Colour Vision deficiency or Colour Blindness– What is the correct term?

Colour vision deficiency is the inability to distinguish certain shades of colour. The term “colour blindness” is also used to describe this visual condition, but very few people are entirely colour blind. You can use whatever name you feel most comfortable with.

Some problems with colour vision are not caused by gene mutations. These nonhereditary conditions are described as acquired Colour Vision Deficiencies. They can be caused by other eye disorders, such as diseases involving the retina, the nerve that carries visual information from the eye to the brain (the optic nerve), or areas of the brain involved in processing visual information. Acquired colour vision deficiencies can also be side effects of certain drugs, such as chloroquine (which is used to treat malaria), or result from exposure to particular chemicals, such as organic solvents.

Some diseases that can cause colour deficits are:

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

Colour Blindness represents a group of conditions that affect the perception of colour. Red-green colour vision defects are the most common form of colour vision deficiency.

Affected individuals have trouble distinguishing between some shades of red, yellow, and green. Blue-yellow colour vision defects (also called Tritan defects), which are rarer, cause problems with differentiating shades of blue and green and cause difficulty distinguishing dark blue from black. These two forms of colour vision deficiency disrupt colour perception but do not affect the sharpness of vision (visual acuity).

The condition is often inherited. Other causes include certain eye diseases and medication. More men than women are affected. It is caused by a common X-linked recessive gene, which is passed from mother to son.

Colour blindness usually involves the inability to distinguish between shades of red and green.


How it Happens – Technical Stuff!

Mutations in the OPN1LWOPN1MW, and OPN1SW genes cause the forms of colour vision deficiency described above. The proteins produced from these genes play essential roles in colour vision. They are found in the retina, which is the light-sensitive tissue at the back of the eye. The retina contains two types of light receptor cells, called rods and cones, which transmit visual signals from the eye to the brain. Rods provide vision in low light. Cones provide vision in bright light, including colour vision. There are three types of cones, each containing a specific pigment (a photopigment called an opsin) that is most sensitive to particular wavelengths of light. The brain combines input from all three types of cones to produce normal colour vision.

At Colour Vision Optical we don’t like referring to it as “Colour Vision Deficiency” or “Colour Blindness” – people with this condition aren’t deficient or blind! So we propose a new term – “iRochromatic“, and as there is no treatment for inherited colour blindness, we have developed iRo Lenses which help you see colours as you have never seen them before.