No two pairs of eyes see alike, and for that matter, your own two eyes may not have the same vision. Refractive errors such as nearsightedness (myopia), farsightedness (hypermetropia) and astigmatism are all common vision problems, and often run in families. In addition, if you're over the age of 40, you may find you're beginning to need a pair of readers for up-close vision. This is an age-related vision problem called presbyopia (which is often confused with farsightedness because they have similar symptoms despite different causes). And that's just the beginning.
While it's common to wear corrective contact lenses for multi-focal correction (when you need help seeing at varying distances) such as bifocals, that doesn't mean you'll need to ditch your contacts and go back to glasses [source: American Academy of Ophthalmology]. Your average contact lens will correct a single problem, such as seeing things at a distance, but multi-focal contact lenses can provide what's called simulated simultaneous vision, which means they'll help you see far away and close-up, whether it's reading highway signs in the distance or your computer screen, as well as the small print on your tablet or smartphone. This type of lens may also, in the future, become the key to hands-free augmented reality: A wearer could simultaneously focus on her surroundings and incoming digital information from a Google Glass-type headset.