Myopia control: Is there a cure for short-sightedness?
If your child has myopia (shortsightedness), you're probably wondering if there is a cure — or at least something that can be done to slow its progression so your child doesn't need stronger glasses year after year.
For years, optometrists, ophthalmologists and researchers have been wondering the same thing. And there's good news: A number of recent studies suggest it may indeed be possible to at least control myopia by slowing its progression during childhood and among teenagers.
What is myopia control?
Although an outright cure for shortsightedness has not been discovered, your optometrist can now offer a number of treatments that may be able to slow the progression of myopia.
These treatments can induce changes in the structure and focusing of the eye to reduce stress and fatigue associated with the development and progression of shortsightedness.
Why should you be interested in myopia control? Because slowing the progression of myopia may keep your child from developing high levels of shortsightedness that require thick, glasses and have been associated with serious eye problems later in life, such as early cataracts or even a detached retina.
Currently, three types of treatment are showing promise for controlling myopia:
Multifocal contact lenses
Here's a summary of each of these treatments and of recent myopia control research:
Orthokeratology is the use of specially designed gas permeable contact lenses that are worn during sleep at night to temporarily correct shortsightedness and other vision problems so glasses and contact lenses aren't needed during waking hours.
Some optometrists also use "ortho-k" lenses to control myopia progression in children. Evidence suggests shortsighted kids who undergo several years of orthokeratology may end up with less myopia as adults, compared with children who wear glasses or regular contact lenses during the peak years for myopia progression.
Some optometrists refer to these lenses as "corneal reshaping lenses" or "corneal refractive therapy (CRT)" lenses rather than ortho-k lenses, though the lens designs may be similar.
In 2011, researchers from Japan presented a study that evaluated the effect of ortho-k lenses on eyeball elongation in children, which is a factor associated with myopia progression.
A total of 92 shortsighted children completed the two-year study: 42 wore overnight ortho-k lenses and 50 wore conventional glasses during the day. The average age of children participating in the research was about 12 years at the beginning of the study, and children in both groups had essentially the same amount of pre-existing myopia (-2.57 D) and the same axial (front-to-back) eyeball length (24.7 mm).
At the end of the study, children in the glasses group had a significantly greater increase in the mean axial length of their eyes than children who wore the ortho-k contact lenses. The study authors concluded that overnight orthokeratology suppressed elongation of the eyes of children in this study, suggesting ortho-k might slow the progression of myopia, compared with wearing regular glasses.
In 2012, the same researchers published the results of a similar five-year study of 43 shortsighted children that showed wearing ortho-k contact lenses overnight suppressed axial elongation of the eye, compared with wearing conventional glasses for myopia correction.
Also in 2012, researchers in Spain published study data that revealed children 6 to 12 years of age with -0.75 to -4.00 D of myopia who wore ortho-k contact lenses for two years had less myopia progression and reduced axial elongation of their eyes than similar children who wore eyeglasses for myopia correction.
In October 2012, researchers in Hong Kong published yet another study of the effect of ortho-k contact lenses on controlling myopia progression in children. A total of 78 shortsighted children ages 6 to 10 years at the onset of the investigation completed the two-year study.
Children who wore ortho-k lenses had a slower increase in axial length of their eyes by 43 percent, compared with kids who wore glasses. Also, the younger children fitted with the corneal reshaping GP lenses had a greater reduction of myopia progression than the older children.
Furthermore, as myopia control expert Jeffrey J. Walline, OD, PhD, from the Ohio State University College of Optometry pointed out in his analysis of the study published in the same issue of Investigative Ophthalmology & Visual Science, the benefit of slowed myopia progression from wearing the ortho-k lenses extended beyond the first year of myopia treatment.
In March 2014, researchers in Taiwan published results of a study that compared the use of ortho-k contact lenses vs. atropine eye drops for the control of myopia in children ages 7 to 17. Participants had myopia ranging from -1.50 to -7.50 D (with up to -2.75 D of astigmatism) at the beginning of the three-year study period.
The two myopia control treatments produced comparable results: children wearing the ortho-k lenses experienced myopia progression of -0.28 D per year, and those who wore glasses and applied 0.125 percent atropine eye drops nightly had an average myopia progression of -0.34 D per year.
Although this study did not include a control group that received no treatment to control myopia, the study authors mentioned that in similar studies the progression of shortsightedness among children wearing ortho-k lenses for myopia control was roughly half that of those who received no myopia control treatment over a two-year period.
Multifocal contact lenses
Multifocal contacts are special lenses that have different powers in different zones of the lens to correct presbyopia as well as shortsightedness or longsightedness (with or without astigmatism).
Researchers and optometrists are finding that conventional or modified multifocal soft contact lenses are also effective tools for myopia control.
In 2010, researchers from Australia, China and the United States presented data from a study of experimental myopia control contact lenses worn by Chinese schoolchildren for six months. The contacts had a special dual-focus multifocal design with full corrective power in the centre of the lens and less power in the periphery.
Participants were between the ages of 7 and 14 at the onset and had -0.75 to -3.50 dioptres (D) of myopia, with no more than 0.50 D of astigmatism. A total of 65 children wore the experimental multifocal contacts, and 50 children wore glasses. After six months, the children wearing the multifocal contact lenses had 54 percent less progression of their myopia than the children wearing glasses.
