Green on yellow as seen by people without color blindness and by those with three different types of color blindness.
About eight percent of men and 0.5 percent of women have some form of color blindness. That means that potentially 1 in 12 readers of your document may not distinguish the colors you designed. Color blindness does not mean that people cannot see color, or that they see only in black and white. It is more that they have a reduced spectrum of colors they can distinguish between.
Do not rely upon your color choices being displayed correctly with your documents. A person might have their computer display set up with colors that are good for them.
Since there are three types of color blindness, there are no simple choices of colors that you can safely use. As you can see from the picture on the left, the bright green "T" might be indistinguishable against some of the color backgrounds, but the dark green "T" is much more visible. Therefore, the best thing to do is to rely upon a sharp contrast between your colors.
The greater the contrast, the easier it will be to read the text. Plain black text on white is the easiest of all to read as it has the greatest contrast.
Remember our golden rule for accessible documents and do not rely upon color only to convey information. It is useless to tell a person who can't see colors to press the red button, without indicating that button in some other way.