Jay and Maureen Neitz explain it on their website as follows: Before the treatment the monkeys had only two perception patterns which could differentiate hues, S supported by M and M supported by S. The insertion of the third opsin gene gave rise ... more

Actually I really don’t know. But I fear that most of the time they only have some Ishihara plates to test colorblind persons. For proper testing you also would need some other tests like an University test for blue-yellow color blindness and of ... more

In this case you can compare it with near- or farsightedness. Some people have it, some not. Most people get farsighted when they get older but most important of all, it never causes pain. This is just what and how you can see, but it can never be ... more

Most color vision problems are inherited (genetic) and are present at birth. Other color vision problems are caused by aging, disease, injury to the eye (acquired color vision problems), optic nerve problems, or side effects of some medicines. ... more

Color blindness, more accurately called color deficiency, is a term used for a deficiency in recognizing certain colors. Most color perception defects are for red or green or both. Another form of color blindness; yellow-blue is the second most ... more