I used the wrong figures here - I got the height of the screens wrong (used
width by mistake)! The correct screen sizes are:
19" screen - 12.4" high (aspect 4:3)
22" screen - 13.2" high (aspect 16:9)
This means pixels per inch:
19" screen - 82 pixels per inch (1024 verticle pixels)
22" screen - 77.5 pixels per inch (1050 verticle pixels)
This then means that text height per inch:
19" screen - font size 10 - 8.2 lines of text per inch
22" screen - font size 10 - 7.7 lines of text per inch - larger text, but
not a big difference
However, you didn't say what type of screens we are talking about, because
the above is based on a 19" LCD. If you are comparing with a 19" CRT, then
the vertical height is more likely to be around 10.7", which means 95 pixels
per inch and 9.5 lines of text per inch, so a 22" LCD replacing a 19" CRT
(using the stated resolutions) would result in larger text.
Your calculations are off, a typical 22" widescreen is not
actually 16:9 (1.77:1) ratio, it is 1680 / 1050 = 1.6 ratio
or 8:5
Also, just because a 22" monitor is advertised as 22", that
doesn't necessarily mean it actually is. Sometimes it's
really >= 21.5" rounded up to 22". Come to think of it, I
think this is true with most 22" monitors when they have the
same pixel pitch.
Manufacturers do spec dot pitch as smaller for a 22" than a
19" meaning slightly smaller text.
The pixel pitch of a 5:4 19" is typically 0.294mm
On a 22" it's typically 0.282mm
Taking 0.282 cm pitch * 1050 pixels vertical / 2.54 cm per
inch we end up with a 22" vertical size of 11.7". This must
not be entirely accurate either as I just measured my
1680x1050 22" (actual size 21.6") and it is spec'd by
manufacturer (and actually measures with a ruler) 11.4"
vertical viewable area size.
That makes the 19" monitors' text about 9% larger.
There are some other size options closer to 19" pixel pitch
but some of these are odd resolutions, and others are much
more expensive than a typical TN paneled 22".
For example these with 4:3 ratio but at an odd 1400 x 1050
resolution, IMO the resolution and screen size increase is
small enough it's hardly worth upgrading from a 19" 5:4.
http://www.newegg.com/Product/Product.aspx?Item=N82E16824016064
http://www.newegg.com/Product/Product.aspx?Item=N82E16824236026
A 28" with 1920x1200 would have even larger text but the
price jump is significant, and pixels that large tend to
look blocky unless the monitor is scooted further away to
the point where it might as well have been a smaller monitor
sitting closer to the user for the purposes of text size
(though of course it still has higher resolution so more
on-screen).
http://www.newegg.com/Product/Product.aspx?Item=N82E16824254026
The roughly 26" size group would also be a reasonable
alternative except the prices are still quite high relative
to the screen size.
IMO, if someone is looking for a budget priced LCD then 22"
is the best value at present. If the only goal were very
large text because of a sight impairment then it might also
be worth looking at LCD TVs.