Colour Blindness Day

Colour Blindness Awareness Day was launched in 2015 and is held on September 6th – the birthday of John Dalton. He is credited with being the first person known to realise colour blindness exists. Furthermore, he also introduced atomic theory into chemistry. As a scientist, he became aware that neither he nor his brother saw colours the same way as everyone else. He thought this was because they had blue liquid in their eyes and Dalton left his eyes to science so that research could be carried out after his death. Dalton understood that because both he and his brother were affected, their condition must be hereditary. Over 150 years later DNA proved he had inherited colour blindness. Colour blindness is also known as Daltonism in his memory.

What is Colour blindness?

We’re sure you are aware that not all disabilities are visible. Colour blindness or colour vision deficiency (CVD) is one of those that you may not realise is affecting someone. It affects roughly 1 in 12 men and 1 in 200 women. The effects can be mild, moderate or severe. You can be born with CVD, or it can start at any age. It can be a side effect of conditions such as diabetes and multiple sclerosis or as a consequence of the eye disease glaucoma. Medications or exposure to certain chemicals can also cause colour deficiencies.

Unfortunately, there is currently no known cure or treatment for inherited colour blindness. Those with the condition will find that they can adapt to it to some extent but may not be able to pursue professions where accurate colour vision is required. If a colour vision deficiency is developed because of illness, injury or medication, addressing the underlying condition may help.

The main symptom of CVD is finding it hard to tell the difference between colours. There are different types of CVD – the most common being unable to fully ‘see’ red, green or blue light. Being ‘red/green colour blind’ means people with it can easily confuse any colours which have some red or green as part of the whole colour. So someone with red/green colour blindness is likely to confuse blue and purple because they can’t ‘see’ the red element of the colour purple.


Testing for CVD

There are 2 main tests for colour vision deficiency:

  • the Ishihara test – reading images made up of coloured dots. The Ishihara test is used to detect the most common types of colour blindness, which are categorised as red-green colour deficiencies
  • colour arrangement tests – putting coloured objects in order of what shade they are


Colour vision testing is not part of the routine NHS eye test, but you can ask an optician for it if you think you need it.

Effects on daily life:

Driving – More specifically identifying signal lights and colour-coded signs that are designed to stand out such as danger and warning signs.

Colour coded charts – People suffering from colour blindness can have great difficulty reading colour-coded charts and other similar types of activities.

Jobs – Certain job restrictions apply for someone with a colour vision deficiency, such as a train driver.

Education – Not being able to distinguish colours when needed to complete taught activities and assessments.

Living a life full of colour – Something most of us take for granted but it is estimated that someone who is colour blind may only see as few as 10,000 shades of colour compared to someone with normal colour vision who can see up to 1,000,000 distinct shades of colour.

CVD is just one of many disabilities that can hinder the learning experience and make daily activities like using the web difficult or impossible. The demand and need for physical and digital accessibility will only continue to rise, underscoring the critical importance of raising overall disability awareness.

Edinburgh Napier University

Edinburgh Napier accessibility statement:

If you would like advice about how the university can support students and staff with physical disabilities and mental health issues you can contact the Napier Wellbeing, Support and Inclusion team:

Hardware available to borrow from the library

We have a range of ergonomic keyboards and mice, noise-cancelling headphones, laptop riser stands and coloured overlays available for everyone to borrow from each campus library. You can use Library Search to see what is available-it helps to select ‘Equipment’ under the Format filter options on the right-hand side.

We also have extra-large monitors and height-adjustable desks in each library, ask at the helpdesks to find out where they are situated.

Our library assistants are happy to help with all your well-being queries.

By Vivienne Hamilton

Photo by Victor Freitas on Unsplash