When you were younger, your natural lens was both transparent and flexible.  Because of this, your vision was most likely stable until you reached your early to mid forties.  Around that time you may have noticed that you had to hold a menu or a book farther and farther away to read it.  Many people end up wearing reading glasses or bifocals to compensate for this aging of the eye.  This condition is called “presbyopia” and eventually affects everyone, including those who are nearsighted, farsighted, have cataracts or had perfect vision for most of their life.