20/30 will not affect reading up close. It has a slight effect on reading a classroom board, and seeing clearly in the distance.
Yeah, a 20/30 should not affect reading at an arm's length.
Over here we don't use that system, but I see those numbers on the sides of the eye charts sometimes. I have a "425" prescription, which is very bad for someone my age. If I took off my glasses two feet away from the computer screen, I wouldn't be able to read the text on this page. I have bifocals, too, so I'm constantly asked "Aren't those the kinds of glasses that old people use?" x].
