Myopia (nearsightedness): Causes, Treatment

Myopia (also called nearsightedness) is the most common cause of impaired vision in people under age 40. In recent years, its prevalence is growing at an alarming rate.

Globally, research suggests that in the year 2000, roughly 25 percent of the world's population was nearsighted but by the year 2050, it's expected that roughly half the people on the planet will be myopic.

Myopia Symptoms

If you are nearsighted, you will have difficulty reading road signs and seeing distant objects clearly, but will be able to see well for close-up tasks such as reading and computer use.

Other signs and symptoms of myopia include squinting, eye strain and headaches. Feeling fatigued when driving or playing sports also can be a symptom of uncorrected nearsightedness.

If you experience these signs or symptoms while wearing your glasses or contact lenses, schedule an eye exam with your optometrist or ophthalmologist to see if you need a stronger prescription.

What causes myopia?

Myopia occurs when the eyeball is too long, relative to the focusing power of the cornea and lens of the eye. This causes light rays to focus at a point in front of the retina, rather than directly on its surface.

Nearsightedness can also be caused by the cornea and/or lens being too curved for the length of the eyeball. In some cases, myopia occurs due to a combination of these factors.

Myopia typically begins in childhood, and you may have a higher risk if your parents are nearsighted. In most cases, nearsightedness stabilizes in early adulthood but sometimes it continues to progress with age.

Myopia treatment

Nearsightedness can be corrected with refractive surgery.

Refractive surgery can reduce or even eliminate your need for glasses or contacts. The most common procedures are performed with an excimer laser.

• In PRK the laser removes a layer of corneal tissue, which flattens the cornea and allows light rays to focus more accurately on the retina.

• In LASIK and FEMTO LASIK — the most common refractive procedures — a thin flap is created on the surface of the cornea, a laser removes some corneal tissue, and then the flap is returned to its original position.

This post originally appeared on Health Line.