Caroline Sawyer

    Caroline is a mum of three children and the Publisher of her son's book, ‘Colour blindness and me.’ She is enthusiastic about helping to raise awareness in schools of the needs of those who are colour blind and to help her son's voice be heard. She volunteers in a local primary school and is a trained Forest School Practitioner.
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