For people who are farsighted, images come into focus behind the retina; for people who are nearsighted, images come into focus in front of the retina.
Prior to his invention around 1760, the convex and concave lenses (farsighted and nearsighted lenses respectively) were worn separately.
For example, one eye may be more nearsighted than the other eye, or one eye may be farsighted and the other eye nearsighted.
You can get them whether you're nearsighted, farsighted, need reading glasses, or have an astigmatism.
This usually occurs in children who are moderately to highly farsighted (hyperopic).
If you are farsighted your glasses will make your eyes look larger.
They reduce eye magnification for patients who are farsighted.
The North at first took arms simply to maintain the Union; but the farsighted politicians from the first, and soon the whole nation, saw that the real issue was the continued existence or the total abolition of slavery.
Valuable and farsighted as were these ideas, they fitted but ill into the scheme of a romance.