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Colour blindness, or colour vision deficiency (CVD), is a condition that affects an individual’s ability to perceive and differentiate colours. Colour blindness is primarily inherited, however, symptoms can develop later on in life. Males are also much more likely to inherit the disease, as 1 in 12 males are colourblind while only 1 in 200 females are colourblind.
The disorder is caused primarily by faulty photoreceptor cells, namely the cone cells, as they allow our eyes to perceive colours. Cone cells are also specialised, and can only absorb certain ranges of wavelengths of light. For this reason, cone cells are separated into 3 types: S-cones, M-cones, and L-cones. The different cones absorb short, medium, and long wavelengths of light respectively and each cone targets a different primary colour of light due to this difference. S-cones absorb blue light, M-cones absorb green light, and L-cones absorb red light. Colour blindness is caused by the loss or damage of any one or more of these different types of cone cells, and an individual’s vision will be affected differently based on the severity of the damage as well as which cone cell is affected.
Colour blindness that affects S-cones and M-cones, more commonly known as red-green colourblindness, is the most common form of the disease. Red-green colourblindness itself has 4 different types, protanopia, where there are no red cones, protanomaly, where there are few red cones, deuteranopia, where there are no green cones, and deuteranomaly, where there are few green cones. People with these 4 types of CVD will usually see many colours in the world as a murky green, with trouble differentiating between, reds, oranges, browns, and greens.
Blue-yellow colour blindness is a significantly rarer condition, and affects solely the L-cones, or blue cones. Blue-yellow colour blindness includes tritanopia, entailing a lack of blue cones, and tritanomaly, producing a reduction of blue cones. People with blue-yellow colour blindness typically find it hard to differentiate between the cool colours, blue, green, and purple, and between the warm colours, red, yellow, and orange.
None of the aforementioned conditions are quite as severe as achromatopsia, also known as monochromacy. As the name suggests, people with monochromacy see a monochrome world, with a complete lack of colour. Achromatopsia is caused by the loss of more than 1 type of cone cell, and is the rarest colour blindness condition, only affecting 1 in every 33000 people.
A common treatment for colourblind people is colour blind glasses or contact lenses. Colour blind glasses simply attempt to exaggerate and saturate the differences in the colours that an individual struggles to perceive. There are not, however, any cures or treatments for monochromacy as modern technology is still not advanced enough to deal with the condition.
While colour blindness is considered a fairly mild condition, it affects many people around the world and impacts millions of people’s lives everyday. There is a strong likelihood that you yourself have met someone who is dealing with this condition, and it is important to be grateful for all the beautiful colours that make up our world, as there are a plethora of individuals who are unable to enjoy our vibrant reality in the same way.
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