A 1970 Corvette

Well y'see Slick, light has to be refracted through your eyeball to hit your retina. But some people's eyeballs are a little too long or short, and the light hits the retina before or after the image becomes clear. So we put pieces of glass in front of our eyes to compensate for this error. Since no two people's eyes are the same, everyone needs a different prescription. That's why one person's glasses can make everything blurry and wibbly wobbly for someone else.

Our eyes have the opposite effect of the lens, so the lens cancel them out and we see clearly, to put it simply.

no wait that's a way better explanation