Blindnessdeficiency

Whatever you choose to call it...

Daltonism

Many people believe that colour blindness results in the individual seeing only in black and white. In fact colour blind people can see colour it’s just the shade and vibrancy that varies depending on the type of colour blindness.

In Colour blindness there are a reduced number of cone cells in the retina of the eye. It is the retina that is responsible for colour vision and there are three types of cone cell.

These coloured cells are, red, blue and green that are sensitive to light. For each of these cones there exists a specific colour absorption curve with peaks at different points in the colour spectrum. When one type of conemalfunctions the colour that this cone would normally absorb is altered. This changes the colour perception, resulting in a different way of perceiving colour that results in colour blindness.

It's not all black and white, IT'S

There are several forms of colour blindness. The most common form is red/green colour blindness, which involves the confusion of red and green and is a common hereditary condition which means it is usually passed down from the individuals parents.

The effects of colour blindness can be mild, moderate or severe depending upon the defect. If you have inherited colour blindness your condition will stay the same throughout your life – it won’t get any better or worse.

Because colour blindness can have a big impact on a person’s life, it is important to detect the problem as early as possible. In children, colour vision problems can affect learning abilities, reading development, and may limit career choices that require you to tell colours apart. Most experts recommend eye exams for children between ages 3 and 5.

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The three types of cones translate into three main types of

colour blindness: Deutan (green), Protan (red) and Tritan (blue)

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Rg BThe Tritan (blue) colour blind have the blue end of the spectrum missing or altered.

R BThe Deutan (green) colour blind have the green end of the spectrum missing or altered.

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The Protan (red) colour blind have the red end of the spectrum missing or altered.

DEUTAN

(Thats one, two, three in greek)

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Almost 100 years ago in 1917, Dr Ishihara introduced the most well known colour blindness test....The Ishihara Test.

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The Ishihara test can be taken by your local optometrist or your general medical practitioner where you will be asked to state the numbers on each plate. If you have abnormal colour vision you will not be able to see the numbers because their colours will look the same as the colours of the background dots. Dr Ishihara designed this test very cleverly because for some of the plates those with abnormal colour vision will see different numbers from those seen by someone with normal colourvision; and on other plates those with normal colour vision do not see any numbers but those with colour blindness do.

If you make errors in more than 3 plates you are very likely to have abnormal colour vision and if you make more than 6 errors it is almost certain.

The Ishihara test consists of a set of coloured dotted plates, each of them showing either a number or a path. They are commonly used to detect colour blindness of the basic colours, red, blue and green. If you have abnormal colour vision (colour blindness) you will struggle to, or not evenbe able to distinguish the numbers or pattern.

Shinobu Ishihara (1879-1963). While working at the Military Medical School he was asked to devise a test to screen military recruits for abnormalities ofcolour blindness. His assistant was a colour blind physician who helped him test the plates.

Interview with colour blind male aged 22

What colours do you struggle to distinguish?Reds and greens.

What age did it become apparent that you were colour blind?I had a test for colour blindness when I was around 6 years old.

Did you struggle having colour blindness as a child?

Not really, I did have problems with colouring pictures and similar things accurately; this was because the colours I chose to use were not always the colours I thought they were.

Do you feel being colourblind is a disability?

Slightly, due to the fact I cannot perform certain tasks efficiently. That said I just carry on as normal, it hasn’t caused any direct inconvenience within my life currently.

How often do you find being colour blind effects your profession?

I am an insulation engineer by trade which doesn’t require me to distinguish any unusual colours.

How often do you find being colour blind effects your daily life?

Well if I am playing a computer game or doing any sort of colour based puzzle I will require aid from people around me from time to time, this isn’t a regular occurrence but can be quite irritating if there is no one there to aid me.

everything seems rather washed out

People began to start questioning me on the colour of objects around me

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Do you view colour blindness as a negative thing?

In a way yes, because I am always at a disadvantage. It can also get rather irritating when people realise that I am colour blind because they begin to start questioning me on the colour of the object around me. It would be nice to be able to see things the way other people can see them. As far as I can tell the best way to describe my colour blindness is that everything seems rather washed out, rather than vibrant.

That said though, I do like the fact that I see things differently to others. It can also be rather beneficial in some cases, as I have found that my colour blindness effects the way my eyes absorb light. Even the slightest sunlight can irritate my eyes, but it also means that I am able to see slightly better in the dark than most people.

