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Understanding Focusing Problems

Your vision depends on how light is focused in your eye. An eye has different parts, such as the cornea, lens, and iris. These parts work together to bend (refract) and focus light rays. With normal vision, light is focused on the back of the eyeball. This area is called the retina. But in some cases, the eye is not the right shape. This causes light to focus in the wrong place. It makes vision blurry. There are 3 common problems with focusing: farsightedness (hyperopia), nearsightedness (myopia), and astigmatism.

Normal vision happens when light focuses on the retina.

Cross section of eye showing light focusing on retina.
Normal.

Farsightedness happens when light focuses behind the retina. Nearby objects look blurry.

Cross section of eye showing light focusing in front of retina.
Farsighted.

Nearsightedness happens when light focuses in front of the retina. Distant objects look blurry.

Cross section of eye showing light focusing in front of retina.
Nearsighted.

Astigmatism happens when light focuses in more than one place. Both nearby and distant objects can look blurry.

Cross section of eye showing light focusing in more than one place.
Astigmatism.

Age-related focus problems

With age, the lens becomes stiff. Stiffening of the lens makes it harder for the lens to change shape, as needed, to focus light. This leads to trouble focusing on nearby objects (presbyopia).

Online Medical Reviewer: Chris Haupert MD
Online Medical Reviewer: Raymond Kent Turley BSN MSN RN
Online Medical Reviewer: Rita Sather RN
Date Last Reviewed: 8/1/2020
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