Color blindness A world of gray? Sarah Brubaker Color blindness A world of gray? Color Blindness: Is it really seeing a world of gray? Image acquired from: http://www.moondragon.org/health/disorders/eyecolorblindness.html

Discussion Points Key Vocabulary What is color blindness? Types Symptoms & Signs Causes Inheritance Prevention Tests Latest Research The table of contents is key vocabulary, what is color blindness?, types, symptoms & signs, causes, inheritance, prevention, tests, and latest research.

Key Vocabulary Cones: located in the retina of the eye; responsible for color vision and fine visual discrimination Color vision deficiency: inability to distinguish certain colors; when 1 or more cones are abnormal Trichromatic vision: normal vision with all three types of cones Photopigment: sensitive to a particular wavelength of light Some key vocabulary that is helpful in order to understand color blindness is color vision deficiency, which is the inability to distinguish certain colors; when 1 or more cones are abnormal. Trichromatic vision is normal vision with all three types of cones. Cones are located in the retina of the eye and are responsible for color vision and fine visual discrimination. Photopigment are in the cones and are sensitive to a particular wavelength of light.

Key Vocabulary (Continued) Retina: the tissue lining the back of the eye Red-green defect: loss of red or green cones; confuses reds with greens Blue-yellow defect: loss of blue cone; confuses blues with yellows The retina is the tissue lining the back of the eye. Red-green defect is the loss of the use of red or green cones and it is when the person confuses reds with greens. Blue-yellow defect is the loss of the use of a blue cone and it is when the person confuses blues with yellows.

Overview - What is color blindness? The inability to distinguish certain colors Misleading term Color blind people can actually see colors, they just get certain colors mixed up Different types: Red-green defect Inability to tell the difference between red and green Most common: 1 in every 12 men, 1 in every 200 women Blue-yellow defect Inability to tell the difference between blue and yellow Inherited Mostly men become color blind What is color blindness? Color blindness is the inability to distinguish certain colors. Color blindness is a misleading term because a person with color blindness can see color, they just get certain colors mixed up. There are many different types but the 2 most common are red-green deficiency and blue-yellow deficiency. Red-green defect is most common. 1 in every 12 men get it compared to 1 in every 200 women. Color blindness is usually inherited.

Types Protanopia and deuteranopia Tritanopia Achromatopsia Red-green color blindness Tritanopia Blue-yellow color blindness Achromatopsia Total color blindness Other words used to describe the types of color blindness are protanopia and deuteranopia, which are red-green color blindness. Tritanopia is another word for blue-yellow colorblindness and achromatopsia is total color blindness. Achromatopsia is very rare. Image acquired from: http://www.egeneralmedical.com/info-colorblind.html

Symptoms & Signs Inability to correctly identify colors People usually reach adolescence before their color blindness is identified The only symptoms and signs to identify color blindness is not being able to correctly identify colors. People usually reach adolescence before their color blindness is identified.

Causes Diseases Trauma Medications Alzheimer’s, diabetes, glaucoma, leukemia, liver diseases, multiple sclerosis, Parkinson’s disease, sickle cell anemia, retinitis pigmentosa Trauma Accidents or strokes Medications Medicines that are used to treat nervous disorders and psychological problems There are many causes for colorblindness. Some diseases such as alzheimer’s, diabetes, glaucoma, leukemia, liver diseases, multiple sclerosis, Parkinson’s disease, sickle cell anemia, retinitis pigmentosa can cause color vision deficiency. Trauma like accidents or strokes can be a factor as well. Medications used to treat nervous disorders or psychological problems are sometimes also the reason of color blindness.

Causes (Continued) Industrial toxins Aging Inherited Chemicals (Example: Carbon Monoxide) Aging After age 60, some people have trouble distinguishing colors Inherited More causes for color blindness are industrial toxins or chemicals such as carbon monoxide. Aging is also another cause for color blindness. After age 60, some people have trouble distinguishing colors because their eyes start to not work as well. And of course inheritance is the most common cause of color vision deficiency.

