GARMIN GPSMap76 (no color) screen deterioration

GARMIN GPSMap76 screen contrast fading: The screen on my Garmin Map76 becomes harder to read - there is no longer a crisp contrast between the light and dark areas / words. It looks like the screen is degrading.

Is this normal and is there something that can be done to restore it without major expense ?

I had suggestions that one could replace the polarizing foil, but have no idea if that applies to this GPS and if that would be easy to do.