Colour blindness is a condition where a person cannot distinguish between different colours. It means that people are unable to see the different colours of the spectrum. Colour blindness usually runs in families and can affect individuals in various ways. For example, some people cannot distinguish between red and green, others between yellow and blue and some may not be able to see any colour at all, albeit very rarely is this the case.
Colour blindness is likely to affect your daily life especially when you are doing certain tasks like driving or reading. Since many individuals are impacted by colour blindness, there is a need for a bespoke solution to cater to every type of colour blindness. Some people with colour blindness are heavily affected and need daily aid whilst others aren’t affected at all. Therefore in this article we will explore the different types of colour blindness and the different strategies that exist to cope with the condition, which includes physical aids, mental support and tips/resources for those affected.
Understanding colour blindness
Types of colour blindness
According to the National Eye Institute, there are three types of colour blindness:2
Red-green colour blindness
Red-green colour blindness is the most common type of colour deficiency in people, and as the name suggests, it is caused by the difficulty to distinguish between the colours red and green. This deficiency can be further subclassified into three further categories:
- Deuteranomaly— The most prevalent form of colour blindness. To a person with deuteranomaly green colour appears to be redder. The good news is that deuteranomaly does not heavily impact the daily lives of people
- Protanomaly— To a person with protanomaly the colour red appears less bright and more green. A colourblind person with this condition usually exhibits mild symptoms and their daily life is not heavily impacted
- Deuteranopia and Protanopia— Here the person cannot perceive or distinguish the red and green colours from one another
Blue yellow colour blindness
Blue-yellow colour blindness is less common and the person finds it difficult to distinguish the colours blue and yellow. It can be sub-categorised into the following:
- Tritanomaly— The person usually finds it difficult to distinguish between the colours blue and green, and red and yellow
- Tritanopia— The person usually finds it difficult to distinguish between the colours blue and green, purple and red, and yellow and pink
These 2 types of colour blindness are more debilitating as they affect the ability to see other colours and not just blue and yellow.
Complete colour blindness
Complete colour blindness, also known as monochromacy, is the most debilitating form of colour blindness as the individual sees everything in black and white. A person with complete colour blindness, cannot distinguish any colours and in some cases, individuals can be more sensitive to light or have troubled vision. However, this is the rarest form of colour blindness.
Causes of colour blindness
We perceive colour through the cones located behind the eye, which are made up of nerve photoreceptor cells in the retina. The cells allow us to process images in the brain, including the different wavelengths of light where each colour is a wavelength, from 380 nm to 700 nm.1
In people with colour blindness the cones do not work efficiently. There are three types of cones located behind our eyes:
- Blue sensing also known as S cones detects short wavelengths
- Green sensing also known as M cones, detects midrange wavelengths
- Red sensing also known as L cones detects longer wavelengths
A colourblind person with protanomaly and deuteranomaly, who cannot differentiate between red and green colours, have less sensitivity in the L and M cones respectively. This is responsible for the way red and green colours are perceived by the affected people. In protanopia and deuteranopia, the ability to perceive colour is altered due to an absence of the respective L and M cones.1
Our cones are controlled by visual pigments, which are coded by opsin genes in our chromosomes. S cones are controlled by opsins located on chromosome 7 while the L and M cones are controlled by the opsin genes found on the X chromosome. For individuals assigned male at birth (AMAB) to be affected by colour blindness, they will need to carry the defective gene on their only X chromosome. On the contrary, individuals assigned female at birth (AFAB) are born with two X (XX) chromosomes and would need both of these chromosomes to be defective in order to express the condition. This explains why AMABs are more commonly affected by colour blindness than AFABs.2
How colour blindness is diagnosed?
A colour plate test is made up of an array of coloured dots with an outline of a number in the middle. The shape or number is visible only to people with normal colour vision. If it can’t be perceived, then the person has colour deficiency. There are different colour palettes that can be used to test for the degree of deficiency.
Coping strategies for colour blindness
Distinguishing colours based on brightness and saturation
A colourblind person will go through the anomaloscope test to distinguish between different brightness levels, or how they perceive bright light. A hue test allows them to differentiate between the different colours of a spectrum whilst saturation indicates the level of colour mixed with brightness. These tests help guide the patients in their daily lives such as in
the workplace, school or during driving.
