Hyperopia is a common refractive error, also known as farsightedness. Farsighted people see things best when they are very far away but have trouble seeing things that are closer. Hyperopia occurs when light entering the eye comes into focus behind the retina instead of precisely on the retina. This can be caused by a cornea that is too flat, by an eye that is too short, or by a combination of both problems. People with mild hyperopia can still see things that are far away, but people with severe hyperopia can have trouble seeing clearly, even at a distance. In addition, hyperopia often becomes worse as the eyes lose focusing power with age.