Ishihara colour blindness test, London, England, 1948
Used to test for colour blindness, this test is named after its inventor, Shinobu Ishihara (1897–1963), a Japanese ophthalmologist. Each image is made up of a series of closely packed coloured dots and includes a number. The patient is asked to identify the number or image that they can see. By using the range of charts, the type of colour blindness a patient has can be identified. There are three types of colour blindness: daltonism – inability to distinguish reds from greens (the most common type); monochromatism –where all colours appear as shades of one colour; and total colour-blindness. Ishihara devised his test in 1917 and is still used today.
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The branch of medicine dealing with the diseases and surgery of the visual pathways (usually the eyes or the brain).
A written or printed work consisting of pages glued or sewn together along one side and bound in covers. Usually continuous printing or writing.
Glossary: colour blindness test
A test to find whether a person is colour blind. The most commonly used test in the world is the Ishihara test invented in 1917, where numbers are concealed within a circle of different colours.