Rays of light that enter the eye are focused by the lens to land on the retina so that we can get a clear view of the world. But this doesn’t always work…
What is it?
When the light rays focus somewhere in front of the retina, the person is nearsighted (myopic). A child may be nearsighted because the eye is longer than average, because the cornea or lens bends light more than average, or because the lens is farther forward in the eye than average. Nearsightedness is a type of refractive error.
Contrary to common myths, nearsightedness has not been shown to be caused by or worsened by reading in a dim light, reading too close, or reading too much.
Usually, nearsighted children can see close objects clearly, but distant objects appear blurred.
The distance to the outer edge of clear vision varies with the degree of myopia.
Who gets it?
Most children are born with mild farsightedness (hyperopia). This improves as the eyeball grows and lengthens.
Nearsightedness is most common in the school-aged years but it can be present at birth or at an early age. This is most common in premature babies or in babies whose parents were nearsighted as children.
What are the symptoms?
The main symptom is blurred vision of objects in the distance. Children may not notice or articulate this as a problem. They may prefer examining objects that are close in front of them. They may see better while squinting or frowning.
Is it contagious?
How long does it last?
Because the length of the eyeball grows during childhood, nearsightedness often worsens throughout childhood. Sometimes it worsens quite rapidly. It then stabilizes when growth of the eyes slows and stops.
How is it diagnosed?
The degree of nearsightedness can be measured accurately at any age, without cooperation from the child. The eyes often need to be dilated for the examination.
In older children, nearsightedness is sometimes measured by placing different strength lenses in front of the eye, and asking which one allows them to see better.
How is it treated?
Glasses or contact lenses are usually considered necessary to treat nearsightedness. They often have to be replaced frequently as the nearsightedness worsens during the years of rapid growth. Sometimes new glasses are needed every few months.
Medicines, bifocals, and removing the glasses for near vision have not been shown to help.
How can it be prevented?
Nearsightedness is difficult to prevent, but it is possible to prevent years of undiagnosed nearsightedness. All children should have vision screening at regular intervals around well-child exams. Premature babies, and especially those with retinopathy, should have formal eye exams. Children whose parents are nearsighted should have the refractive state of their eyes measured.