You can change text size in the chat/whatever channel boxes (like he said.)
www.curseforge.com/wow/addons/leatrix-plus
Text Size
"Resize mail text - Resize text in the mail frame.
Resize quest text - Resize text in the quest detail frame."
Other general visibility stuff.
Found from this:
Something like this might help too:
https://www.wowinterface.com/downloads/info23335-AddOnFontManager.html
Not sure if that Leatrix one does it, but the default “Morpheus” font may be giving you trouble with that macular degeneration; Some other font are a lot more readable.
This contains info on step by step font replacement:
https://classic.wowhead.com/guides/changing-wow-text-font
In that article, here is an image of quest information after the default font for quests (morpheus?) was altered:
https://wow.zamimg.com/uploads/guide/images/18877.jpg
(can’t post images)
That may be useful information, since you can use a font which is by default “Large” (while some are more readable, as in that image example.)