Myopia (or nearsightedness) affects 20% to 30% of the population. Still, this eye disorder is easily corrected with eyeglasses, contact lenses, or surgery.
People who have myopia or nearsightedness have difficulty seeing distant objects but can see nearly clearly items. For example, a nearsighted person may not be able to make out highway signs until they are just a few feet away.
Causes of Myopia
Nearsighted people have what is called a refractive error. This means that the light rays bend incorrectly into the eye to transmit images to the brain. In people with myopia, the eyeball is too long. The cornea has too much curvature, so the light entering the eye is not focused correctly. Light rays of images focus on the retina, the light-sensitive part of the eye, rather than directly on the retina, causing blurred vision.
Myopia runs in families and usually appears in childhood. Sometimes the condition plateaus, or sometimes it worsens with age.
Symptoms of Myopia
Nearsighted people often complain of headaches, eye strain, squinting, or fatigue when driving, playing sports, or looking more than a few feet away.
Myopia can be easily diagnosed using standard eye exams given by an eye doctor.
Glasses, contact lenses, or refractive surgery can correct myopia.
With myopia, your prescription for glasses or contact lenses is a negative number, such as -3.00. The higher the number, the stronger your lenses will be.
Refractive surgery can reduce or even eliminate your dependence on glasses or contact lenses. The most common procedures for myopia are performed with a laser, including:
- Photorefractive keratectomy. Also called PRK, a laser is used to remove a corneal tissue layer, which flattens the cornea and allows light rays to focus closer to or even on the retina.
- Laser-assisted in situ keratomileuses. Commonly called LASIK, a laser is used to cut a flap through the top of the cornea; a laser removes some corneal tissue, then the flap is dropped back into place. LASIK is the most common surgery used to correct nearsightedness.
- Corneal rings. Plastic corneal rings, called Intacs, are implanted into the eye to alter the cornea’s shape. One advantage of the rings is that they may be left in place permanently, removed in case of a problem, or adjusted should a prescription change be necessary.