What is color
blindness?
Color blindness is a vision problem that
makes it hard to tell the difference between certain colors.
If you are color blind, it usually does not mean you see
everything in black and white or shades of gray. Full color
blindness is very rare. Most color-blind people have trouble
with just 1 or 2 colors. Usually the colors they have the
most trouble telling the difference between are red and
green. Shades of red and green might look brownish to a
color-blind person.
How does it
occur?
You see in color because the retina at the
back of the eye has special cells called cones. There are 3
types of cones: cones for red light, cones for green light,
and cones for blue light. These 3 types of cones mix the
colors together to create all of the colors people see. In a
color-blind person, the red and green cones are very similar
to each other so that it is difficult to tell the difference
between red and green colors. This causes an abnormal mix of
color and color confusion.
Color blindness is usually an inherited and
lifelong condition. It is most commonly passed from mother
to son. A woman can be a "carrier" of the gene but will
usually not be color blind herself. Men cannot be just
carriers of the gene. If a man has the color blindness gene
then he is color blind. For that reason, men are more
commonly color blind than women.
Rarely an eye disease can cause you to
become color blind later in life. Usually color blindness is
not caused by a disease, but some retinal diseases (such as
age-related macular degeneration) may cause problems with
color vision.
How is it
diagnosed?
Your eye doctor can do a very simple test
for color blindness. You look at a special test book that
has a pattern of small colored circles. Some of the circles
on the page are a different color and form a number. A color
blind person will not be able to see the number because it
will appear as the same color as the other circles on the
page. The test book has about a dozen of these patterns in
it to make sure of the diagnosis and to judge the severity
of the color blindness. This test is usually easy enough
that it is possible to get good results even with young
children.
In some cases your eye doctor may refer you
to another specialist to do more detailed testing to figure
out exactly what type of color blindness you have.
How is it
treated?
Usually there is no need to treat color
blindness. People with color blindness learn to tell the
differences between colors. For example, green might look
brighter than red. If a person is severely color blind,
occasionally a red tinted contact lens is prescribed for
just one eye. This may help the person see colors a little
better.
How can I
take care of myself?
Usually nothing needs to be done. You many
find that some tasks are frustrating such as:
- judging traffic lights
- coloring with markers or crayons
- matching clothes
- reading color-coded maps or weather
charts
- knowing if fruits are ripe or if meat
is rare or well-done.
In some cases, a color blind person may need to avoid
careers that require excellent color vision. However, there
are many color blind electricians who can easily work with
multi-colored wires. Most of the time you can learn to
adjust by using other cues such as looking for the position
of the light on a traffic signal rather than the color or
looking for subtle color differences (red may appear darker
than green). Parents may need to give their color blind
child more assistance picking out clothes until the child
can learn how to match colors.
