Scarlet LetterEssay title: Scarlet LetterA common misconception of people is that being color-blind means that you can only see shades of gray, black, and white. But total color blindness is extremely rare, and virtually no one is truly color blind. More typically, is partial color blindness which is called color vision deficiency, a condition in which certain colors cannot be distinguished.
Color blindness may be a hereditary condition or caused by a disease of the optic nerve or retina. Acquired color vision problems only affect the eye with the disease and may become progressively worse over time. People with a color vision defect caused by disease usually have trouble distinguishing blue from yellow. However, inherited color blindness is most common; it affects both eyes, and does not worsen over time. People with inherited color blindness have more difficulties distinguishing red from green. This type is found in about 8% of males and 0.4% of females. Since men only have one X chromosome, the chances of color blindness showing up in men are much higher than in women, who have two X chromosomes so color blindness is almost always passed on from a mother to her son.
Determination of the Cause of color blindness: î €
If your child starts with inherited color blindness and is completely color blind, it is possible that his or her parents are either suffering from a different trait, such as a rare disorder or an inherited disease, or both may have the same cause. All children and adults who are completely color blind do not always show any signs of color blindness — they may still have a low average IQ, but their vision and hearing may still fail, despite having the same eyesight. A rare disorder of the optic nerve or retina, genetic and environmental factors such as a history of physical or environmental complications will also play a role. Parents who develop the condition may never see their child fully colorblind, and they may be unaware of his or her true condition.
The Genetics of Color Blindness
In a recent study of adults with a genetic predisposition to visual color blind, a large majority of children showed behavioral and neurologic impairment in the first six months, but by the middle year, most parents with the most severe disorder had no significant learning disabilities at all. There were no significant behavioral deficits in children with the more severe disorder, but the same pattern of behavioral deficits persisted in children with the more severe phenotype (Table 1).
The Genetics of Color Blindness In order to learn to live with color blindness, a child must develop a set of behavioral and neurological rules and rules that help him or her perceive both the color gray and yellow, the most colorful colors, and the simplest colors. These rules and rules are based on a combination of what color blind people know (e.g., their color sense comes from looking at objects that are not on their face), and what colors people see. In children with color blindness and their parents who did not develop the genetic condition, this color blind personality development does not occur. This character is defined as “distant visual perception, a person’s perceptions of two or more colors in color in an unrelated way, a person’s vision perception of two or more colors in an unrelated way, or a person’s color perception of multiple colors in color…” A child with color blindness does not have the same ability to distinguish red, green, yellow, or white from blue, yellow, or white, but they have the same intelligence. There are some genetic aspects of color blindness that may predispose the children to such differences. These genetic factors may have been the main causes for several of the common “blind spots” in color blindness. However, some of these genes may have had greater influence on color vision than others. Therefore, it is important that the genetics of color blindness be assessed first and foremost to determine if genetics could help or hinder this development. Genetic risk factors include:
Differences in the genes involved in the genetics of color blindness have been shown to be more important than genetics in the cause of color blindness in some genetic studies. This can occur when parents are shown children with color blindness with other genetic disorders.
If any of these genes cause child vision impairment, that is if they influence any individual’s vision.
All genetic susceptibility to
There are three groups of inherited color vision defects; anomalous trichromacy, dichromacy, and rod monochromacy.Anomalous Trichromacy is the least severe of the three, and is by far the most common form of color blindness. It occurs in about one to five percent of males. Anomalous Trichromacy is caused by a shift in the sensitivity of one or more cone types. It reduces the ability to discriminate between colors but it does not eliminate color perception all together. Anomalous Trichromacy is divided into three subgroups; protanomaly, deuteranomaly, and tritanomaly. Protanomaly and deuteranomaly are both forms of red/green color deficit, and they are both usually inherited. The conditions Protanomaly and deuteranomoly are caused by the lack of “green cones” in the eye’s retina. The last form, tritanomaly is a blue/yellow color deficit, and is usually acquired. Tritanomaly is caused by the lack of blue cones in the retina.
Dichromacy is a more severe form of color vision deficiency. Dichromats lack one of the three cone types entirely, but can still tell some hues apart. Like anomalous trichromacy, dichromacy is also divided into three subgroups; protanopia, deuteranopia, and tritanopia. Protanopia is similar to protanomaly but is more harsh. Protanopia is one of the forms of red/green color deficit. The other form of red/green color deficit in dichromacy is deuteranopia which is similar to deuteranomoly, but again, more harsh. Lastly, there is tritanopia, which is a form of color blindness that prevents the person with that condition to be able to differentiate the colors blue and yellow.
Finally there is rod monochromacy, which refers to people who are truly color blind because they cannot distinguish any colors whatsoever. They only see different degrees of lightness. For them, the world appears to be in shades of gray, black and white. They also have poor visual acuity, aversion to bright light and often have nystagmus (an involuntary, rapid movement of the eyes.) To have rod monochromacy, someone must inherit a gene for the disorder from both parents. Only one in 30, 000 people have rod monochromacy.
Our eyes can see color when light stimulates the retina (a neuro membrane lining the inside back of the eye.) Covering the retina are millions of light sensitive cells called rods and cones. The cones pick up color and the rods control brightness. Nearly everyone has red, green, and blue cones which are sensitive to those colors and combinations. Color vision occurs within the visual part of the brain where the brain compares electrical signals from the different types of cones. The human eye and brain work together to translate light into color. People