What is Color Blindness
Color blindness is lack of color vision so when a person can't distinguish some colors. It does not necessarily mean seeing only black and white (also called monochromacy = total color blindness). Some people can't simply recognize one certain color. For instance, they don't know the difference between red and green. That's why most "colorblind" people can actually see many colors, however, they can't tell a few specific ones.
Our eyes have three color receptors - red, green and blue. That's why our color vision issues are naturally based on those 3 colors and their mixtures. The following pictures depict what the color blind see when they look at colors of rainbow.
How Do You Get Color Blind
Color vision deficiencies can be acquired (eg. by accidents), however, they are usually inherited. Approximately 8% of men and 0.5% of women are color blind. So the chances are quite high that you know some color blind men. Most people have problems to tell green color from red.
Color Blindness Tests
Color Blindness Tests, also called "Ishihara Color Test", are eye exams commonly used by optometrists and eye doctors which can determine defect of red-green color vision. You are presented with a few colored plates each containing colored dots. Your task is to identify a pattern (eg. number or letter) made out of the dots.
1st Color Blindness Test
Can you see a "12" on this plate?
2nd Color Blindness Test
There is a "26" on this plate.
3rd Color Blindness Test
Can you trace a line from one "X" to the other?
4th Color Blindness Test
You should see 58 (upper left), 18 (upper right), E (lower left) and 17 (lower right).
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