Color Blindess - Causes, Symptoms, Diagnosis And Treatment

Color blindness is a genetic condition that only rarely occurs in women, but affects one of every 10 men to some degree. When someone is color blind, it is usually because his or her eyes do not make all the pigments needed for color vision.  How is that? Please read on.



Think of your eye as a camera. The front of the eye contains a lens that focuses images on the inside of the back of the eye. This area, called the retina, is covered with special nerve cells that react to light.These retinal nerve cells include the rods and cones. The rods and cones react to light because they contain pigments that change when light strikes them. 

The cones are responsible for color vision. There are several kinds of pigments present in three types of cone cells. Some cones react to short-wavelength light, others react to medium wavelengths, and others react to higher wavelengths. 

There is only one kind of pigment in the rods, and it reacts the same way to any wavelength of light. The rods do not have anything to do with color vision; however, they are very sensitive to light and allow us to see at night. 

When the rods and all the types of cones are working together, the eye sees all possible colors. It is something like the way a painter can mix a few colors together and make paint of every possible color. 

If there is some problem with the pigments in the cones, the eye will not see colors in the usual way. This is called color deficiency or color blindness. 

If just one pigment is missing, the eye might have trouble seeing certain colors. Red-green color blindness – where red and green might look the same – is the most common form of color blindness, followed by blue-yellow color blindness. Patients who have blue-yellow color blindness almost always have red-green color blindness, too. 

Rarely, none of the pigments are present in the cones, so the eye does not see color at all. This most severe form of color blindness is known as achromatopsia. 
 

Does color blindness cause other health problems?

The kind of color blindness that is present at birth does not lead to additional vision loss or total blindness. But because the cone cells of the retina are also used to see fine details, people who are color blind tend to have vision that is less sharp. The rod cells also tend to be "overloaded" by bright light, so tinted eyeglasses often help color blind people to see better.
If you think you have a problem with color vision, you should schedule an appointment with an eye doctor right away. The doctor will be able to tell you whether you are seeing colors properly and what to do if you are not. 

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.
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:

• 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 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?

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 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 color blindness Treated?

Inherited color vision problems cannot be treated or corrected.

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.

You can find ways to help make up for a color vision problem, such as:

• Wearing colored contact lenses. These may help you see differences between colors. But these lenses don't provide normal color vision and can distort objects.
• Wearing glasses that block glare. People with color vision problems can see differences between colors better when there is less glare and brightness.
• Learning to look for cues like brightness or location, rather than colors. For example, you can learn the order of the three colored lights on a traffic signal.

sources : http://my.clevelandclinic.org/disorders
 
                 http://www.webmd.com/eye-healt
                 
                http://www.color-blindness.com/2007/10/24