Inheritance Located on the X Chromosome Examples: Normal mother, color-blind father All children will have normal vision, but the girls will be carriers Carrier mother, normal father All the girls will have normal vision, but half will be carriers; half the boys will have normal vision and half will be color blind Carrier mother, color-blind father Half of the girls will be color-blind and half will be carriers; half the boys will be color-blind and half will have normal vision Very rare The gene for color-blindness is located on the X chromosome. If a mother with normal vision marries a color-blind father, then all the children will have normal vision, but the girls will be carriers. When a carrier mother and a color-blind father have children, all the girls will have normal vision, but half will be carriers and half the boys will have normal vision and half will be color blind. If children have a carrier mother and a color-blind father then half of the girls in the family will be color-blind and half will be carriers. Half of the boys will be color-blind and half will have normal vision. This condition for a family is very rare.

Inheritance (Continued) More likely for a boy to be color blind than a girl Girl: Inherits the gene for color blindness on both chromosomes which means she inherits it from both parents because a girl has two X chromosomes Boy: Inherits the gene for color blindness on one chromosome because a boy has one X chromosome and one Y chromosome which means he inherits it from only one parent It is more likely for a boy to be color blind than a girl because a girl inherits the gene for color blindness on both chromosomes which means she inherits it from both parents because a girl has two X chromosomes. A boy inherits the gene for color blindness on one chromosome because a boy has one X chromosome and one Y chromosome which means he inherits it from only one parent.

Prevention of color blindness Color blindness cannot be prevented Depending on the cause of color blindness, it might improve over time When inherited, it is permanent and will remain constant Color blindness cannot be prevented. Depending on the cause of color blindness, it might improve over time. When it is inherited, it is permanent and remain constant.

Tests Ishihara test American Optical/Hardy, Rand, and Ritter Several disks with many different colored dots with a number or shape partially hidden American Optical/Hardy, Rand, and Ritter Different colored blobs with a hidden number Titmus II Vision Tester Color Perception Designs or numbers on a black background framed in a yellow border Not very accurate There are three tests that are used to identify color blindness. The Ishihara test is the most common and uses several disks with many different colored dots with a number or shape partially hidden because the dots are similar colors. Depending on what type of color blindness is being tested, the dots are different colors. The American Optical/Hardy, Rand, and Ritter is another test using blobs instead of dots like the Ishihara test. Titmus II Vision Tester Color Perception is not used very much because it is not very accurate. This test consists of designs or numbers on a black background framed in a yellow border.

Test 1 – What do you see? You should see a 2. Here is a test used to determine if one is color blind. What do you see? You should see a 2. If you cannot see it, you may be color blind. You should see a 2. Image acquired from: http://colorvisiontesting.com/ishihara.htm

Test 2 – What do you see? You should see a 7. Here is another test. This time you should see a 7. You should see a 7. Image acquired from: http://colorvisiontesting.com/ishihara.htm

Interesting Facts Percentages in the U.S.A. Ratios 7% of the male population is color blind 0.4% of the female population is color blind Ratios 1 in 10,000 people worldwide are color blind 1 in 30,000 people have achromatopsia (total color blindness) About 7% of the male population is color blind and 0.4% of the female population is color blind in the United States. 1 in 10,000 people worldwide are color blind and 1 in 30,000 people have achromatopsia, which it total color blindness.

Works Cited Ballard, Carol. Eyes: Injury, Illness and Health. Chicago: Heinemann Library, 2003. Print. Carroll, Joseph. “Color blindness.” World Book Student. World Book, 2014. Web. 25 Apr.2014. Fallon, Jr., L. Fleming. “Color blindness.” The Gale Encyclopedia of Genetic Disorders. (2010): 1-3. Science in Context. Web. 29 Apr. 2014. Steffel, Loraine T., and Timothy E. Moore. “Color Blindness.” The Gale Encyclopedia of Nursing and Allied Health 2 (2013): 816-818. Gale Virtual Reference Library. Web. 6 May, 2014