Colour blindness test. Plate 1 of an Ishihara test. Invented by Japanese physician Dr Shinobu Ishihara in 1917,the charts use arrangements of coloured dots to test for red-green colour blindness. The 12 in this first plate will be able to be seen by those with normal vision and those with colour blindness and is used to explain the test to subjects. The full test comprises 38 plates that test the type and severity of deficient colour vision. Colour blindness is usually caused by an inherited genetic defect in the light-sensitive cells (cones) of the eye. Colour blindness can also be caused by optic injury or nerve diseases | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library |
Bildgröße: | 4193 px × 4193 px |
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