Font size in apple mail too small

Is there a way, an app, or an add-on to make the size of the text in apple mail larger, i.e., easier to see without changing the font size? Does apple supply binoculars or magnifying glasses to make the text easier to see, like "magic binocs for mail"?

Of course, I can increase the text size of incoming messages, but I have to this repeatedly, but changing the font size in the composer window requires changing it back to an acceptable 12-13 size font before sending.

Apple hardware is really great, the IOS is excellent, other apple software is nice, but apple mail dramatically increases my consumption of headache pills or trips to the optometrist. (I would prefer to not use other apps....)

Any suggestions?