Colour blindness is an umbrella term given to a range of vision deficiencies that result in the sufferer being unable to see colour in the same ways that the majority of other people see colour. There are various different types of colour blindness, and the term does not necessarily mean that the sufferer is completely unable to see colours. Most sufferers have problems with their eyes which prevent them from seeing red, green or blue light properly.

Is Colour Blindness common?

In the United Kingdom, it is estimated that around 4.5% of the population suffer from some form of colour blindness. It is a common myth that only men are affected by these disorders, however men are far more likely to be affected. Around 1 in 8 men have symptoms of colour blindness, but only 1 in 200 women are affected. People of Caucasian descent are more likely to suffer from these issues than people of African descent.

Types of Colour Blindness

There are a lot of different types of colour blindness. Three major types of colour blindness are protanomaly, deuteranomaly and tritanomly. Protanomaly is a reduced sensitivity to red light, deuteranomoly is a problem sensing green light, and tritanomoly is a reduced sensitivity to blue light. Deueranomoly is the most common type of colour blindness, whereas tritanomoly is an extremely rare form in the United Kingdom. The conditions are not mutually exclusive.

Many people with colour blindness have reduced sensitivities to two or more colours of light. The most common form of colour blindness is red-green colour blindness, where people have protonomaly and deuteranomaly. These people struggle to distinguish browns, blues, oranges and greens. If the person is unable to perceive a light colour at all, the names are slightly different, but come from similar word roots. Protonopic people cannot perceive red light at all, deuteranopic people cannot see green light and tritanopic people cannot see red light.

A very rare form of colour blindness is monochromacy (or achromatopsia). People who suffer from achromatopsia cannot distinguish any colour at all, and they see the world in different shades of grey, black and white. It is estimated that only about 1 in 33,000 have this form of colour blindness, however many people in the United Kingdom have been diagnosed as having “total colour blindness” because many high-street opticians are not experienced with colour blindness.

What causes Colour Blindness?

The vast majority of people who suffer from colour blindness in the United Kingdom are born with the condition. Red, green and blue colour blindness is all caused by a fault on the X chromosome, and this fault is normally passed down from the parents. Because the fault is on the X chromosome, men are more likely to be affected by it than women. For a woman to be affected, both parents would normally have to be carriers of the defective gene.

In a smaller number of cases, colour blindness develops over time, normally as a result of an illness or physical trauma.

Diabetes, liver disorders, eye problems and multiple sclerosis are all leading causes of acquired colour blindness. Some medication may also have colour blindness as a rare side effect. These illness and medications affect the way that the rods and cones in the eye react to light hitting them. A failure to react in the normal way can cause colour blindness.

Can people live well with Colour Blindness?

Colour blindness does cause certain problems for sufferers; however it is possible to learn how to cope with this condition. People with colour blindness may struggle with selecting food or clothing which requires them to tell the differences between colours. In the kitchen, dishes may look cooked when they are still raw. Food which looks delicious to other people may look an unpalatable shade of brown. Most people learn to adapt their behaviour so that they can continue to lead a normal life.

How is Colour Blindness diagnosed?

It can be difficult to identify colour vision deficiencies, because people are often unaware that they are perceiving colours differently to their peers. The most common test is known as the Ishihara Plate test. In this test, people are shown a series of plates with coloured spots on. Hidden in these spots is information which either can or cannot be seen by people with a colour blindness issue. Certain information can only be seen easily by people with colour deficiency issues.

How is Colour Blindness treated?

At present, there is no known treatment for genetic colour blindness. Glasses and filters may be available to help people to differentiate colours, although some people say that these actually exacerbate their issues. The effects of acquired colour blindness can sometimes be treated by isolating the cause of the problem and treating that instead. However, this does not work in some cases and the damage may be irreversible.