What Does My Child With A Color Vision Deficiency See?

• October 26th, 2010
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• Filed under: color vision

What does my child with a color vision deficiency see?

Color vision deficiencies can be congenital or acquired. There are acquired color vision deficiencies that can occur later in life from conditions that affect the lens, retina, or optic nerve in the eye. I am going to talk about the color deficiencies that are congenital in nature—the type that a person is born with.

The inherited nature of color vision deficiencies causes these to run in families. The gene for the color vision abnormality is found on the X chromosome. It is recessive, which means that when combined with a normal X chromosome the person has normal color vision. Females have two X chromosomes. This is why congenital color vision defects are estimated at less than 1 % of females. Males have one X and one Y chromosome. Approximately 8 % of males are affected by a color vision deficiency. Oftentimes, a little boy’s mother is not affected, but her father and/or brothers may have a color vision deficiency. Two boys from the same parents can be affected differently; in other words, one may have normal color vision while the other has a color vision deficiency.

Congenital color vision deficiencies do not change over time. A baby born with it will always be affected by it. The good news is: that baby will easily adapt to how he perceives colors. Identifying a color vision defect early can have a positive impact on a child’s education. By knowing that a child does not differentiate colors normally, a teacher and parent will be able to ensure that child is not graded based on color.

Color is perceived by structures called cones, which are a part of the retina. There are cones responsible for seeing red, green, and blue. Color vision deficiencies occur in different degrees. Some people’s color perception is only mildly affected, while other people’s perception is more severely affected. For example, in a person with a more severe defect the red cones may be missing or may not function at all while a person with a mild defect may have red cones that almost function normally. This makes it difficult to describe what a person with a color deficiency sees. I’ve attempted to simulate three common color deficiencies. The red/green deficiencies are much more common, while the blue/yellow deficiencies are rare.