What Is Myopia?
Nearsightedness, or myopia, as it is medically termed, is a vision condition in which near objects are seen clearly, but distant objects do not come into proper focus.
Approximately one in four Americans is nearsighted, totaling 70 million people. The degree of myopia can vary from low (-1 to -3 diopters) to high (greater than 6 diopters). Myopia is not caused by reading at an early age, prolonged reading, reading in the dark, watching TV too closely, wearing glasses too strong, wearing glasses too weak, or other similar folklore. Some controversy exists over whether myopia can be made worse be prolonged near work as a child, but this has never been proven.
In studies, it has been correlated with higher I.Q.s., but this probably has to do with the fact that myopes tend to read more since that’s where they can see the best without glasses (see below). Myopia tends to run in families, so it is probably inherited. Myopia tends to start in the early teens (earlier for high myopes), and increases as the eye grows in length during puberty. It tends to stabilize after age 18.
What causes nearsightedness?
When your eyeball is too long or the cornea has too much curvature, light entering the eye is not focused properly. Some evidence supports the theory that nearsightedness is hereditary. There is some evidence that nearsightedness may also be caused by the stress of too much close vision work.
In a nearsighted eye, the cornea is too steeply curved for the length of the eye, causing light rays to focus in front of the retina. Distant objects appear blurred or fuzzy because the light rays are not in focus by the time they reach the retina. The greater the myopia, the more the light rays converge and the more blurred distant objects appear.
Near objects, viewed at the proper distance, can be seen clearly because the focus of their light rays matches the refractive error of the nearsighted eye. For example, a patient with -2 diopter correction is naturally in focus at 0.5 meters (18 inches). Having the focus point of the eye within arm’s length is an intrinsic advantage to the myope, who always has the option of seeing well at close range without optical correction. Indeed, many myopes instinctively remove their spectacles for near work, particularly after the onset of presbyopia.
Will I have to wear glasses?
You may need glasses to enable you to see more clearly. If your condition warrants, Dr. Milano will prescribe corrective lenses for you. You may only need them for certain activities, like watching television, going to a movie, or driving a car.
Will glasses/contact lenses cure nearsightedness?
Eyeglasses or contact lenses optically correct the problem by altering the way the light images enter your eyes, but they do not cure nearsightedness. Contact lens correction reduces the optical problems that plague eyeglass wearers, but they have their own unique problems including high-maintance care solutions, corneal warping, corneal suffocation, corneal infections, and eyelid allergies. Some people lose their ability to wear contact lenses – particularly individuals with dry or sensitive eyes.
How is nearsightedness diagnosed?
Nearsighted children are usually easy to identify because they often squint or have trouble seeing the chalkboard, the movie screen, the television set or other distant objects. When your optometrist gives you a comprehensive eye examination, it will include a test for nearsightedness.
How will nearsightedness affect my lifestyle?
If glasses or contact lenses are prescribed, it may take you a few days to adjust to them and to seeing clearly. After that, nearsightedness will probably not significantly affect your lifestyle. However, more severely nearsighted individuals may find the condition limits their choice of occupation.