Icon colors are difficult to see I changed a lot of items individually in the Edit>Preferences>Themes options to make it easier for my deteriorating vision. Somehow these changes made the icons for the toolbars on the right funny colors, vary pale with turquoise accent colors.

Nothing I set under the Icons section has that turquoise color, so the shading and color come from something else apparently. I have been reading that the icons are supposed to hard wired into the program and monochromatic, but something has changed them, somehow. Since I don't know what changed them and I can't find that turquoise color on any other items I set.

I did find I could set the background of the icon to black and then I could see them, but my vision does better seeing black items on white backgrounds so if there is any way to adapt these icons on the toolbar, I would like to know.
If you are talking about these icons:



You need to change the Themes>User Interface>Tab Inner, Selected and Outline colors.

Edit: OK, you mean these:



Unfortunately, those are built from source. See this link if you are interested in trying to modify them.

You can change the background and border though by going to User Preferences>Themes>User Interface>Tool and changing the Outline and Inner Options.