Colour Blindness: One In Every Classroom

I remember it well. My son was three years old and he was naming his colours in all sorts of mismatched ways. I was expecting it. Expecting that at least one of my kids would be colourblind, considering that my dad has it and it is genetic. 

When the results came back, I wasn’t surprised. What I was more surprised by was the the massive difference in which he sees the world. I made contact with an app developer, MySight, and chatted to him about this. I used his app to set up a profile for my son. I watched in amazement as he set the parameters on the app - I couldn’t believe how far along the gradient bar he scrolled until the colours looked right to him. Just watch below!

This app has been such an amazing part of my toolkit. It’s hard to understand what a colourblind person sees. As a hidden disability, it’s also very easy to forget about it in everyday life. “Go and get the green plate… it’s beside the brown box… look how blue the sky is today”. It’s everything. 


A side by side view of colouring pencils showing how a colour blind person perceives them
Side by side view of how my son sees his colouring pencils for school.

This is an incredibly important thing for teachers to be aware of. 1 in 12 boys are colourblind. 1 in 200 girls are. Worldwide, around 300 million people are colourblind. There are very high chances that someone in your class each year is colourblind. There’s also a very high chance that they don’t even have any idea that they are! Children are no longer screened for this and it is believed that around 80% of children enter secondary education undiagnosed


Red flowers vs what my son sees - a green flower.
The plants in our house hit different.

There are different kinds of colourblindness and it’s likely that people’s understanding of it is not quite as high as it could be. It does not mean that people are blind to a colour in that they can’t see it, or that they can’t see colours at all. There is also a perception that it just means they get red and green mixed up, like they don’t know the words for the colours. In reality, it is much different. It means that their perception of certain colours is skewed and it affects the whole spectrum of colours. 

My son, who's 10 now, for example has the deuteranopia version of colour vision deficiency. When I try to understand what he sees, I best describe it as ‘he sees everything in varying shades of green, a few bits of blue and he can see yellow really well’. He always says his favourite colour is yellow, which is because that is really the only colour that most definitely stands out for him. 


Side by side view of footballs through the eyes of a colour blind person
Even his passion of playing football is affected.

This has been a learning curve for me as a parent. It has been great to have my dad explain it to me, because it’s very difficult for a 10 year old to answer questions about it. The MySight app has been amazing because I can check in on him by scanning things with the app and then seeing what he sees.

So how does this affect you as a teacher?

Think carefully about how you label your new classroom this year. Do you rely solely on colour as a distinguishing feature? For example, red boxes for incomplete work, green boxes for complete. Or yellow stickers on certain trays and green on others. The best thing to do is add in another feature. So a red SPOTTY box and a green STRIPY box. When you ask children to hand in books, refer to the boxes by both features - “put your work in the red spotty box”. 

When doing PE, do you often set out cones and ask children to run to the red cone? Add numbers to each cone as well. Ask children to run to the 'red number 1 cone'. This allows children with colour vision deficiency to easily follow the instruction and not be embarrassed. This is one of his biggest embarrassments as sport is his passion and something he really excels at... but he's held back by the colours sometimes.

Label your colouring pencils and pens. Add colour names to each one to enable children to independently access them. My son tells me that he often waits until a friend has used a colour and then he immediately picks it up to colour in the same item, knowing that he’ll get it right that way. 

Do not assume that because you haven’t been told of a colourblind pupil in your class, that you have none. As I quoted above, around 80% of children are not even diagnosed by the end of primary school. Instead, assume you have one and plan your teaching around that philosophy. 

Think about the graphs or charts that you share, or spreadsheets that are colour coded. 

Think about the lessons you teach around colour, embedding those early learning skills that are so necessary. My son can only see two colours in the whole rainbow!

Do you categorise the books in your room by colour? 

Do you use different colours when writing on the board - for example, underlining nouns in red and verbs in green?

Think about how you use practical materials for pattern making or practical maths. 

How can you spot colour vision deficiency in your students?

Here’s a few ideas, but bear in mind that this will vary greatly among individuals.

  • Do they use colours inappropriately? Do you see green tree trunks or purple hair when they colour in?
  • Are they reluctant to be involved in colour sorting activities?
  • Do they copy their friends rather than work independently?
  • Do they fill in answers inappropriately?
  • Do they seem lost during PE sessions?

Once you’ve got your head around this… did you know that there are colour vision deficiency settings right on your iPad? Whoo!!

In Accessibility - Display and Text Size - Colour Filters. Switch on the colour filters and test out the settings. Ask your students if it looks better for them. There is no treatment for colour blindness. They will never see the colours that you and I take for granted. My understanding from chatting with my son is that the colour filters change the contrast, intensity and tone, which can help them distinguish between the colours more easily. Everything that can make the life of the children in your classroom easier is a win.

Finally, watch this video for a child’s eye view on colour blindness. I’d love to hear your thoughts in the comments below!


All Replies

Posted on August 06, 2023

Thank you for sharing this Karen! It is timed perfectly as one of my classes next session includes a boy who is colourblind. I remember last session having to think on my feet when l was visiting his class to deliver some coding input using Kodu. The game they were creating was based around coloured robots eating different coloured apples, colours he could not differentiate between. I had introduced the task and everyone was getting down to work, when he tapped me on the shoulder to let me know. While we came up with a solution together, it really made me look at things that I took for granted, differently. Your tips and things to think about will be so helpful in the coming weeks. Thank you!

Posted on August 07, 2023

You’re very welcome, I’m so glad it’s useful. 😀

Posted on August 09, 2023

Thank you for your post. It is a good reminder (and information) on how important accessibility tools are for teaching and learning.

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