Color-blindness resulting from insensitivity to red light, causing confusion of greens, reds, and yellows. It is hereditary and is the most common form of color-blindness.
- ‘The genetic cause has been determined for several color vision defects, achromatopsia (the loss of all color vision), blue monochromatism, protanopia, deuteranopia, and enhanced S-cone syndrome.’
- ‘Someone pointed out to us yesterday that the current things colour scheme is far from ideal if you suffer from protanopia, deutanopia or tritanopia - colour blindness.’
Early 20th century: from proto- original (red being regarded as the first component of color vision) + an- lacking + -opia.
We take a look at several popular, though confusing, punctuation marks.