Color Blind Eye Diagram. There are 2 types of blue yellow color blindness. The lines that are.
It was named after its designer shinobu ishihara a professor at the university of tokyo who first published his tests in 1917 the test consists of 38 colored plates each of which contains a circle of dots appearing randomized in color and size. To a person with one of these forms of colorblindness it can difficult or impossible to distinguish whether a given color is red or green and shades of red and green may have very low contrast. Its sometimes called being colour blind although total colour blindness an inability to see any colour is very rare.
Someone who is color blind is technically not blind to colors but may misidentify confuse fail to notice or notice colors less quickly than normal.
Being color blind i know that some are harder than others for me to see but cannot really tell you how people with normal color vision see them. Detailed color blind tests a screening test may be able to detect color blindness but a more detailed color blind test is needed to measure how severe the condition is. Click on image for more information and credits. The eye of the beholder.