In Australia, around 8% of males and 0.4% of females suffer a colour vision deficiency of some kind. Contrary to what many believe, colour vision deficiency (colour blindness) is not a form of blindness, rather a deficiency in the way you see colours making it difficult to distinguish certain colours, such as blue and yellow or red and green. Abernethy Owens are the trusted independent optometrists in Perth, we have a team of highly skilled  Optometrists experienced in diagnosing and treating a wide range of optical conditions. Here we will explore the different types of colour vision deficiencies, what causes them and how they can affect your vision.

What Causes a Colour Vision Deficiency?

A colour vision deficiency occurs when light-sensitive cells in the retina fail to respond to variations in wavelengths of light that enable you to see a broad spectrum of colours.

The human retina has two types of photoreceptor cells that are responsible for colour vision:

Rod cells - Sensitive to light, but rods are incapable of perceiving colour. There are approximately 100 million rods in the human retina and they detect objects around us at night and shades of black, grey and white.

Cone cells - These react to light and help us to see detailed objects. The three different cone cells detect red, green and blue and it is the combination of these colours that allow us to pick up the wide array of colours we normally see.

The majority of colour vision problems are genetic and are often related to deficiencies in certain types of cones or an outright absence of these cones.

There are also less common causes including:

  • Accidents and other trauma, which may cause swelling of the brain in the occipital lobe
  • Damage to the retina caused by exposure to ultraviolet light
  • Neurological conditions such as Parkinson’s Disease
  • A deficiency of vitamin A
  • Degenerative diseases of the eye - macular degeneration, glaucoma, retinal damage from diabetes and cataracts
  • Damage to retinal cells caused by aging

The Different Types of Colour Vision Deficiencies

The most common type of colour blindness makes it hard to tell the difference between red and green. Another type makes it hard to tell the difference between blue and yellow.

Red-green colour deficiencies

  • Deuteranomaly - the most common type, which makes green look more red.
  • Protanomaly - makes red look more green and less bright.

Both of the above make you unable to tell the difference between red and green at all. Both are mild and usually don’t get in the way of normal everyday activities.

Blue-yellow colour deficiencies

  • Tritanomaly - makes it hard to tell the difference between blue and green, and between yellow and red.
  • Tritanopia - means you are unable to distinguish between blue and green, purple and red, and yellow and pink. It also makes colours look less bright.


Also known as complete colour blindness. This is extremely rare, and means you cannot see any colours at all. You may also have trouble seeing clearly and you may be more sensitive to light.

What Are the Symptoms?

Symptoms are often so mild many people may not notice them. Additionally, as we get used to the way we see colours, many people don’t ever know they have a colour deficiency. If you suffer from colour blindness or a colour vision deficiency, you may have trouble:

  • Distinguishing between colours
  • Understanding the brightness of colours
  • Recognising different shades of colours

People with very serious cases might have other symptoms as well including quick side-to-side eye movements or sensitivity to light.

What Are the Treatment Options?

There is no current treatment available that can cure colour vision deficiencies. Most of the time, colour blindness doesn’t cause serious problems and most people find ways to adjust to it. However, if the deficiency is affecting everyday life, Optometrists can supply special contact lenses and glasses that may help. These lenses use light-filtering technology to enhance colour perception, which can improve the ability to see the broad spectrum of bright colours.

If you have difficulty distinguishing colours or if you suspect you have a colour vision deficiency, visit an experienced Optometrist to discuss if specialised glasses would be a good option for you. Book an appointment online today with Perth’s leading independent optometrists, Abernethy Owens.