According to the American Optometric Association (AOA), nearsightedness (myopia) is a vision impairment in which faraway objects are out of focus but objects near the eyes are clearly viewed. Nearsightedness is caused by either an excessively long eyeball or when the cornea (the clear the dome-shaped frontal portion of the outer covering of the eye) is overly curved. The AOA says approximately 30 percent of the U.S. population is nearsighted. There are a number of corrective lenses to treat myopia.
Single Vision Lenses
The Mayo Clinic says corrective eye glasses rectify nearsightedness by canceling out the enhanced curvature of your cornea or the extended length of your eye. Types of corrective lenses include both eyeglasses and contact lenses.
The AOA says eyeglasses are the preferred vision correction option for nearsightedness. What's called a single-vision lens establishes or restores normal vision regardless of whether objects are blurry at far away distances or fuzzy when close up.
Bifocals
A bifocal or progressive addition lens may be prescribed when myopia is the result of an activity that demands concentrated near-vision work or when a nearsighted patient is over age 40.
Multifocal lenses offer varying strengths within the lens that can allow for focused vision off in the distance while also providing visual clarity of nearby objects.
Some nearsighted individuals may get more focused vision from contact lenses than traditional eyeglasses can provide. The extensive array of contact lenses include hard and soft lenses, extended wear (designed for up to one week of nonstop use), disposable (a new pair is worn every day, typically the most costly), rigid gas permeable (offer greater durability, less irritation) and bifocal lenses.
Ortholkeratology
The AOA says corneal refractive therapy (ortholkeratology), consists of adjusting a number of firm contact lenses to restructure the cornea. These retainer contact lenses are typically left in for several hours at a time (overnight) and then taken out.
In moderate cases of myopia, orthokeratology may provide normal vision that can last for the duration of the day following night wear of the contacts. The precise wearing schedule will be set by your eye doctor.
