Color blindness is the inability to see or differentiate color under normal lighting conditions.
Color blindness can be inherited or acquired.
There are 3 known types of inherited color vision deficiencies such as anomalous trichromacy, dichromacy and monochromacy.
By acquired we mean that it can appear because of some damage to the eye, parts of the brain or the optic nerve. It can be done by physical damage or chemical damage.
This disability can cause problems in one’s search for a job occupation where color perception is essential, jobs occupations like electricians who uses color coded wires or drivers who have to follow color coded signals.
Ishihara test is a test performed by physicians in order to diagnose color perception deficiencies or color blindness. The test is named after the scientist Dr. Shinobu Ishihara who published his test for the first time in 1917.
Ishihara test consists of 24 to 38 colored plates. Each of these plates contains of the circle filled with dots in different sizes and colors. Some of these plates have visible pattern within the circles and some don’t. People with no color deficiency should be able to notice the pattern or see no patterns at all when required. All the plates are designed to reveal problems with color perception. Problems like red-green color vision defect or blue-yellow color vision defect. The test can reveal problems even after seeing only a few of these plates.
This test consists of plates that have visible and recognizable patterns or plates with hidden digits that can be recognized only by people with color perception defects. Some of these plates are specifically designed to determine the defect.
Below you can find the test and instructions on what to do.