Younger users will balk at the advice I'm going to give.
I'm an older guy and my vision isn't what it used to be.
These days, I need LARGER text in order to discern individual characters.
A "retina" style screen doesn't help much, because sharper small characters do me no good -- they need to be LARGER, period.
OK, having said that...
You might consider a 27" 1080p display.
This will give you a pixel size of about .31mm at native resolution.
Younger folks will proclaim, "that's too GRAINY!!!"
But for my eyes, it's fine.
A list of displays that may be of use in your search:
Updated list of IPS monitors (also AHVA, PLS and other In-Plane Switching based tech) that offer the best color accuracy and wide viewing angles.
www.pchardwarehelp.com