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Home » Article Library » What is Colour Blindness?

What is Colour Blindness?


Colour blindness is a condition affecting one's ability to distinguish colours under normal lighting conditions or to perceive colours as they are normally viewed. Usually, the disorder is present at birth, but it can also be a result of injuries or a number of diseases of the eye.


Colour perception is dependent upon the cones located within the retina of the eye. Humans are commonly born with three types of cones, each perceiving different wavelengths of colour. With colours, the length of the wave is directly related to the perceived colour tone. Short waves project blue tones, medium-length waves project greens and long waves produce reds. Which pigmented cone is affected has an impact on the nature and seriousness of the colour blindness.


Being a sex-linked recessive trait, many more men are green-red colour blind than females. Nevertheless, there are plenty of women who do experience some degree of colour vision deficiency, specifically blue-yellow deficiencies.


There are many cases in which individuals develop colour vision problems later in life resulting from another condition including injuries, cataracts and especially macular degeneration. Thankfully, it might be possible to reverse the condition once the cause is treated


There are several tests for the condition. The most common is the Ishihara colour exam, called after its inventor. For this test a plate is shown with a group of dots in a circle in differing colours and sizes. Inside the circle one with proper colour vision can see a digit in a particular tint. The individual's ability to make out the digit within the dots of clashing tones examines the level of red-green colour vision.


While hereditary colour blindness can't be treated, there are a few options that can help to make up for it. For some, wearing tinted lenses or glasses which minimize glare can help people to perceive the distinction between colours. Increasingly, computer applications are on the market for standard personal computers and for mobile machines that can help users enhance colour distinction depending upon their particular condition. There are also exciting experiments being conducted in gene therapy to correct the ability to perceive colours.


The extent to which colour blindness limits an individual depends on the type and degree of the condition. Some individuals can accommodate to their deficiency by learning alternative clues for coloured objects or signs. For instance, some might familiarize themselves with the shape of traffic signs in place of recognizing red, or compare objects with reference objects like green trees or the blue sky.


If you notice signs that you or your loved one could be colour blind it's recommended to get tested by an optometrist. The sooner the condition is diagnosed, the sooner you can help. Feel free to call our Calgary, AB optometrists for more information about colour blindness.