If you are having a problem with vision that is getting kind of poor, you may benefit from a change to the way Windows displays on your screen. It is a high contrast setting that kind of reverses so that white is on black instead of the usual black on white.
It is easy, really. Hold down both the Shift and Alt keys, then press the key on the top row labeled Print Screen. You can toggle back to the usual view by pressing the same key combination again.