What is the Difference Between Nearsightedness and Farsightedness?

Fundamentally, a nearsighted person is able to see objects that are close to them clearly, while faraway objects are blurry. Farsightedness is the opposite condition, in which far objects appear clearer than those that are closer to the subject.

The difference in what causes these conditions resides in the shape of the eye and how light is focused within it.

For an object to be viewed clearly, light must be focused properly upon the retina in the back of the eye. This focus can shift as we look at images at different distances.

In the eye of a nearsighted person, light is focused in front of the retina instead of directly upon it. This leads to far objects appearing blurry.

In the eye of a farsighted person, light is focused behind the retina. This leads to close objects appearing blurry.

Corrective lenses solve this focusing problem by altering the way light is focused within the eye, making vision clearer both near and far.