Colour VISION DEFECTS: Symptoms, Causes & How To Adapt

What are Colour Vision Defects?

There are some people who have difficulty seeing different colours, or get them mixed up. This are called colour vision defects. They're most common with red and green tones, but people can also have difficulty with blue and yellow. Men are  more likely to be colour defective than women; approximately one in 12 men and one in 200 women are affected around the world.

What Does It Mean To Be Colour Defective?

Colour vision defects can impact everyday life depending on their severity and can in some instances be dangerous, for example, not being able to tell the difference between the colours of traffic light .

People with minor colour vision defects may only find out by accident, such as when a friend compliments their red dress they in fact thought was brown. This shift in perspective can be disorienting and shocking for the person, to find out things are not as they look. In this case, it’s recommended to get an eye test at your local optometrist.

  • Colour Defect

What Causes Colour Vision Defects?

Colour vision issues happen because of a problem with the pigments in the eye. There are cells on the retina (the light sensitive cells at the back of the eye) that react to light called cones and rods. The cones contain photopigments which react to different wavelengths of light, these correspond to certain colours. When all the cones have all the correct pigments, vision is fine, but with even one faulty pigment, a person may not see certain colours correctly.

If there are no pigments in the cones at all, this is known as "achromatopsia', which means colour can’t be seen at all, but this is a rare condition. So if the green photopigment doesn’t work properly, the person may be red/green colour defective, meaning they may struggle to differentiate between varying shades of red, brown, green and orange.

Who Is Prone To Colour Vision Defects?

There are several causes of colour vision defects, but the most common is genetic or hereditary, meaning it is passed down by a parent. Other reasons people can be colour defective include:

  • Diabetes
  • Age-related Macular Degeneration (AMD)
  • MS (Multiple Sclerosis)
  • Other eye conditions such as cataracts (when the eye's crystalline lens becomes cloudy) or glaucoma (a group of eye diseases that cause damage to the optic nerve)
  • Eye injury
  • Neurological disorders such as Parkinson’s
  • Age-related colour vision defects

Hereditary colour vision defects impact both eyes, though occasionally it can be in one eye only.

  • Colour Vision Testing

What Are The Tests for Colour Vision?

There are both screening tests to detect colour vision problems and more in-depth tests available to help understand the type of colour vision defect and it's severity. The Ishihara Colour Test is commonly used to broadly detect a colour vision issue. It involves the patient looking at a series of images containing colours mixed together as clusters of dots, of specific colours and sizes to test if the patient can distinguish between them. The pictures contain a number or shape, people who have a colour vision defect will struggle to see the number or shape, or they might not be able to see it at all.

Having difficulty seeing different colors?

Visit your nearest optometrist for an eye test today



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