IMPROVE YOUR EYESIGHT
Do you have problems seeing clearly up close or at a distance? Chances are you have what doctors call a ‘refractive error’ that can be corrected with eyeglasses or contact lenses.
The most common type of refractive error is called myopia, or nearsightedness. If you have myopia, objects that are nearby are seen clearly, but distant objects do not come into proper focus. Nearsightedness occurs if your eyeball is too long or the cornea has too much curvature so that the rays of light entering your eye are not focused correctly on the back of the eye, or retina.
Nearsightedness is a very common vision condition that affects nearly 30 percent of the U.S. population. It normally first occurs in school-age children and adolescents. The eye continues to grow during childhood, so nearsightedness generally develops by age 20.
Other common refractive conditions are hyperopia (farsightedness), astigmatism (occurring when the cornea is not perfectly spherical), and presbyopia (usually in older adults and correctable with bifocals). Emmetropia is the term used when light is properly focused in the eye.
Signs and Symptoms
The characteristic sign of nearsightedness is difficulty seeing distant objects like a movie or TV screen or chalkboard. These objects appear more or less fuzzy, depending on distance.
An adult or an older child will probably recognize the problem and realize that he or she should be examined by an optometrist or ophthalmologist. Signs to be aware of in a younger child are sitting very close to a television, holding pictures or books very close to the eyes, or frequent headaches. In any case, even if there is no apparent problem, a child’s vision should be screened periodically by the pediatrician.
As you age, the natural lens in your eye loses its ability to focus on near objects. This is a condition that is universal and is called presbyopia.
Although the shape of the eyeball is probably largely determined by genetics, there may also be an environmental component to myopia.
There is growing evidence that nearsightedness may be influenced by increased near work and less outdoor play during childhood. Research is being done regarding eye drops, which can slow down the progression of myopia. In the meantime, myopia is a benign condition and easily corrected.
A comprehensive examination by an eye care professional will include testing for nearsightedness and other refractive errors. Your optometrist or ophthalmologist can then prescribe eyeglasses or contact lenses to optically correct the condition by altering the way that light enters your eyes.
You may only need to wear eyeglasses for certain activities, like watching a movie or driving a car, or they may need to be worn most of the time. Follow instructions as to how long contact lenses should be left in the eye, or else inflammation or infection can occur. You should never sleep in your contact lenses, as there is significant risk of serious, potentially blinding infection.
Refractive surgery or laser procedures are also possible treatments for nearsightedness. LASIK and PRK are the most common procedures. If presbyopia is present, the traditional treatments include reading glasses and bifocals or no-line (progressive) glasses. An alternative to decrease reliance on glasses is to wear contact lenses, with one eye focused for distance and the other eye focused for near. This is called monovision. Monovision can also be set up permanently with LASIK or PRK. Your eye care professional can discuss these treatments with you to see if you are a candidate, and can also discuss newer technology which may be available. This is an area of much research, and there is currently no cure for presbyopia without glasses.
Refractive treatments improve the ability to focus light onto the retina, but they do not change the process that leads to elongation of the eye and the effects this can have on the retina in myopia.