In June 2011, researchers in New Zealand reported on a comparison of an experimental multifocal soft contact lens and conventional soft lenses for myopia control in children. A total of 40 nearsighted children ages 11 to 14 participated in the study. The children wore the multifocal contact lens on one randomly assigned eye and a conventional soft contact lens on the fellow eye for 10 months, then switched the lenses to the opposite eye for another 10 months.
In 70 percent of the children, myopia progression was reduced by 30 percent or more in the eye wearing the experimental multifocal contact lens in both 10-month periods of the study.
In November 2013, researchers in the U.S. published the results of a two-year study that revealed short sighted children who wore multifocal soft contact lenses on a daily basis had 50 percent less progression of their myopia, compared with similarly short sighted children who wore regular soft contact lenses for two years.
Children participating in the study ranged in age from 8 to 11 years and had -1.00 to -6.00 D of myopia at the time of enrolment.
The study authors concluded that the results of this and previous myopia control studies indicate a need for a long-term, randomised clinical trial to further investigate the potential of multifocal soft contact lenses to control the progression of shortsightedness in children and thereby reduce risks associated with high myopia.
Children's Vision News
Nearly half of the global population may be shortsighted by 2050, researchers say
Researchers at the Brien Holden Vision Institute in Sydney, reviewed data from 145 studies and analysed the prevalence of myopia and high myopia among 2.1 million study participants. The group also data published since 1995 to estimate trends from 2000 to 2050.
What they found was alarming.
An estimated 1.4 billion people worldwide were shortsighted in 2000. That's about 23 percent of the total global population. But by 2050, the researchers predict this figure will soar to 4.8 billion, afflicting 49.8 percent of the world's population.
The good news is, there are ways to protect your children from landing on the wrong side of this statistic. One key may be to encourage them to turn off their electronic devices and head outdoors.
The study points out that the projected increases in myopia are driven principally by lifestyle changes characterised by more near-work activities, like using computers and portable electronic devices, including smartphones. Other proposed risk factors for myopia include long hours spent in the classroom and less time outdoors, especially among young children in countries such as Singapore, Korea, Taiwan and China.
Although the vision of most people with shortsightedness can be corrected with glasses and contact lenses, high levels of myopia increase the risk of eye diseases such as cataracts, glaucoma, retinal detachment and myopic macular degeneration — all of which can cause irreversible vision loss.
Multifocal glasses have also been tested for myopia control in children, but results have been less impressive than those produced with multifocal contacts.
A number of studies published between 2000 and 2011 found that wearing multifocal glasses does not provide a significant reduction in progressive myopia for most children.
The Correction of Myopia Evaluation Trial (COMET), a study published in 2003, found that progressive glasses lenses, compared with regular single vision lenses, did slow myopia progression in children by a small but statistically significant amount during the first year. But the effect wasn't significant in the next two years of the study.
But in March 2014, researchers in Australia and China published the results of a three-year clinical trial that evaluated the progression of shortsightedness among 128 myopic children ages 8 to 13 years. All participants had experienced at least -0.50 D of myopia progression the year preceding the start of the study.
One group of children wore conventional single vision glasses, a second group wore bifocals, and a third group wore bifocal lenses with prism. After three years, children who wore either type of bifocal eyeglasses had significantly less mean progression of shortsightedness (-1.01 D to -1.25 D) than children who wore single vision lenses (-2.06 D).
Detecting myopia early
The best way to take advantage of methods to control myopia is to detect shortsightedness early.
Even if your child is not complaining of vision problems (shortsighted kids often are excellent students and have no visual complaints when reading or doing other schoolwork), it's important to schedule routine eye exams for your children, starting before they enter pre-school.
Early childhood eye tests are especially important if you or your spouse are shortsighted or your child's older siblings have myopia or other vision problems.
What about myopia control in adults?
Myopia typically develops during the early school years and tends to progress more rapidly in pre-teens than in older teenagers. This is why myopia control studies usually involve relatively young children.
While it's true that myopia can also develop and progress in young adults, though this is less common. And it's possible that an adult's eyes may not respond to myopia control treatments the same way a child's eyes do. For these reasons, it's likely that most research on controlling myopia progression will continue to focus on shortsighted children rather than adults.
Can eye exercises cure myopia?
Some of these eye exercise programmes recommend you ask your optometrist to write you a glasses prescription that intentionally under-corrects your shortsightedness for full-time wear as an adjunct treatment to performing the exercises. The claim is that the exercises and under-correction of your myopia will reduce your shortsightedness, so you will need less vision correction as time goes on.
It's worth noting here that research has shown under-correction of myopia is ineffective at slowing myopia progression and may in fact increase the risk of shortsightedness getting worse. Also, intentional under-correction of myopia causes blurred distance vision, which may put your child at a disadvantage in the classroom or in sports and affect their safety.
My opinion (and the opinion shared by most optometrists and vision researchers) is that these eye exercises do not cure myopia, are highly suspect, and are not supported by well-designed independent research. Buyer beware!
Page published on Monday, 16 March 2020
Page updated on Tuesday, 27 July 2021