Cause
Farsightedness (hyperopia) occurs when light entering
the eye through the lens is focused
behind the retina
instead of directly on it (refractive error). This is caused by an eye that is too short, whose cornea is not
curved enough, or whose lens sits farther back in the eye than normal.
Farsightedness is usually inherited: a person with one or more parents who are
farsighted is likely to be farsighted as well.
See information about
eye anatomy and function.
Many people are born farsighted. Some outgrow it as their eyes grow
and develop. Children who do not outgrow farsightedness are often able to
accommodate for the condition—their eyes work harder
to focus and make up for the refractive error.
With age, the eyes lose their ability to accommodate for refractive
errors, and farsightedness becomes more apparent. Everyone slowly loses the
ability to focus his or her lens, usually around age 40. People who are
nearsighted (myopic), farsighted (hyperopic), or perfectly focused for distance
(emmetropic) will all eventually lose the ability to focus on near objects.
This is called
presbyopia.
In rare instances, diseases such as
retinopathy, eye tumors, and lens dislocation can also
contribute to the development of farsightedness.