Partial color blindness is due to a defect of the retina which makes it unable to be affected by light waves producing red and green.
"The Science of Human Nature" by William Henry Pyle
DALTONISM, the commonest form of color-blindness in which the affected individual is unable to discriminate between red and green.
"Being Well-Born" by Michael F. Guyer
If you can't see the numeral 2, you may have red-green color blindness .
If you can't see the numeral 6, you may have red-green color blindness .
If you can't see the numeral 5, you may have red-green color blindness .
After receiving injections of genes that produce color-detecting proteins, two color-blind monkeys have seen red and green for the first time.
Eight percent of men experience red-green color blindness, which results from mutations in genes that code for light-sensitive pigments.