Nearsightedness is a visual condition where a person is able to see things up close, but not far away.
Nearsightedness occurs when light rays entering the front of the eye focus in front of the retina instead of on it. The retina is the membrane in the back of the eye that receives images and carries their signal through the optic nerve to the brain. In most nearsighted people, the light rays fail to reach the retina because the eye is too long from front to back.
Sometimes the length of the eye is normal but the cornea, the part of the eye that lets in light, is too steep, causing light rays to come together too quickly. Myopia usually develops in children between the ages of 11 and 13, but can be seen in children much younger.
Sometimes the condition does not start until adulthood. Nearsightedness that begins after a person reaches middle age may indicate the start of cataracts. Cataracts are a condition in which the lens, a clear membrane behind the pupil, becomes cloudy.
Symptoms of this condition can include: blurred distance visionsquintingrubbing the eyes
Myopia is caused by: an imbalance between the way the cornea and lens bend light raysan abnormal length of the eyeball
Myopia is probably genetic, although doing a lot of close-up work may contribute to the condition. The theory is that large amounts of close work fattens the lens, causing nearsightedness.
There is no way to prevent nearsightedness or stop its progression.
An eye care professional may suspect myopia in a person complaining of blurred vision when reading a blackboard or road signs from a distance. He or she can diagnose this condition during the portion of a routine eye examination.
People who are very nearsighted are more likely to develop serious eye problems such as: holes or tears in the retina.high pressure in the eye, called glaucomadegeneration in the central portion of the retina, called myopic macular degenerationcataracts
As they age, these people must be followed more closely by an eye care professional to prevent vision loss.
Treatment for myopia includes: glassescontact lensesrefractive laser surgery
A person who is slightly nearsighted needs to update his or her glasses prescription every 2 to 3 years, or sooner if he or she thinks it is needed. A person who is very nearsighted needs to see an eye care professional more often to be checked for high pressure in the eye, degeneration in the retina and cataracts.