|What kind of monitor?|
Possibly the monitor's OSD (on screen display) will have a focus adjustment. If not and if it's an older CRT monitor there's a focus adjustment on the flyback transformer inside the monitor. It's not a good idea to mess with that on your own cause if you touch the wrong thing with your bare pinky it could kill you. But a shop should be able to make the adjustment.
If the monitor is an LCD check its manual to see how to adjust the focus.
The mantra of the aging hippie--"Power to the government, right on"