Color Blindness
Aravind Byju
Period 6
3/7/12
Color Blindness Color blindness is a sex-linked genetic disorder that affects many people. Approximately 8% of men and .5% of women are affected. Men are much more likely to be color blind because the cause is a mutation in the X chromosome, which females have two of. The recessive allele is Xb and is passed down from the parents. A male child would have to inherit Xb Y from their parents and a female would have to inherit Xb Xb. In the retina there are color sensing pigments or cones and rods. The rods give us our night vision and the cones distinguish colors. If one of these are missing or damaged then the person has trouble distinguishing between colors. The different colors of the spectrum each have different wave lengths. Someone with color blindness has problems with the coding instructions of pigments, therefore seeing different colors.
There are different variations of the disorder. The most common is Deuteranomaly or “Green Weakness”. People with this see colors shifted more toward red. The opposite is Protanomaly. In “Red Weakness” colors are more shifted toward green. Also loss of brightness or luminance is common. The rarest form of color blindness is Achromatopsia which only affects 1 in 30,000 people. In this uncommon condition all colors are perceived as grey. Many people have very mild cases of color blindness and don’t even know they have it. Most commonly a child parents will discover it at an early age. There are no physical symptoms with color blindness, but nystagmus, light sensitivity, lazy can be side effects in extreme cases. The disorder is diagnosed with the Color Vision or Ishihara Test. During the test the patient will be shown a card comprised of multicolored dots, and asked to identify a shape or number in it. Most people learn to cope with the disorder and end up living normal lives. There are special contact lenses to help the people afflicted distinguish between colors.
Period 6
3/7/12
Color Blindness Color blindness is a sex-linked genetic disorder that affects many people. Approximately 8% of men and .5% of women are affected. Men are much more likely to be color blind because the cause is a mutation in the X chromosome, which females have two of. The recessive allele is Xb and is passed down from the parents. A male child would have to inherit Xb Y from their parents and a female would have to inherit Xb Xb. In the retina there are color sensing pigments or cones and rods. The rods give us our night vision and the cones distinguish colors. If one of these are missing or damaged then the person has trouble distinguishing between colors. The different colors of the spectrum each have different wave lengths. Someone with color blindness has problems with the coding instructions of pigments, therefore seeing different colors.
There are different variations of the disorder. The most common is Deuteranomaly or “Green Weakness”. People with this see colors shifted more toward red. The opposite is Protanomaly. In “Red Weakness” colors are more shifted toward green. Also loss of brightness or luminance is common. The rarest form of color blindness is Achromatopsia which only affects 1 in 30,000 people. In this uncommon condition all colors are perceived as grey. Many people have very mild cases of color blindness and don’t even know they have it. Most commonly a child parents will discover it at an early age. There are no physical symptoms with color blindness, but nystagmus, light sensitivity, lazy can be side effects in extreme cases. The disorder is diagnosed with the Color Vision or Ishihara Test. During the test the patient will be shown a card comprised of multicolored dots, and asked to identify a shape or number in it. Most people learn to cope with the disorder and end up living normal lives. There are special contact lenses to help the people afflicted distinguish between colors.