Wearing glasses doesn't reduce the need or desire for higher resolution monitors. Maybe uncorrectable vision problems do, but if your glasses get your eyes close to 20/20, you'll benefit from higher resolution just like people with natural 20/20 vision.
And as another poster pointed out, the blurriness of the screen may compound with the natural blurriness of uncorrectable vision loss.
Depends on the usage I guess.
The larger the screen, the further away you stand.
I have a 2560x1440 32" monitor with a <100dpi. It's great for text editing (I use a bitmap font). For other use, I would love 5k :)