Color vision deficiency


Do you have difficulty telling if something is blue or yellow, and red or green? Do other people sometimes let you know that the color you think you are seeing is wrong?

If so, these are primary signs of what is called color vision deficiency, also known as color blindness.

Color blindness is not a form of blindness at all, but rather a defect in the way you see colors.

If you are color-blind, you have difficulty distinguishing certain colors, such as blue from yellow or red from green.

It is an inherited condition that affects males more frequently than females. An estimated 8 percent of males and less than 1 percent of females have color vision problems(1).

  • Red-green color deficiency is the most common form of color blindness
  • Much more rarely, a person may inherit a trait that reduces the ability to see blue and yellow hues. This blue-yellow color deficiency usually affects men and women equally
colour vision deficiency

Color blindness is more common than you might think! 1 in 12 men is color-blind while only 1 in 200 women have the condition. This means that 95% of the color-blind community are men. 98% of those with color blindness have red-green color blindness(2).


What causes color blindness?

colour vision deficiency ishihara test

Color blindness happens because of a problem with the pigments in the eye. There are two types of retinal cells, at the very back of the eyeball, which react to light: cones and rods. The cones contain pigments which react to different wavelengths of light. When all the cones have all the correct pigments, vision is fine but with even one faulty pigment, a person might not see certain colors properly.

Should I see an ophthalmologist?

woman undergoing ishihara coulour test

If you think you suffer from color vision deficiency, seek the advice of an eye care professional to discuss if color-blind glasses are a good option for you. If you develop color vision problems when you have been able to see a full range of colors so far, then you definitely should visit your doctor. 

(2) Wong, Bang. “Color blindness.” Nature Methods, vol. 8, no. 6, 2011, p. 441. Accessed 6 Aug. 2020.