"My old eyes can't read the small type on the FileMaker screen. Is there a solution?"
It is possible to manually zoom the screen even larger for the occasional screen by clicking the small 'mountain' icon in the bottom left of the FileMaker window. Click the 'grow' mountain repeatedly to keep zooming. Click the 'shrink' mountain icon to return to a smaller screen view.
Of course, if your programmer has been thoughtful, he may have programmed this into the system to set the zoom level as a default. This can be done either at the global level or at the user level.
Change the Zoom Level from 100% to 150% to have a consistently larger view of the database. Now, whenever you change layouts, the zoom level will be adjusted.