Eye Diseases and Disorders

Colour Vision Deficiency

Colour Vision Deficiency

What is Colour Vision Deficiency?

Colour vision deficiency, or CVD, (sometimes referred to as ‘colour blindness’) is a common disorder where people are more likely to confuse some colours whilst retaining the ability to distinguish others. Colour vision deficiency can affect up to 8% of males but only 0.5% of females. The inability to see any colour at all is extremely rare, and usually sufferers are more likely to confuse some colours whilst retaining the ability to distinguish others. Most commonly, people will have problems distinguishing between red and green.


Colour blindness is a genetic condition usually passed from mother to son, but it can also result from some diseases such as:

  • Diabetes
  • Alzheimer’s disease
  • Chronic alcoholism
  • Glaucoma
  • Parkinson’s disease
  • Leukaemia
  • Macular Degeneration
  • Multiple sclerosis
  • Sickle cell anaemia

Other causes include some medications or exposure to chemicals such as fertilisers, and the ability to see colours can also lessen with age.

Symptoms CVD

The symptoms of CVD may be observed by parents when children are young. In other cases, symptoms are so slight, they may not even be noticed. Common symptoms of colour blindness include:

  • Difficulty distinguishing between colours
  • Inability to see shades or tones of the same colour
  • Rapid eye movement (in rare cases)

It is generally diagnosed during an eye examination using special coloured pictures called Ishihara plates which contain numbers which can be recognised with normal colour vision.

Treatment for CVD

There is no known treatment for CVD. Fortunately, the vision of most colour-blind people is normal in all other respects and certain adaptation methods are all that is required.

These symptoms can also be a sign of other eye conditions. If you have any of the symptoms, please check with your eye care practitioner.