After much discussion and investigation I have found it is possible to change the fonts in Outlook
Unfortunately it is a bit long winded but does work and for people with Eye Strain it can make those nasty headaches and migranes a thing of the past, so persevere with these fixes.
From the Main Inbox Screen :-
Click View –> Current View –> Customise Current View
Click Other Settings
Change all 3 fonts as required –> Click OK –> OK
Now to change the Navigation Pane (left hand side) do this outside of outlook,make sure you close Outlook then:
Click Start –> (Settings) –> Control Panel –> Display
Click Appearence –> Advanced
Change the Drop down next under Item: to “Menu” then select the required font type, size an color
Click OK –> OK –> Close Control Panel
Now re-open Outlook