Color blind - What does that really mean?

Color blindness means you have trouble seeing red, green, blue or a mix of these colors. It’s rare that a person sees no color at all or black and white. Most patients who are labeled as color blind are really only color deficient and that problem can change your life. It makes it harder to learn and read, and you may not be able to have certain careers. But children and adults with color vision problems can learn to make up for their problems seeing color.

What causes color blindness?

Most color vision problems are inherited (genetic) and are present at birth.
People usually have three types of cone cells in the eye. Each type senses either red, green, or blue light. You see color when your cone cells sense different amounts of these three basic colors. Most cone cells are found in the macula, which is the central part of the retina.

Inherited color blindness happens when you don't have one of these types of cone cells or they don't work right. You may not see one of these three basic colors, or you may see a different shade of that color or a different color. This type of color vision problem doesn't change over time.

A color vision problem is not always inherited. In some cases, a person can have an acquired color vision problem. This can be caused by:

Aging.
Eye problems, such as glaucoma, macular degeneration, cataracts, or diabetic retinopathy.
Injury to the eye.
Side effects of some medicines.


What are the symptoms?
The symptoms of color vision problems vary:
You may see many colors, so you may not know that you see color differently from others.
You may only be able to see a few shades of color, while most people can see thousands of colors.
In rare cases, you may see only black, white, and gray.


How is color blindness diagnosed?
Tests measure how well you recognize different colors. In one type of test, you look at sets of colored dots and try to find a pattern in them, such as a letter or number. The patterns you see help your doctor determine which colors you have trouble with.
In another type of test, you arrange colored chips in order according to how similar the colors are. People with color vision problems cannot arrange the colored chips correctly.

How is it treated?
Inherited color vision problems cannot be treated or corrected. In some cases a special ophthalmic lens or contact lens, called a red lens, can be worm to a help a color deficient patient detect colors better. The red lens looks very different when worn on the eye. While unacceptable cosmetically this is a special use lens treatment. The choice of such a treatment is often driven by a work related task.

Some acquired color vision problems can be treated, depending on the cause. For example, if a cataract is causing a problem with color vision, surgery to remove the cataract may restore normal color vision.