Use labels and tags
Using labels like "red" and "green" instead of relying solely on colour can make it easier for individuals with colour vision deficiencies to understand and navigate through life. Additionally, using high-contrast colour combinations and avoiding relying on colour alone can further aid in accessibility
Use technology and apps
There are many different technologies that are currently available, including colour identification tools, colour blindness simulators, and customized colour palettes that can help people who suffer from colour vision impairment.
Consider special lenses and glasses
EnChroma lenses, for example, are designed to enhance colour perception for individuals with red and green colour blindness. Additionally, colour-filtering contact lenses can be used to adjust colour vision and improve the ability of the affected person to distinguish between certain colours. 4
Tips for daily life with colour blindness
In the workplace
- Request colour blindness-friendly materials for presentations, charts, or diagrams
- Utilise alternative cues such as text, symbols, or patterns to identify items or data that rely on colour differentiation
- Advocate for accessibility and educate colleagues on colour blindness
- Avoid colour-coded information
- Label colours with text
- Raise understanding about the condition
In social situations
- Educate others about the condition
- Use patterns or textures to differentiate objects
- Avoid relying on colour for communication
In daily activities
- Be mindful when driving or crossing streets
- Advocate for inclusive design
- Choose clothes with high-contrast
Coping with the emotional impact of colour blindness
Coping with frustration and disappointment
People who suffer from colour blindness can combat frustration, lack of confidence, anger.5 You can try to cope with these emotions by celebrating the unique perspective and strengths that you have, and/or engaging in activities that do not rely on colours, such as music or sports.
Seeking support and assistance
When it becomes difficult, seeking support from loved ones, friends, or mental health professionals is always readily available thus, communication is key. It is also important to learn more about colour blindness to understand and accept it.
Resources for coping with colour blindness
Organizations and support groups
- The Color Blind Awareness organization
- The International Association of Accessibility Professionals
- The National Eye Institute
Assistive technology and products
As mentioned, there are a few ways to cope with this condition when it becomes debilitating. Here is a summary of helpful products that can assist people with colour blindness:
- Colour filter glasses or contact lenses that enhance colour contrast 4
- Colour vision apps that identify colours using a smartphone camera
- Colour-coded labelling systems with text and symbols for objects
- Screen readers and text-to-speech software that describe colours in digital content
Colour blindness is a condition which affects an individual's ability to perceive or distinguish certain colours. It normally occurs through genetic mutations that affect the light-sensitive cells located at the back of our eyes. Some types of colour blindness can impact daily activities, but you can cope with it by making use of technology and apps, using special lenses and glasses, you can label the colours, you can seek support and assistance from friends, families, support groups etc.
- Carroll J, Conway BR. Color vision. In: Handbook of Clinical Neurology [Internet]. Elsevier; 2021 [cited 2023 Oct 17]. p. 131–53. Available from: https://linkinghub.elsevier.com/retrieve/pii/B9780128213773000052
- Bowmaker JK. Visual pigments and molecular genetics of color blindness. Physiology [Internet]. 1998 Apr [cited 2023 Oct 17];13(2):63–9. Available from: https://www.physiology.org/doi/10.1152/physiologyonline.19126.96.36.199
- Birch J. Efficiency of the Ishihara test for identifying red-green colour deficiency. Oph Phys Optics [Internet]. 1997 Sep [cited 2023 Oct 17];17(5):403–8. Available from: http://doi.wiley.com/10.1111/j.1475-1313.1997.tb00072.x
- Gómez-Robledo L, Valero EM, Huertas R, Martínez-Domingo MA, Hernández-Andrés J. Do EnChroma glasses improve color vision for colourblind subjects? Opt Express [Internet]. 2018 Oct 29 [cited 2023 Oct 17];26(22):28693. Available from: https://opg.optica.org/abstract.cfm?URI=oe-26-22-28693
- Chakrabarti S. Psychosocial aspects of colour vision deficiency: Implications for a career in medicine. NMJI [Internet]. 2018 Mar 1 [cited 2023 Oct 17];31:86. Available from: https://nmji.in/psychosocial-aspects-of-colour-vision-deficiency-implications-for-a-career-in-medicine/