Colour Blindness also termed as Coloured Vision Deficiency is a vision defect where an individual suffers from difficulty while distinguishing between certain colours like red, yellow and green. Among the photoreceptors of the eye, i.e. rods and cones, the cones are responsible for the coloured vision allowing an individual to witness an assemblage of colours. A problem with the pigments present in the cones might lead to being colour deficient or a total colour blind.

The absence of a single colour in the cones may cause an individual to have difficulty in visualizing the particular colour but the total absence of it may lead to a severe condition termed as achromatopsia.

Colour Blindness is an inherited genetic defect and is most common in males rather than their female counterparts as the genes that cause this malady, tends to affect the X-chromosomes. The two sets of the X-chromosomes in females compensate the defect of one if any.

Colour blindness may also occur due to traumatic damage to the eye or brain or it may also occur due to glaucoma, Alzheimer’s disease, cataract, ageing, diabetic retinopathy, vitamin A deficiency, medication allergy, heart problems etc.

Colour blindness


  • Difficulty in distinguishing between green and blue or red and green.
  • Colours seeming washed out or confusing.
  • Visualizing only white and grey colours

Diagnosis and Treatment

Colour blindness can be diagnosed by a doctor by conducting a number of tests:

1.    The Ishihara Colour Test:

The patient has to identify a numeric digit (made with a particular coloured dot) from a coloured plate consisting of a set of differently coloured dots.

2.    Farnsworth-Munsell 100 hue:

Consists of arranging a set of coloured chips to form a gradual colour transition in between two anchor caps

3.    HRR colour Test:

It is a red-green coloured test consisting of coloured chips or plates, to identify the tritan defects, where people confuse yellow with violet and blue with green.

There is no absolute treatment for this defect but your doctor may ease or correct it by prescribing:

  • Contact lens
  • Colour filter eyeglasses

Also, several mobile applications have been launched to help people with this deficiency to perceive the world in a better way.