اختبر صحة رؤيتك للالوان عن طريق اختبار عمى الالوان عبر البحث عن اختبار عمى الالوان eviewed by Dr. Michael Fu INSIDE THIS ARTICLE: What is Color Blindness? Color Blindness Symptoms What Causes Color Blindness? Types of Color Blindness Color Blindness Test Viewing the World with Color Blindness Color Blindness Treatment Prognosis for Color Blindness Talking to Your Eye Doctor SEE ALSO: Healthy Eyes Eye Drops Color Blindness Did you know one in eight boys are color blind, while only one in thirty girls are color blind? Read on to learn more about this condition and take our color blind tests. What is Color Blindness? Color Blindness, or Color Deficiency, is an eye condition that causes an inability to distinguish certain colors or shades of colors to some degree. Color blindness does not mean that a person can only see black and white. A person with color blindness is able to see different colors, but they are not able to distinguish some colors from others due to deficiencies in the eyes. Color blindness is a hereditary condition, but it can also be caused by eye diseases, damage to the retina and macula, aging, or cataracts. Although there is no real treatment for hereditary color blindness, there are ways to cope with it. For example, there are special glasses that can help people with color blindness distinguish between different colors, even if they cannot truly see them. If you have trouble seeing the numbers in one of the pictures below or are not able to see them at all, then you may have some degree of color blindness. Color blindness test Color blindness test Color Blindness Symptoms Symptoms of color blindness vary from person to person. Many people who are color blind have trouble seeing how bright colors appear to be. Other people are unable to tell the difference between similar colors. Many experts believe symptoms of color blindness may be so mild in some people that they are unaware of their condition. Parents may notice that their child is color blind based on the child’s performance in certain learning activities. What causes Color Blindness? The retina contains rods and cones that help us to see objects in different colors and varying degrees of brightness. The cones are photoreceptors that allow us to distinguish among colors and different shades of these colors. The cones contain light-sensitive pigments that are particular to a range of wavelengths. There are three different types of cones, one of which is sensitive to short wavelengths, or the color blue, one sensitive to medium wavelengths, or the color green, and the other sensitive to longer wavelengths, or the color red. When the cones are unable to distinguish differences among these wavelengths, we see that color range differently. The absence of the cones responsible for green and red hues can also affect sensitivity to brightness. Red-green color blindness is more common than blue or yellow color blindness. Color blindness is usually hereditary, meaning that we are born with it. Age can also diminish our color sensitivity, but usually not to the extent that occurs with hereditary color blindness. Damage to the retina from eye diseases or injury may also lead to color blindness. Common eye diseases that may affect color vision include: Cataracts Diabetes Leber’s hereditary optic neuropathy Macular degeneration Parkinson’s disease Retinoblastoma (seen in children) Occasionally, medications may affect one’s color vision. Common medications known to do this include: Myambutol Ibuprofen Naproxen Estradiol Oral contraceptives Digitalis Hydroxychloroquine (Plaquenil) Chloroquine Types of Color Blindness Anomalous Trichromacy: A mild shift in the sensitivity of the cones Protanomaly: shades of red appear weaker in depth and brightness Deuteranomaly: shades of green appear weaker Tritanomaly: very rare cases in which shades of blue appear weaker Dichromacy: Severe deficiency or complete absence of one of the types of cones Protanopia: shades of red are greatly reduced in depth and brightness, if they can be seen at all Deuteranopia: shades of green are greatly reduced in depth and brightness, if they can be seen at all Tritanopia: very rare cases where shades of blue are greatly reduced in depth and brightness, if they can be seen at all Color Blindness Test There are a few methods for color blindness testing. The most used is the Ishihara test. This test involves the use of pictures containing circles filled with bubbles in shades of the colors to be tested. The bubbles form the shapes of numbers that color blind people will not be able to distinguish. Samples of these plates are pictured above in the “Types of Color Blindness” section of this page. A more complex test is the Farnsworth-Munsell 100 hue test, in which a person must place numerous colored tiles of varying hues in order. To take a color blindness test, please visit: colorvisiontesting and iamcal/toys/colors/index.php Viewing the World with Color Blindness Normal View Normal View
Posted on: Wed, 23 Oct 2013 11:12:05 +0000
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