Monday, June 16, 2003 at 9:25 AM ET | Written by: L. E. Leguire Ph.D., MBA | Ohio Lions Eye Research Foundation
What is myopia?
Myopia is often called “nearsightedness.” People with myopia can see close objects clearly while objects farther away appear blurred.
All images that the eye can see have light rays that come from the image and enter the eye to allow us to see. In normal vision, light rays (depicted by the black lines in the diagrams) from an object are bent by the cornea and lens at the front of the eye so they focus on the retina, where the image of the object is transmitted to the brain for 20/20 vision.
In myopia, the eye is too long so that the light rays focus in front of the retina (see diagram 2). This causes a blurred image. Glasses are needed to help rays focus properly on the retina so that a clear image can be seen.
What causes myopia?
Myopia is most often caused by excessive lengthening of the eye during childhood. In other words, the eye grows too long.
Recent studies have shown that a parental history of myopia is the strongest risk factors for the development and progression of myopia. Close-up work, such as reading, computer work and close television viewing may influence the development of myopia.
Can myopia be prevented from progressing?
There are currently no approved drugs or devices to prevent myopia from progressing. Children with myopia wear glasses or contact lenses to enable them to see distant objects clearly. Surgical correction of myopia (RK, PRK and LASIK) is not available for children because of the on-going growth of the child’s eye. However, none of these methods have been proven to prevent myopia from progressing.
Besides the inconvenience, why try to prevent the progression of myopia?
Research has shown that people with myopia are far more likely to develop sight-threatening medical complications later in life. For example, myopic people are three times more likely to develop glaucoma (high eye pressure) which can lead to vision loss or blindness.
Importantly, people with myopia more often develop retinal detachment, requiring surgery to reattach the retina. And, retinal detachment can lead to severe visual loss or even blindness. Retinal detachment in people with mild myopia occurs 8 times more often than in people with normal vision. In people with severe myopia, retinal detachment occurs 330 times more often.
Illustration – Myopia and hyperopia