Farsightedness or Hyperopia
People who are farsighted have eyes that are too short. The rays of light are thus bundled behind the retina. The image on the retina is not in focus.
The lens of the eye can compensate farsightedness for a long time. By changing its shape, the lens of the eye increases its refractive power, causing the rays of light to be projected onto the retina. Until they reach old age, farsighted people can usually focus well on objects at a distance. People who are farsighted have difficulty reading at an earlier age, however. As the lens’ ability to change shape is already being used to see things faraway, only a smaller fraction of this ability can be devoted to reading. The ability of the lens to change shape decreases with age; people who are farsighted need reading glasses at an earlier age.
Farsightedness can be corrected with glasses, contact lenses or by an operation, e.g. laser treatment.