Farsightedness, or hyperopia, is a focusing problem caused by an eyeball that is shorter than normal. Because of the reduced length, the lenses do not have enough space in which to consistently bring light rays to a focal point by the time they reach the retina. Hence the focal point of an close object falls behind the retina resulting in a blurred image.

The effects of farsightedness vary with age because of the diminishing flexibility of the eye's inner lens. Young people may not notice the effects of mild farsightedness because the flexibility of their inner lens allows them to adapt. But as the eyes begin to age near objects become increasingly difficult to see. Later in life, nearly all focal ranges may be unclear.