Nearsightedness

Alternative names: Myopia, Shortsightedness

Myopia is the ability to see well at close distances, but not at longer distances.  It is the opposite of farsightedness (hyperopia).

Incidence; Causes and Development; Contributing Risk Factors

The prevalence of myopia has grown drastically in the last few decades, from around 25% of the U.S. population in the 1970s to over 40% in 2000.  The precise reason is not known, but may include eye fatigue from prolonged near-vision tasks such as reading and increased computer use.

Loss of ability to focus can start to decline in childhood and continue until the 20s, when usually it stabilizes.  It is caused by the eyes losing their ability to focus on distant objects.

Nearsightedness is partly due to genetics.  Premature babies are more likely to develop eye conditions in later life that affect the shape of the eye, and therefore may be more likely to develop nearsightedness.

Signs and Symptoms

Symptoms include the need to squint to see clearly, frequent blinking and eye rubbing.

Prognosis

Myopia almost never worsens rapidly, and usually stabilizes by the time a person reaches their 20s.