[rkangel]

There's two different things - the stuff you get at birth and the stuff you get as you get older.

Short sightedness (myopia), long sightedness (hyperopia) and astigmatism are effectively genetic conditions that you are born with. They are variations of your eye being slightly the wrong shape to focus correctly. The precise impact of this varies as you grow with your prescription changing, but if you need correction then you'll need it from a young age onwards (unless you have it permanently treated - e.g. Lasik, or cataract surgery).

Presbyopia is an effect that happens over time. The lens hardens and so the muscles that manipulate it to refocus can't quite do the job any more. This impacts on your ability to close distances, and so you can off the shelf reading glasses to aid in that.