How to identify colour-blind pupils in your school

Kathryn Albany-Ward

Following a career in retail property development, Kathryn Albany-Ward founded the Colour Blind Awareness Organisation in 2009 after her son was diagnosed with deuteranopia. She was dismayed to discover that there was no formal advice available to support her son and the 400,000 other colour-blind schoolchildren in the UK. Having successfully launched the www.colourblindawareness.org website, she now promotes the interests of colour-blind people everywhere by providing training to schools, advising businesses in how to become colour-blind compliant and giving interviews and providing advice to the BBC and others for TV, radio and website articles.

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Did you know there is probably one colour-blind child in every class in your school, or that you may have had a colour-blind child in every class you have ever taught? Surprised?

We probably all know colour-blind people, they might be friends or family members; fathers, husbands or sons. You might even be a colour-blind teacher yourself. Everyone knows colour-blind people sometimes wear strange colour combinations, and we all appreciate that they confuse reds and greens, but how many of us have ever stopped to think ‘how is it possible to confuse red with green?’

We might have had the odd laugh at the expense of a colour-blind friend, but for colour-blind children (and teachers) in school today, their condition is no laughing matter. One of the very first things we teach young children are the colours of the world around them. They learn that grass is green and the sky is blue, but what if the colours we see and describe aren’t the same for the all of children we are teaching?


Colour blindness affects 1 in 12 boys (8%) and 1 in 200 girls. There are approximately 3 million colour-blind people in the UK, and 400,000 are school children – that’s one in every classroom!


Normal colour vision / Deuteranopia


What is colour blindness?


Colour blindness is (usually) an inherited condition affecting ability to perceive colours, caused by ‘faulty’ gene-sequencing in the DNA of the X-chromosome.


We have 3 types of cone cells in the retinas of our eyes. Each type is responsible for detecting either red (protan), green (deutan) or blue (tritan) light. In colour blindness (colour vision deficiency, or CVD), the faulty sequencing results in one type of cone cell being unable to recognise which wavelength of light it is receiving. Consequently, the brain receives incorrect information and can’t properly interpret colour, so someone with CVD is not able to distinguish between colours normally.


The X-chromosome is also the sex chromosome. Women have two X-chromosomes and men have an X-chromosome and a Y-chromosome, hence CVD is much more common in boys / men than women.


There are rare forms of colour vision deficiency - blue blindness and monochromacy, but red and green colour deficiency is very common. Colour blindness can also be acquired as a side effect of some diseases, e.g. diabetes.


What Do Colour-Blind People See?


Normal colour vision / Protanopia


Colour-blind people can see clearly and in-focus, and it is important to remember that to them what they see is normal, consequently they often reach adulthood without realising they have a CVD.


People with CVD commonly experience problems with reds, greens, browns, oranges and yellows because all of these colours appear as varying shades of ‘muddy’ green. Blue and yellow can be seen but can still be confused. Blue is frequently mistaken for purple. Why? Purple contains an element of red which colour-blind people don’t see, so purple is just dark blue to them. Pastel colours generally all appear ‘grey.’ Green deficients can mistake green for greys or even pinks whereas red deficients will confuse reds with black!


Why colour matters in school


For colour-normal students and teachers, colour can be a useful tool, but for colour-blind students it can be a nightmare – undermining confidence and their ability to learn, encouraging basic errors in the simplest work, making them slower to follow instructions, causing frustration and even anger.


When children start school we ask them to pick up the red brick and describe the big brown dog. We ask them to fill in colouring sheets and sing songs about the colours of the rainbow. If children don’t understand some of what we are saying, they cannot learn to full capacity. This is a problem that can not only undermine their confidence, but provide a faulty foundation for future learning.


As pupils progress through school they are encouraged to interpret coloured maps and graphs; colour is used to highlight information on whiteboards; it is used in the science lab, the art room, in Mathematics, Food Technology, IT, Economics, Business Studies and even in languages, History and English. In sport, colour-blind players might pass a ball to the opposition because they mistake the colour of the team strip or ‘lose’ balls in the grass.


