History: The 100-year-old test for colour blindness

Did you know it was designed for military use?

If you’ve ever performed the ­Ishihara test for colour blindness, you’ll be familiar with the routine: you flick through page after page of colourfully concealed numbers while every so often throwing in the ‘nothing’ curveball, which your patient desperately tries to decipher like an inkblot at a psychiatrist’s office.

Ishihara's colour-blind test

But did you know that despite their deceptively modern appearance, the original dotty designs were hand-painted more than 100 years ago by an ophthalmologist during World War I?