Close up of green and red lens on phoropter
Close up of green and red lens on phoropter

Color Blindness

Most people with color blindness (or color deficiency) are born with it, but sometimes it doesn’t show up until later in life. Nearly all people who are “color blind” can see colors but have difficulty distinguishing between certain colors.

Except in the most severe form, color blindness does not affect sharpness of vision. Not all people who are color blind have trouble with the same colors—most cannot distinguish between reds and greens, while some cannot separate blues from yellows. A very small group have a condition called monochromatism (or achromatopsia), which only allows them to see in shades of grey. This rare condition is associated with:

  • Amblyopia (or lazy eye)
  • Nystagmus (involuntary rapid, repetitive movement of the eyes)
  • Light sensitivity
  • Poor vision

Color blindness is a genetic condition caused by a difference in how one or more of the light-sensitive cells found in the retina of the eye respond to certain colors. These cells, called cones, sense wavelengths of light and enable the retina to distinguish between colors. This difference in sensitivity in one or more cones can make a person color blind.

Men are much more likely to have color blindness (or color deficiency) than women, who seldom have the problem. Color blindness of various kinds affects roughly one in 10 males and is more common among men of Northern European descent.

Anyone can be born with or acquire color blindness, but some are at higher risk than others. These include people who have certain conditions such as:

Most color vision issues that occur later in life are the result of disease, trauma, toxic effects from drugs, metabolic disease, or vascular disease. Certain drugs may also increase your risk for acquiring color blindness.

Symptoms of Color Blindness

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

  • Difficulty distinguishing between colors or the brightness of colors in the usual way
  • Inability to see shades or tones of the same color, which happens most with red and green, or blue and yellow

Treatment for Color Blindness

There is no known cure for color blindness. Special contact lenses and glasses are available with filters to help color deficiencies, if needed. Fortunately, the vision of most color-blind people is normal in all other respects; most of the time, color blindness doesn’t cause serious problems and certain adaptation methods are all that is required.