Houria Fangare
There is a reason why we don’t see the world in only black and white, life is full of colours. Colours can sway thinking, change actions, cause a reaction. However ,there are some people who are unfortunate enough to be born with a condition that makes them see colours less differently or in different shades of one or two colours. This condition is called “Colour Blindness” or “Daltonism” referred to John Dalton, the well known scientist who introduced the atomic theory.
John Dalton was the first scientist to study colour blindness after discovering that he suffered from it.His interest in colour began in 1970 when he started studying Botany and noticed that he had problems in naming the colours of the plants, then he began to collect silk ribands in various colours from a friend of him who was a dyer in order to compare his perception with those of his acquaintances.
Dalton said “The part of the image which others called red, appears to me a little more like a shade or a defect of a light; after that, the orange, yellow and green seem like one colour, making what I should call different shades of yellow.”
Dalton discovered that his brother had the same perception of colours as him and concluded that the two of them must have a hereditary problem. He suggested that they inherited “coloured medium” or blue colouration in the humor of the eye, filtering colours incorrectly.
In order to test his theory, he graciously donated his own eyes to medical science. After his death, doctor Joseph Ransome removed Dalton’s eyes and quickly discovered the clarity of his eye humor, disproving Dalton’s colouration theory.
Fortunately, Ransome left one of dalton’s eyes intact enabling other scientists after a gap of two centuries to take a retinal sample and conduct DNA analysis, where they found that he was a strong Deuteranope, lacking cones that respond to the colour green. The green cone is one of the 3 photoreceptors ( green, blue, red) responsible for normal vision which allow people to see a wide spectrum of colours, any abnormality or defect leads to an abnormal colour vision.
Today, 2.7 million people around the world are colour blind, 8% of all men are suffering from the condition since it is X-linked as well as 0.5 % of all women. Unfortunately, there is no cure for colour blindness, only coping strategies which may help a colour blind person be more colour oriented, some people use special contact lenses or glasses which improve their perception of colours, other people learn to recognize items by order rather than colour. There is also a variety of downloadable apps to assist with colour detection. Apparently, the colour blind needs special modifications in their lifestyle. It is so hard to drive a car when you can’t tell whether the traffic light is red or green.
Many of our daily activities depend on colours. Be grateful for seeing all these colours around you.
References:
https://www.college-optometrists.org/the-college/museum/online-exhibitions/virtual-colour-vision-gallery/john-dalton-a-visual-error.html
https://enchroma.com/blogs/beyond-color/john-dalton-the-father-of-color-blindness
https://www.allaboutvision.com/conditions/colordeficiency.htm
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