Have you ever seen a little boy competing in your Sports Day obstacle race, for no apparent reason run straight past a beanbag and wondered why on earth he did that? Well now you know!


While colour-blind children can learn to identify colours through their hue and saturation, they still cannot actually see what everyone else sees. A colour-blind pupil entering school in Reception must learn what they are told is the colour of each everyday object they come across, and try to memorise it. They are likely to focus on this ahead of other learning to ensure they don’t embarrass themselves in front of their new classmates.


So CVD students are at a clear disadvantage when compared to their colour-normal peers who instantly and automatically know the colour of objects. CVD students are also often discriminated against in class and exam situations.


How to spot a colour-blind student


Whilst every teacher will want to identify and support their colour-blind students, they are thwarted. This is because they won’t have had any training in CVD, are provided with no official information or advice (because, perplexingly, CVD is not considered a SEN), Local Education Authorities have phased out colour vision screening at school entry and colour vision testing does not form part of the NHS eye test for children. All of this results in approximately 80% of CVD students being undiagnosed when they enter secondary school.


Can you identify which child was the colour-blind student in your classes last year? Proper identification could help you achieve better results from your students. Might it even go some way to explain the 20% gender gap?


Luckily, there are some classic signs to help you spot your colour-blind students.


Key Stage 1


Inappropriate use of colour – commonly purple skies, yellow/green/grey faces, red leaves, brown grass etc.

  • Reluctance to help when tidying up if boxes are colour coded.
  • Disruptive behaviour, unwillingness/inability to play board games, matching games, some memory games, sequencing, games in PE.
  • Copying other children in colour situations where the child might consistently hold back and watch, so he can borrow a colour from a friend routinely after the friend has used it, then copy exactly where that colour went.


Key Stage 2 and above


CVD students can sometimes appear slow, distracted or disruptive – this may be because they need extra time to process information, and can result in them missing some teaching points because they are still trying to understand the previous one. Also look out for:

  • Inappropriate colour choices when completing worksheets, drawings and diagrams.
  • Presentation of work which seems ‘boring’ and lacking in colour formatting.
  • Unexpected poor results from students when using Web-based homework programmes – MyMaths, BBC Bitesize etc.
  • Holding back in sports e.g. when (i) team colours clash (ii) balls, beanbags, training cones, sports hall line markings etc. ‘disappear’ against their background.
  • Reluctance to speak in discussions where colour is a main element e.g. maps in Geography, colour propaganda in History etc.
  • Holding back in (i) Science - chemistry practicals, diagrams/microscope work, light spectrum projects and (ii) in Maths/Economics/Business Studies/Geography due to difficulty interpreting information in coloured pie/bar/line graphs.
  • Mistakes in use of colour names in language lessons.


If you think a pupil might be colour-blind, refer parents to an optician for a colour vision test.


How to improve your classroom

  • Label all drawing/art materials - felt tips, paints, pencils etc.
  • Use secondary labels on colour-code boxes of toys, art materials, beads, books.
  • Check computer-based teaching aids, web pages, computer settings, worksheets and textbooks.
  • Use secondary indicators e.g. labels, outlining, underlining, cross-hatching, to differentiate, rather than or in addition to colour.
  • Use strong contrast on whiteboards – avoiding red, green and pastel highlighting, 
  • Avoid marking in red and green.
  • Avoid ‘traffic light’ systems without secondary indicators. 
  • In sports and games ensure students can differentiate (i) teams and (ii) equipment against background.
  • Organise ‘buddies’ for science experiments, art and DT projects etc.
  • Check classroom equipment - on/off switches, charged/charging indicators etc.
  • Remember a CVD student may be entitled to a colour ‘reader’ for some external exams


Whatever their age, don’t expect colour-blind pupils to speak up! Would you? Colour-blind teachers themselves often don’t speak out when they can’t access information in school e.g. student tracking charts. Look out for the forthcoming article on colour-blind teachers.


What has your experience been with colour-blind pupils? Let us know in the comments.

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