What is colour blindness or Colour Vision Deficiency (CVD)?
Colour blindness, or colour vision deficiency (CVD) is a condition in which certain colours cannot be distinguished. There’s no treatment for CVD.
It’s most commonly due to an inherited condition.
Forms of CVD include:
- red and green CVD – by far the most common form, about 99%, it causes problems in distinguishing reds and greens
- blue and yellow CVD, which is rare
- total CVD – seeing in only shades of grey, which is extremely rare
Education strategies that can help
- Teach CVD children the ‘correct’ colours for everyday items so that they know that, say, strawberries, are red, even though they ‘see’ them as, for example, murky green. CVD children can learn to identify many, but not all, colours by identifying through shade.
- Colouring pencils with the name of the colours written on the side
- If using coloured counters etc to help with say, maths, check the CVD child can differentiate the colours used. Many teaching aids are in primary colours but a colour blind child will ‘see’ red and green as the same colour. Board games usually cause problems
- On a map, features can be distinguished by photocopying the map in colour and marking the features in black or using a strong primary colour to show the focus area
- Whiteboard to have strong contrast. Use black font as opposed to yellows, reds, and so on
- Use shading in graphs, charts, and whiteboards instead of requiring the student to see colour
- Label items that require colour recognition
- Avoid ‘traffic light’ systems for the child to indicate how difficult he thinks his task is or for next steps.
- Maximise colour contrast where possible, for example wall display background with the colour of the pages the children have done their work on
- In early years for matching activities, perhaps use different textures to start
- In science CVD children might not be able to read litmus paper, carry out chemical titrations, identify a material by its colour when burnt, understand colour diagrams in biology textbooks, etc so be mindful of the issues when setting practical tests.
- For older students consider colour in textbooks and provide modifications
- In art organise a colour palette for the student to memorise colour placement and offer other mediums other such as textiles etc
- Food technology students may not be able to be able to see if e.g. meat properly cooked, distinguish between ripe and unripe fruit or use colourings and decorations correctly.
- Lighting is important. Bright, low, inside or natural light can affect colour recognition. The brighter the light the easier it is to recognise colour. Think about seating position.
- PE check the child can see which children are in their team and also that they can see the ball e.g. red cricket balls and orange hockey balls are difficult to see against grass, particularly in poor light
- Make sure external examining bodies are made fully aware of the student’s colour blind condition as some questions may be inaccessible without modification.
- A colour detector can help: Talking Colour Detector | RNIB