Repairing Mirrored Cabinet Doors?

The mirrored doors on my medicine cabinet in the bathroom are beginning to lose the mirror on the edges of the beveled doors and are looking rather worn. I would like to be able to fix them if I can as I haven't been able to find anything I like as much.

It's a triple mirror with the middle recessed and two smaller width mirrored doors on each side for storage. We bought it at Home Depot about eight or nine years ago. They have never had anything like it again although we continue to look every time we're there.

Kathryn from Virginia