I downloaded Microsoft Office in January of 2014. Both ribbon bar and text in documents very fuzzy and retina display clearly NOT supported by microsoft office.
I'm now updated to version 14.3.9 of microsoft office and the retina display is now working for all office applications.
That is the fix, but ...
Clearly ridiculous that I can download microsoft office, direct from microsoft, and it needs to be updated before it works properly ! Obviously any download from a major software company should always be the latest version.
If you are having problems with retina in microsoft office, solution is to click 'update'