Have you ever had an Ishihara test?

Yes I have had an Ishihara test, multiple times, mainly when I go to have my eyes tested at new opticians. I struggle quite a lot with these tests as I am not able to distinguish the patterns or numbers most of the time.

99% of all colour blind people are not really colour blind but colour deficient; the term color blindness is misleading.

Strongly colour blind people might only be able to tell about 20 hues apart from each other, with normal colour vision this number raises to more than 100 different hues.

A father can’t pass his red-green colour blindness on to his sons.

99% of all colour blind people are suffering from red-green colour blindness.

In certain countries you need normal colour vision to get a drivers license.

There is no treatment or cure for colour blindness.

There are people which are really suffering from complete colour blindness, which is called achromatopsia or monochromacy.

John Dalton wrote the first known scientific paper regarding colour blindness.

Police officer, firefighter, and airline pilot are the most famous jobs which require normal colour vision.

Quite a lot of people with normal colour vision can’t pass an Ishihara plates test free of errors.

things you didn't know about colour blindness

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Interview with colour blind male GRAPHIC DESIGNER

What colours do you struggle to distinguish?

I struggle with Green, purple and blue.

What age did it become apparent that you were colour blind?

I knew when I was around the age of 5 or 6, but I wasn’t actually tested until around 8 or 9.

Did you struggle having colour blindness as a child?

Yes, I would colour skies purple, the leaves brown and the trunk green. It wasn’t a major issue but it was funny for the kids around me. As I got a bit older I got use to it and actually asked people what colour it was with my pencils. By the time I was 10 or 11 I had got use to being colour blind.

Do you feel being colourblind is a disability?

No, well it is in a sense, but disability in terms of how we interpret that word is quite extreme to explain what I have. I am unable to do what the majority of people do, so in a literal sense I have a disability, butnot in a sense where I am at a disadvantage in a serious way.

I WAS told being a graphicdesigner would be difficult

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I WOULD COLOUR SKIES PURPLE, LEAVES BROWN AND TREE TRUNKS GREEN.

How often do you find being colour blind effects your profession?

I was told when I found out I was colour blind thatbeing a graphic designer would be difficult, but with the software I use I pick colours based on what I already know. I know where the green section is and where the brown section is so I work my way from there. My colour blindness is the range in between the colours. Typical brown I can see or typical green, like grass green, I can see those. I know what green is, but with the intermittency between green and brown with lighter shades I can’t see that. It’s not ideal for someone in art and design but I’ve got use to it.

Do you view colour blindness as a negative thing?

No, not really. There can be weird advantages to it.

I don’t know if it’s a gender difference but when it comes to the colour red my wife will say it’s scarlet or some other sort of facet or a tone of red, where I usually just say red. I often find, especially in teaching that females tend to be a little bit more sensitive tovariations of colour than men. I don’t know how I’d back this up it’s just my experience.

Have you ever had an Ishihara test?

Yes, I had an Ishihara test when I was at school.

How often do you find being colour blind effects your daily life?

It doesn’t really inhibit anything in normal daily life; I am on the mild side of colour blindness.

Has being colour blind ever effected a design project?

No, if I have any issues I use the colour picker, and pick the colour from the pantone I recognise. You adopt strategy’s to get round it, if you’ve lived with it all your life it becomes habit.

THERE CAN BE WEIRD ADVANTAGES TO IT.

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"COLOUR BLIND ADVANTAGESIn WWII analysis of aerial photographs with teams that included colour blind individuals were more successful. The colour blind individuals were able to detect unusual patterns in ways that normal vision people couldn’t.

And more recently, researchers from the University of Calgary showed that colour blind monkeys are better at hunting insects. The monkey’s with colour blindness caught more insects, presumably because they could see through the insects’ camouflage. Evolutionary speculators have also suggested that a group of hunters that contained at least one person who is colour blind would be more successful, and so this trait might continue to be found in a portion of the population.

RISK FACTORSSometimes colour blindness occurs because of diseases such as macular degeneration or from side effects of medicines.

Colour blindness needn’t stop someone driving, because traffic lights can be distinguished by the position of the light. However, it can be an obstacle to particular careers where good colour vision is important, including pilots, electricians, train drivers and some jobs in the printing, fashion and design industries.

The exact physical causes of colour blindness are still being researched but it is believed that colour blindness is usually caused by faulty cones, or a fault in the pathway from the cone to the brain.