We call this dichromacy, and people with this condition are considered color-blind, even though they can see most other colors.
我们称之为二色视觉，有这种情况的人被认为是色盲，尽管他们可以看到大多数其他颜色。
英语百科
Dichromacy
Dichromacy (di meaning "two" and chroma meaning "color") is the state of having two types of functioning color receptors, called cone cells, in the eyes. Organisms with dichromacy are called dichromats. Dichromats can match any color they see with a mixture of no more than two pure spectral lights. By comparison, trichromats require three pure spectral lights to match all colors that they can perceive, and tetrachromats require four.