Because everyone is different and unique, some people do not see as well as others. Our eyes work by bending and focusing an image, but sometimes a person’s eyes might have more trouble with bending and focusing images in the right way. When this happens, it is usually caused by the length or shape of their eye, which can cause trouble seeing things far away, close up, or sometimes both.
To help people see better, eyeglasses pull and bend shapes back into place! Have you ever looked up close at a pair of eyeglasses? You might notice that the lenses themselves are slightly curved, or that when you look through them objects appear rounded and bent. -- For the person that wears those glasses, the lenses are pulling and bending in ways that their eyes cannot!
Eye doctors help people who don’t see well to know which kinds of glasses they need to fix their problem. For example, a nearsighted person (who has trouble seeing things far away) generally needs glasses that bend slightly inwards, while a farsighted person (who has trouble seeing things close up) generally needs glasses that bend slightly outwards! The special shapes of these lenses bend an image back into shape for the person who wears them!