Vision Information - Color Vision Deficiency
Color blindness is the popular term used to describe color vision deficiency, which is the inability to distinguish certain shades of color. In some severe cases patients are unable to see colors at all, but very few people are completely color blind.
Most people with color vision deficiency can see colors, but they have difficulty distinguishing between them. Differentiating particular shades of reds and greens is the most common, with blues and yellows less common. It does not mean that people with a red-green deficiency cannot see the colors red or green, but simply that they find it difficult to distinguish between them. The difficulty they have in differentiating them will depend on how dark or light the colors are.
The blue-yellow deficiency is a less common but more severe form of color vision loss than red-green, since patients with blue-yellow deficiency frequently have red-green blindness too.
People who are able to see things only as black and white, or in shades of grey, are completely color blind and suffer from a condition called achromatopsia.
The degree of color vision deficiency can range from mild to severe depending on the cause. Both eyes will be affected if the condition is inherited and usually only one if the cause is due to injury or illness.
What Causes Color Vision Deficiency?
Color vision deficiency is most often an inherited condition caused by a common X-linked recessive gene. But disease or injury that damages the optic nerve or retina can also cause color vision deficiency. Some diseases that can cause color vision deficiency are:
Some drug medications that are used to treat heart conditions, nervous disorders, infections, heart conditions and psychological problems can also influence color vision.
The ability to see colors can lessen with age and contact with certain chemicals such as fertilizers and styrene may also cause loss of color vision.
But genetics is the predominant cause of color vision deficiency and around 8% of Caucasian males are born with some degree of color deficiency. Women are usually just carriers of the recessive gene, though about 0.5% of women have color vision deficiency. It is important for color vision deficiency patients to remember that the inherited condition does not lead to additional vision loss or blindness.
How is Color Vision Deficiency Diagnosed?
A comprehensive eye examination by your eye care practitioner is needed to diagnose color vision deficiency. The test will include a series of specially designed drawings composed of colored dots called pseudisochromatic plates, which include hidden numbers or embedded figures that can only be properly seen by persons with normal color vision.
Treatment of Color Vision Deficiency
Inherited color vision deficiency cannot be cured. But if the cause is due to illness or eye injury, treating the latter conditions may improve color vision.
Most persons with color vision deficiency compensate for their inability with color cues and details not consciously evident to people with normal color vision. Here are some ways to get around the problem:
Although color vision deficiency can be frustrating and limit participation in some occupations and social activities, it is not a serious threat to vision and with a little patience and practice can be comfortably integrated into your lifestyle over time.