Around 8 percent of men and 0.5 percent of women suffer from an inability or reduced ability to see color or a difference between colors in normal light conditions. It can be total or partial, acquired or inherited.
There are several types, and while this is not a section that goes into a lot of detail, it is worth considering. Two percent of men have difficulties telling the differences between red, orange, yellow, and green. That being the case, the following screenshot might not be a good decision for your audience:
The following are a few reference sites for further reading: