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A Differently Coloured Life: Understanding Colour Blindness

Colour blindness is a disorder affecting one's ability to view colours under normal lighting conditions or to discern colours as they are normally seen. Commonly, the disorder is genetic, but it can also be caused by accidents or a variety of eye diseases.

The discernment of colour is dependent upon the cones located in the eye. Humans are generally born with three kinds of cones, each of which perceives various wavelengths of colour tone. When it comes to shades of colour, the length of the wave is directly linked to the resulting colour. Long waves produce red tones, moderately-sized waves produce greens and short waves are perceived as blue tones. The type of cone that is affected impacts the spectrum and seriousness of the colour blindness.

Because it is a sex-linked genetically recessive trait, many more males are found to be red-green colour blind than females. Nevertheless, there are a number of females who do suffer some degree of colour blindness, specifically blue-yellow colour blindness.

Colour vision deficiencies are not a debilitating disability, but they can harm educational growth and work performance. The inability to distinguish colours as friends do can harm a student's confidence. For individuals of working age, colour blindness could present a disadvantage when running against colleagues trying to advance in certain fields.

There are a few examinations for the condition. The most common is the Ishihara colour test, called after its designer. In this test, a patient views a plate with a group of dots in a circle in different colours and sizes. Within the circle appears a number in a particular tint. The patient's ability to make out the digit within the dots of contrasting shades indicates the level of red-green colour sight.

Even though genetic colour vision deficiencies can't be corrected, there are some measures that might improve the situation. Some evidence shows that wearing coloured contacts or glasses which block glare can help to see the distinction between colours. Increasingly, computer applications are being developed for common personal computers and even for smaller devices that can assist people to distinguish colour better depending on their specific diagnosis. There are also interesting experiments being conducted in gene therapy to enhance the ability to distinguish colours.

The extent to which colour blindness limits an individual is dependent upon the type and severity of the deficiency. Some individuals can accommodate to their condition by learning alternative clues for coloured objects or signs. For example, they can familiarize themselves with the shapes of traffic signs instead of recognizing red, or contrast items with reference objects like the blue sky or green grass.

If you notice signs that you or a loved one could have a colour vision deficiency it's advised to see an eye doctor. The earlier you are aware of a problem, the sooner you can help. Contact our Salmon Arm, BC optometry practice to schedule an exam.


Please be advised that all office visits including exams, frame selections, repairs, pick-ups, and drop-offs are by appointment only. We are required to wear a face mask in our office and ask that you bring yours to your appointment.

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Thank you.

The Shuswap Optometric Team