Seeing the World Differently: Understanding Colour Vision Deficiency

Colour blindness, more accurately termed Colour Vision Deficiency (CVD), affects a significant portion of the population by altering their ability to perceive certain colours. Whether it's the result of genetics or acquired later in life, CVD presents unique challenges and insights into how we see the world. Let's dive into what CVD is, its types, and how it's diagnosed and managed.

What is Colour Vision Deficiency?

Colour Vision Deficiency occurs when there's an inability or reduced ability to see certain colours or to tell them apart. This is generally an inherited condition which passes down the female side of the family.

How Common is Colour Vision Deficiency in Australia?

According to the Australian Institute of Health and Welfare (AIHW), over half a million Australians experience colour blindness. Men are 16 times more likely to be affected than women.

Types of Colour Vision Deficiency

Colour vision relies on three types of photoreceptors (cones) in the eye, red cones, green cones or blue cones. The brain processes signals from these cones to create our perception of colour.

Congenital CVD: This is present from birth due to genetic changes, typically affecting red or green cones. The severity varies, with some individuals seeing a limited spectrum of colours. In severe cases, they perceive the world in blue and yellow hues, although most retain some sensitivity to the affected colours.

Acquired CVD: This develops later in life due to conditions affecting the eye or brain, diseases, medications, or injuries. Unlike congenital CVD, acquired CVD can affect any part of the colour pathway.

Common Misconceptions

"Colour blindness" is a misleading term; true colour blindness, seeing only shades of grey, is really rare. Most people with CVD are colour deficient, which means they see a narrower spectrum of colours due to non-functioning or partly functioning colour channels. The severity of CVD varies; some people might have a particular colour cone missing while others may still have the cone receptor but it just doesn’t function properly.

Diagnosing CVD: The Ishihara Test

The Ishihara test is a common method for screening red-green colour deficiencies. It uses plates with coloured dots forming numbers or patterns visible only to those with normal colour vision. However, it doesn't assess the severity or other types of deficiencies.

Daily Challenges with CVD

CVD can impact daily activities, from coordinating clothing to cooking, where distinguishing the ripeness of fruit or how well cooked your meat is can be challenging. Parents with CVD might struggle to notice their child's sunburn, and sports can become tricky when trying to spot a red ball on green grass. Traffic lights also pose a challenge, particularly for those who develop CVD later in life.

Career Considerations

Most jobs do not require specific colour vision standards. However, certain professions, like commercial pilots, train drivers, and maritime workers, do impose standards to prevent safety risks. There are though some jobs where having ‘normal’ colour vision is important - such as an electrician, painter or graphic designer.

Have you ever wondered how things appear to people with a colour vision deficiency?

If you have any questions or would like to know more about your colour vision, please get in touch with us.