Color Blindness and the Retina

ViteyesEye Health, Research

Have you ever:

  • found yourself wearing one navy blue sock and one black sock?
  • had a problem distinguishing very close shades of green, gray, and blue?
  • discovered that you were wearing a red shirt when you thought it was brown?

If so, you may have color vision deficiency, otherwise known as “color blindness.”

Color vision deficiency is an inability to see colors accurately. Sometimes, it involves a confusion of brightness in color variations; other times, it involves lack of shade differentiation in similar colors.

  • Ninety-nine percent of people with color vision deficiency can see some colors.
  • If you cannot see any colors at all, you have achromatopsia. You are the rare one in every 33,000 people on Earth!

Color vision deficiency results from damage to or absence of the specific cells in the retina, the light-sensitive tissue in the back of the eye. When activated by light, these special cone-shaped cells send messages to the brain via nerve impulse that focus the light and interpret color. Cone cells work with three different light frequencies: red, green, and blue.  They allow people to view 7-10 million color shades when healthy.

Red/green or blue/yellow color combinations are most commonly affected by these damaged or absent cone cells. You can have weaknesses in red perception, difficulty with green perception, complete red blindness, or total green blindness. It is possible to only see in shades of gray if you have no functioning cone cells (achromotopsia).

Most people experiencing color blindness are born with it (congenital). Some diseases can result in color vision distortions: glaucoma, diabetes, Alzheimer’s, Parkinson’s, leukemia, and sickle cell anemia. The use of certain drugs or alcoholism can also result in this condition. As people age, cataracts can also add to color vision decline, since they may tint the eye lens yellow or brown. Color blindness can be in one or both eyes.

Quick facts:

  • 320 million people are deficient in color perception in the world.
  • Eight percent of men experience it, while only one in 255 women have it.
  • Males have it more often because it is an inherited, sex-linked genetic trait.
  • Color vision deficiency does not consistently affect nationalities (Caucasian males – 10% chance while Eskimos – 1% chance)
  • Males of Northern European heritage experience color blindness most.

In order to assess whether you are experiencing this condition, vision specialists can conduct one or two exams.

  • In an Ishihara test, they will show you a card with a pattern of multiple-colored dots. You read aloud the number you see in the colored pattern.
  • In a Farnsworth Munsell 100 Hue Test, you receive four trays of items to arrange by gradually changing light to dark hues.

Color vision deficiency has no cure. However, some tinted contacts and glasses can assist with color differentiation by enhancing the brightness or darkness in your vision.

If you mistake blue for gray or red for orange, know that you are not alone. Keanu Reeves, Bill Clinton, Christopher Nolan, and Mark Zuckerberg all have red-green color blindness. Even Mr. Rogers had problems with color vision deficiency.

Remember to see your vision care provider if you are concerned about your eyesight.