What does myopia mean? What causes the eye problem? Nearsightedness, or myopia, is the most common refractive error of the eye, and it has ended up being more prevalent over the last few years.
In fact, a recent research study by the National Eye Institute (NEI) reveals the frequency of myopia grew from 25 percent of the U.S. population (ages 12 to 54) in 1971-1972 to a massive 41.6 percent in 1999-2004.
Though the exact cause for this increase in nearsightedness among Americans is unknown, many optometrist feel it has something to do with eye fatigue from computer use and other extended near vision jobs, coupled with a genetic predisposition for myopia.
Myopia Symptoms and Signs
If you are nearsighted, you typically will have trouble reading road signs and seeing distant items plainly, but will have the ability 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 tired out when owning 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 extensive eye examination with your eye doctor or eye doctor to see if you require a more powerful 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, instead of straight on its surface.
Nearsightedness also can be caused by the cornea and/or lens being too curved for the length of the eyeball. Sometimes, myopia is due to a combination of these factors.
Myopia usually starts in childhood and you may have a higher risk if your parents are nearsighted. Most of the times, nearsightedness supports in early their adult years but sometimes it continues to advance with age.
A 2012 review could not find strong proof for any cause, although many theories have actually been challenged. Since twins and loved ones are more likely to obtain myopia under similar situations, there should be a hereditary aspect, however since myopia has actually been increasing so rapidly throughout the developed world, environmental aspects must be more important.
Myopia Treatment
Nearsightedness can be corrected with glasses, contact lenses or refractive surgery. Depending upon the degree of your myopia, you might need to wear your glasses or contact lenses all the time or only when you require very clear range vision, like when owning, seeing a chalkboard or enjoying a film.
If you’re nearsighted, the first number (“sphere”) on your spectacles prescription or contact lens prescription will be preceded by a minus sign (–). The greater the number, the more nearsighted you are.
Refractive surgery can minimize and even remove your requirement for glasses or contacts. The most typical treatments are performed with an excimer laser.
- In PRK the laser removes a layer of corneal tissue, which flattens the cornea and enables light rays to focus more precisely on the retina.
- In LASIK – the most common refractive procedure — a thin flap is produced on the surface of the cornea, a laser eliminates some corneal tissue, then the flap is gone back to its initial position.
Then there’s orthokeratology, a non-surgical procedure where you use special stiff gas permeable (RGP or GP) contact lenses during the night that reshape your cornea while you sleep. When you get rid of the lenses in the early morning, your cornea temporarily keeps the new shape, so you can see plainly throughout the day without glasses or contact lenses.
Recent epidemiologic work supports a greater role for outdoor activity in relieving myopia progression rather than the previous touted young- age near-work activity model.
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Orthokeratology and an associated GP contact lens procedure called corneal refractive therapy (CRT) have actually been shown effective at momentarily correcting moderate to moderate amounts of myopia. Both treatments are good options to surgery for individuals who are too young for LASIK or are not good candidates for refractive surgery for other reasons.
Implantable lenses called phakic IOLs are another surgical option for remedying nearsightedness, particularly for people with high amounts of myopia or thinner-than-normal corneas that could increase their risk of complications from LASIK or other laser vision correction procedures.
Phakic IOLs work like contact lenses, other than they are surgically positioned within the eye and generally are irreversible, which implies no maintenance is required. Unlike IOLs used in cataract surgery, phakic IOLs do not replace the eye’s natural lens, which is left intact.
Managing Myopia
With a growing number of individuals getting nearsighted these days, there is a lot of interest in discovering methods to manage the development of myopia in childhood.
A number of different strategies have been attempted — consisting of fitting children with bifocals, progressive lenses and gas permeable contact lenses — with mixed outcomes.
Recently, scientists in New Zealand have actually reported motivating outcomes from specifically created “dual focus” soft contact lenses for myopia control in nearsighted children. The experimental lenses have considerably less power in the periphery of the lens compared with the center, and it is thought that this “peripheral defocus” might minimize the tendency for higher lengthening of the eye that causes progressive myopia.
In a research study published in 2011, the researchers found that in 70 percent of nearsighted children (ages 11 to 14) who wore the speculative lenses in one eye and a standard soft contact lens in the other, myopia progression was decreased by 30 percent or more in the eye using the dual focus contact lens.
The apparent inhibitory effect of BSCLs on myopic progression reported in this twin study argues for further study of their efficacy as a control treatment for myopes with near esophoria.
onlinelibrary.wiley.com
Though dual focus contact lenses for myopia control are not yet readily available in the United States, research is ongoing to assess the efficiency of the lenses on a bigger population of children.
Degenerative Myopia
In most cases, nearsightedness is merely a small trouble and postures little or no risk to the health of the eye. However sometimes myopia can be so progressive and severe it is thought about a degenerative condition.
Degenerative myopia (also called malignant or pathological myopia) is a fairly unusual condition that is thought to be hereditary and usually starts in early youth. About 2 percent of Americans are affected, and degenerative myopia is a leading cause of legal blindness.
In malignant myopia, the elongation of the eyeball can happen quickly, causing a fast and severe progression of myopia and loss of vision. Individuals with the condition have actually a considerably increased risk of retinal detachment and other degenerative changes in the back of the eye, consisting of bleeding in the eye from unusual blood vessel growth (neovascularization).
Degenerative myopia also may increase the risk of cataracts.
Surgical treatment for complications of degenerative myopia consists of a combination drug and laser procedure called photodynamic therapy that likewise is used for the treatment of macular degeneration.
Likewise, a recent pilot research study found that an oral medicine called 7-methylxanthine (7-mx) was effective in slowing the elongation of the eye in nearsighted children ages 8 to 13. Studies of this type might eventually cause a reliable medical treatment for degenerative myopia.