The normal near point is defined as 25 cm , while the normal far point is at infinity. The corrective lens for far-sightedness creates an image at the person's actual far point for an object that is at infinity. In either case, the image is on the same side of the lens as the object. Hence the image is virtual and not inverted. The magnification is somewhat different from 1.00, which can make it difficult to get used to wearing glasses, as I can report first hand.
Physicists usually specify lenses by their focal lengths.
But especially in the eyeglass business, it is traditional to specify the strength of a lens in terms of the refractive power , which is measured in diopters , and which is defined as the inverse of the focal length, with the focal length measured in meters. Lenses with shorter focal lengths are stronger lenses, and have larger refractive power.