Myopia Control and Prevention

Can Nearsightedness Be Prevented?

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Myopia, also known as nearsightedness, occurs when the eyeball is longer than normal or when the cornea is steeper than average. Nearsightedness causes light to focus in front of the retina instead of directly on its surface.

Someone with nearsightedness may squint noticeably when trying to view objects in the distance. They may also sit very close to the television or bring books very close to their eyes when reading. Myopia requires visual correction, usually in the form of eyeglasses or contact lenses. Refractive surgery, such as LASIK, can also correct nearsightedness.

Myopia is receiving much more attention lately because the prevalence appears to be increasing significantly. Some countries view nearsightedness as either an epidemic or a public health crisis. In the United States, the prevalence of myopia has increased as much as 40 percent over the past 30 years. In some countries, such as China, the prevalence of myopia approaches 80 percent of the population.

Dangers of Myopia

Myopia has become a hot topic because of possible risks associate with it. High myopia, usually defined as over 5.0 units or diopters (D), creates an increased risk for glaucoma, cataracts, retinal detachment and myopic maculopathy. Just 1.0 D of myopia doubles a person's risk for myopic maculopathy and cataracts, and triples the risk of retinal detachment compared to people with emmetropia.

Emmetropia is the state when you do not need any vision correction, also known as normal vision. At 3.0 D of myopia, the risk of cataract triples and the risk of retinal detachment and myopia maculopathy is nine times that of someone with no vision problems. Furthermore, at 5.0 D of myopia, the risk of cataract is five times higher, 21 times the risk for retinal detachment and 40 times higher risk for developing myopic maculopathy.

What Causes Myopia?

No one knows for sure what causes myopia. Genetics appear to play a big role. In fact, if one parent is nearsighted, the child has a three-fold risk of becoming nearsighted. If both parents are nearsighted, that three-fold risk doubles.

Historically, there has been a long history of an association of the increase in nearsightedness in people who are actively involved in doing more near work. Even as far back as the 1800's, scientists showed a relationship that people that had higher education or worked in an occupation that included a lot of near work, were much more nearsighted than those that did not have higher education or worked outside.

However, what is still not clear is the fact that personalities that are drawn to higher intellectual occupation or ones that involve much more near work (activities that involve a short working distance) may be made up of people who are drawn to those types of jobs or scholarly studies. This area is currently being investigated by many researchers.

Most of us are exposed to an inordinate amount of near stimuli with smart phones, tablets, computers and a host of other digital devices. The jury is still out on whether this is really something we as a society need to be concerned about or not.

There are just as many studies that show that near work does not cause nearsightedness as there are studies that show that it does. It is probably a more complex algorithm that includes genetics and the amount of time spent outdoors.

Environment seems to also play a role. There is evidence that shows that time spent outdoors seems to have a protective effect. Children who spend more time outdoors are much less likely to be nearsighted. Researchers are not exactly sure why, although it is thought to have something to do with exposure to daylight or perhaps being in a larger distance-oriented environment.

Can We Prevent Myopia?

Scientists and doctors promote the idea that if the progression of myopia can be cut to approximately 50 percent, the incidence of serious complications can be cut by a significant amount. Obviously, it would be even better if we could reduce any progression at all, but most of the current ways to reduce progression of myopia have an efficacy of about 45-50 percent. Following is a list of possible ways to prevent or control myopia.

Visual correction

Many parents are concerned that if a doctor prescribes glasses to be worn most of the time, their child will become dependent on them or that the glasses themselves will cause more nearsightedness to occur. Some parents may feel that it is best to not correct the condition at all.

However, research shows that not correcting a child’s nearsightedness could actually cause the nearsightedness to worsen. In addition, under-correcting nearsightedness was once thought to have an impact on reducing the progression. However, current thought is that under-correction is associated with a higher rate of myopia progression.

Outdoor activities

Important studies have shown that time spent outdoors can delay the onset or even reduce the progression of nearsightedness. More research needs to be performed but the amount of time spent outside appears to at least be an important risk factor. Most doctors recommend that children spend at least 120 minutes outdoors every day.

The reason why this is true may be related to a reduction in obesity, an increase in vitamin D production, socialized games that occur outside or may even be related to dopamine levels in the body. One of the strongest mechanisms of action currently being studied is the amount of sun exposure or the amount of illumination or simply brightness that you receive while outside.

Low Dose Atropine

Atropine 0.1 percent ophthalmic solution has been shown to be quite effective in reducing the progression of myopia but not in slowing the rate of an increase in the length of the eyeball. However, many of the studies are showing a very high rate of success.

Some studies show as high as 90 percent reduction in progression. Atropine is given in eye drop form daily, usually at bedtime. The exact mechanism is not known. Studies have shown low dose atropine to be safe. However, some practitioners are cautious, as high dose atropine can cause some undesirable side effects.

Orthokeratology

Orthokeratology, also known as corneal refractive therapy (CRT), gentle corneal molding and corneal reshaping, is a procedure in which special corneal molds similar to rigid gas permeable lenses, are fit and slept in overnight. The lenses are called reverse-geometry lenses. They flatten the cornea centrally but steepen it peripherally, causing a shape change in the cornea that reduces peripheral hyperopic defocus and creates myopic defocus which can slow the progress of myopia.

Peripheral hyperopic defocus is a complex topic but it seems to be the stimulus for the eyeball to become elongated and to become more nearsighted. A child wearing them during the night only will generally achieve near 20/20 uncorrected vision for the entire day. This induces an effect on progression of myopia and also boosts confidence for the child so that vision correction does not have to be worn during the day.

Multifocal Soft Contact Lenses

Children wearing soft multifocal lenses had 25 percent less myopia progression and 31 percent less axial elongation than those wearing single-vision lenses over two years, according to a 2014 study in Hong Kong children. Doctors believe it works by the same mechanism as orthokeratology.

The “center-distance” multifocals focus light in front of the peripheral retina, and they focus light right on the central retina, which provides people with clear vision.

A Word From Verywell

Preliminary projections based on real population data indicate that myopia will affect over 50 percent of the world’s population by 2050. Ten percent will have high myopia, which greatly increase one’s risk for glaucoma, cataracts, retinal detachment and myopic maculopathy. Myopia is a real public health concern. Research shows that myopia control can decrease the progression of nearsightedness by 50 percent. As a result, it is worthwhile to parents to begin learning about the different options currently available.

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