The incidence of nearsightedness in the U.S. is growing quickly. According to the National Eye Institute, while nearsightedness (myopia) grew from appearing in one quarter of the American population among people aged 12 to 54 in the early ‘70’s, in the early 2000’s it was found in over 40% of the same population, and the incidence has been accelerating since. Nearsightedness is the most common refractive error in the U.S.
The reason for the increase in myopia is believed by eye care professionals to be caused not only by genetics, but also by eye fatigue caused by extended use of computers and other digital devices. Some studies have also suggested myopia is tied to lack of developmental cues furnished by natural sunlight or time spent focusing on objects in the distance.
Myopia Symptoms And Signs
If you or your children have difficulty seeing distant objects clearly but see well for closer tasks such as working on the computer and reading, you/they may be suffering from myopia.
Nearsightedness causes symptoms such as headaches caused by eye fatigue and the need to squint to see words farther away. If myopia is uncorrected, you or your children may also suffer from feeling fatigued when driving or playing sports.
If these signs or symptoms are experienced while wearing glasses or contact lenses, a comprehensive eye examination with an optometrist should be scheduled to see if a stronger prescription is needed.
Causes of Myopia
Myopia occurs when light rays focus at a point in front of the retina rather than directly on its surface. This means the eyeball is too long relative to the focusing power of the cornea and lens of the eye. The condition can also be caused by the cornea and/or lens being too curved for the length of the eyeball. In some cases, nearsightedness is due to a combination of factors.
Myopia typically begins in childhood. Children may have a higher risk if their parents are nearsighted. In many cases, nearsightedness stabilizes in early adulthood, but it sometimes progresses with age.
Glasses, contact lenses or refractive surgery can correct nearsightedness. Depending on the degree of myopia, a person will need to wear their glasses or contact lenses either all the time or only when they need very clear distance vision, like when driving, reading a whiteboard or watching a movie.
Good choices for eyeglass lenses for nearsightedness include high-index lenses (for thinner, lighter glasses) and anti-reflective coating. Also, photochromic lenses protect the eyes from UV and high-energy blue light, reducing the need for prescription sunglasses outdoors.
For people who are nearsighted, the first number ("sphere") on their eyeglass or contact lens prescription will start with a minus (–) sign. The higher the number, the harder time they have focusing in the distance.