What is color blindness?
Color blindness means that you
have trouble seeing red, green, or blue or a mix of these colors. It’s rare
that a person sees no color at all.
Color blindness is also called
a color vision problem.
A color vision 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
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
See a picture of the eye that shows the retina and the macula.
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 isn't always inherited. In some cases, a person
can have an acquired color vision problem. This can be caused by:
- Eye problems, such as
- Injury to the eye.
- Side effects of some medicines.
What are the symptoms?
The symptoms of color
vision problems vary:
- You may be able to see some colors but not others. For instance, you may not be able to tell the difference between
red and green but can see blue and yellow.
- 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?
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 know 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.
Because a color vision problem can
have a big impact on a person's life, it is important to detect the problem as
early as possible. In children, color vision problems can affect learning
abilities and reading development. And color vision problems may limit career choices that require you to tell colors apart. Most experts
recommend eye exams for children between ages 3 and 5. Vision screening is
recommended for all children at least once before entering school, preferably
between the ages of 3 and 4.
How is it treated?