Tuesday, April 22, 2008
Friday, April 18, 2008
Info
- Color blindness is the inability to distinguish certain colors from other colors. Color blindness is not a form of blindness at all, but a deficiency in the way you see color.
- Color blindness occurs when cone cells in the retina that normally respond to color do not respond as they should. In most color blind cases, the person has a different mixture of cones. The cone cells on the retina are the crucial physical components in seeing color. Every person has three cones, the Long wavelength (red), Medium wavelength (green), and the Short wavelength (blue), also grouped together as the L-,M-, and S- cones. Color blindness results when one or more of these cones has a defect. This is what causes color blindness genetically. You may also acquire color blindness for natural reasons, such as a car accident or cataracts.
- To diagnose color blindness, tests are used to measure the ability to recognize different colors. The most common test is the pseudoisochromatic plate test. In this test, you are asked to look at an arrangement of colored dots and identify a pattern, such as a letter or number. The type of color vision problem you have can often be determined by which patterns you can and can't see in the various plates used for the test. For people with acquired color vision problems, an arrangement test is used. This test involves arranging colored chips in sequence according to color from a reference color.
- Symptoms vary in color blindness from person to person. Most people just have trouble seeing different colors separated from one another. Others have no idea of how bright or dark a color is. Sometimes, the symptoms are so mild that the person doesn't even realize they're color blind. In the worst case scenario, your eyes make rapid, side-to-side movements. You would not be able to see any color except for black, white, and gray.
- Color blindness has no medical cure. Treating color blindness early is important, as it may help prevent learning problems during the school years. Color blindness that is acquired, such as the color blindness from my previous cataract example, may be improved by eye surgery. Another very common remedy for color deficiency is sunglasses and/or specially-tinted contact lenses. These may help you to see differences between color. However, the vision still is not normal and may distort objects. All in all, color vision problems will always stick with you.
- Prognosis: Color blindness is a life-long condition. Color blindness that is inherited is present in both your eyes and remains constant over your entire life. Some cases of acquired color vision loss are not harsh and last for only an abrupt time. Other cases tend to be progressive, becoming worse with time. Color blindness cannot kill you.
EXTRA INFORMATION
-Color blindness is commonly found in males (one in twelve), and infrequently in females (about two percent).
-There are three types of congenital color blindness: Monochromacy (total color blindness), Rod monochromacy (no cones in retina), and Dichromacy (moderate severity).
-Red-green color blindness is the most common, followed by blue-yellow color blindness.
-This condition is rare among people of Asian, First Nations, or African descent.
-The rat is the only mammal that perceives the world only in the color of gray.
-Color blind people see better in low light situations than brighter situations.
-All babies are color blind when they are born.
-Dogs are color-limited, not color blind.
- Color blindness occurs when cone cells in the retina that normally respond to color do not respond as they should. In most color blind cases, the person has a different mixture of cones. The cone cells on the retina are the crucial physical components in seeing color. Every person has three cones, the Long wavelength (red), Medium wavelength (green), and the Short wavelength (blue), also grouped together as the L-,M-, and S- cones. Color blindness results when one or more of these cones has a defect. This is what causes color blindness genetically. You may also acquire color blindness for natural reasons, such as a car accident or cataracts.
- To diagnose color blindness, tests are used to measure the ability to recognize different colors. The most common test is the pseudoisochromatic plate test. In this test, you are asked to look at an arrangement of colored dots and identify a pattern, such as a letter or number. The type of color vision problem you have can often be determined by which patterns you can and can't see in the various plates used for the test. For people with acquired color vision problems, an arrangement test is used. This test involves arranging colored chips in sequence according to color from a reference color.
- Symptoms vary in color blindness from person to person. Most people just have trouble seeing different colors separated from one another. Others have no idea of how bright or dark a color is. Sometimes, the symptoms are so mild that the person doesn't even realize they're color blind. In the worst case scenario, your eyes make rapid, side-to-side movements. You would not be able to see any color except for black, white, and gray.
- Color blindness has no medical cure. Treating color blindness early is important, as it may help prevent learning problems during the school years. Color blindness that is acquired, such as the color blindness from my previous cataract example, may be improved by eye surgery. Another very common remedy for color deficiency is sunglasses and/or specially-tinted contact lenses. These may help you to see differences between color. However, the vision still is not normal and may distort objects. All in all, color vision problems will always stick with you.
- Prognosis: Color blindness is a life-long condition. Color blindness that is inherited is present in both your eyes and remains constant over your entire life. Some cases of acquired color vision loss are not harsh and last for only an abrupt time. Other cases tend to be progressive, becoming worse with time. Color blindness cannot kill you.
EXTRA INFORMATION
-Color blindness is commonly found in males (one in twelve), and infrequently in females (about two percent).
-There are three types of congenital color blindness: Monochromacy (total color blindness), Rod monochromacy (no cones in retina), and Dichromacy (moderate severity).
-Red-green color blindness is the most common, followed by blue-yellow color blindness.
-This condition is rare among people of Asian, First Nations, or African descent.
-The rat is the only mammal that perceives the world only in the color of gray.
-Color blind people see better in low light situations than brighter situations.
-All babies are color blind when they are born.
-Dogs are color-limited, not color blind.
Traffic Light
The above photo shows a regular traffic light on the left in which non-color blind people see. The traffic light on the right shows what color blind people may see.
Wednesday, April 16, 2008
The Test
The picture at the right shows four different pictures with different colors that allow anyone to take a color blind test. They are made of dot patterns composed of primary colors. These dot patterns represent a symbol that is layered on a background of randomly mixed colors. The test can determine certain abnormalities in a person's color vision.
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