Three quarters of Americans need corrective lenses at some point in their lives, but very few ever stop to consider what it takes to correct vision. Blurred vision comes from several different root causes, the majority of which have to do with a misshapen portion of your eye. When light waves hit your misshapen eye it causes them to fall well short or long of the focal point, and corrective lenses can change that by refracting the light to hit where it should.

Corrective lenses have been around for hundreds of years, so the science behind vision correction isn’t always our first thought when we visit an ophthalmologist. Myopia is caused by light coming into focus before it reaches the focal point, causing distant objects to look blurry, while hyperopia is caused by light waves that never make it into focus, making close objects appear blurry. Both of these conditions can easily be corrected with the proper lens curve in a pair of glasses. Learn more about how glasses work from this infographic!