Myopia in Children
Is it easy for you to read a book up close but you experience difficulties reading a billboard from a distance? Chances are that you might be myopic or struggling with nearsightedness. However, have you ever thought about asking your children these questions? If the answer is no, you might want to reconsider. This is because various researches indicate that there has been a rise in myopia amongst children lately.
To provide some much needed clarity on myopia and its impact on children, we’ve invited Tan Thok Chuan, Optometrist and Founder of TC Tan Optometrist and Tan Ho Child Clinic to share his insights.
1Twenty80: What is myopia?
Tan Thok Chuan: Myopia, also known as nearsightedness or shortsightedness, is a condition in which people can see near objects well but have difficulty seeing things far away. A very common disorder among children below 20 years old, myopia occurs because the eyeball is too long/elongated, causing light to converge in front of the retina, rather than on it, resulting in difficulty seeing things at a distance.
Myopia is a degenerative condition and patients with low myopia (defined as nearsightedness of between -0.5 to -3.00 diopters*) can progress to moderate (-3.00 to -5.00 diopters) or even high myopia (-6.00 diopters and higher) if it’s not properly controlled at an early stage. Individuals with high myopia face a greater risk of sight-threatening disorders in adulthood, including glaucoma, cataract, retinal detachment, and myopic macular degeneration/myopic maculopathy, which is an irreversible condition that can lead to severe vision impairment or permanent blindness.
In Malaysia, a national eye survey conducted in 1996¹ found that uncorrected refractive errors were the leading cause of low visions among Malaysians, and the prevalence of myopia was 42 percent among Chinese and 15 percent among Malay students. Myopia incidences in Malaysia have risen since. A more recent study in Malaysia shows that by the time a child is 7 years old, about 9.8 to 10 percent of them are myopic; and up to 34.4 to 35 percent are myopic by the time they are 15 years old².
*Diopters: Lens power is measured in diopters. The higher the number, the stronger the prescription. For example, “-5.00” means that you are very nearsighted and need a five-diopter correction.
1Twenty80: What is childhood onset of myopia?
Thok Chuan: Myopia can be diagnosed in children as young as two or three years old. I have diagnosed four and five-year-olds with low myopia of around -1.00 or -2.00 diopters. While ‘low myopia’ may not ring alarm bells, it is crucial to control the myopia as early as possible because the younger the child is when myopia sets in, the higher the risk of them developing severe sight-threatening complications later in life, when the myopia progresses to high myopia.
Even a 1.00 diopter increase in myopia has been associated with a 67 percent increase in the prevalence of myopic maculopathy. Conversely, slowing down myopia by just 1.00 diopter can reduce the individual’s likelihood of myopic maculopathy by 40 percent³.
Other lifestyle factors such as increased amount of near work* coupled with a reduced time spent outdoors, has been linked to the dramatic rise in myopia levels particularly in Asia.
1Twenty80: What are some of the causes and risk factors of myopia in children?
Thok Chuan: One of the important risk factors for myopia is genetics. If one parent is myopic, there is a 18.2 percent chance of myopia developing in a child; if both parents are myopic, the risk is increased to 32.9 percent⁴.
However, recent studies show that the rate of progression of myopia globally in recent decades is not solely due to genetic factors alone. Other lifestyle factors such as increased amount of near work* coupled with a reduced time spent outdoors, has been linked to the dramatic rise in myopia levels particularly in Asia.
*Near work is considered activities done at an arm’s length, and this includes reading/studying/writing/classwork, playing video games, using handheld devices and gadgets and more.
Studies show that the rapid rise of myopia in countries like Singapore, Hong Kong, Taiwan, China, and Japan – and to a lesser but still significant extent in other Southeast Asian nations like Malaysia – has been linked to the high focus on academic performance in young children particularly in after-school tutorials⁵. Increased amount of near work activities and after-school tutorials, coupled with less time spent outdoors have therefore contributed to the early onset and rapid progression of myopia in this region.
Conversely, the same study looks at Australia and Finland as countries with high academic performance but low prevalence of myopia. We find that in these countries there is less engagement in after-school tutorials and more emphasis on spending time outdoors.
1Twenty80: Is there a connection between screen time and myopia amongst children? Does extensive screen time contribute to an increase of myopia amongst children?
Thok Chuan: Screen time, which includes using handheld digital devices, in addition to other types of near work, are considered significant risk factors for myopia in children. Unfortunately, when our eyes spend more time focusing on near objects, this makes the eyeballs longer, thereby increasing the risk and severity of myopia.
In terms of digital device use, a meta-study of over 3000 studies investigating smart device use and myopia in young adults aged between 3 months to 33 years old found that high levels of mobile phone use is associated with around a 30 percent greater risk of myopia, and when combined with excessive computer use, that risk rose up to 80 percent⁶. In other research, a Copenhagen Child Cohort Eye Study also reported that the risk of myopia increased up to 44 percent in teens who stared at screens for more than six hours daily, compared to only 0.6 percent in those who used digital devices for less than 30 minutes a day⁷. Meanwhile, near work such as reading, studying and writing increased the risk of myopia by 2 percent for every one diopter-hour more of near work per week⁸.
So, it is not just screen time or digital devices that are to be blamed but all types of near work in general.
1Twenty80: Can myopia in children be cured? If not, how can it be controlled?
Thok Chuan: Although myopia cannot be cured, it can be managed and controlled with the appropriate lifestyle modifications and treatments. A simple practice that people can follow to alleviate prolonged strain on the eye is the ’20-20-20’ rule. That is, for every 20 minutes spent using a screen or doing near work, look away at something 20 feet away from you, for at least 20 seconds.
In addition to reducing screen time and near work, parents can encourage more time outdoors as Ultraviolet-B rays (UVB) have been shown to stimulate dopamine from the retina, which slows down the growth/elongation of the eye. In fact, the World Health Organization (WHO) points out that children who spend more than two hours a day outdoors have a lower risk of myopia than children who spend less, even if they continue to do near work or have two myopic parents⁹.
Managing myopia in children requires more than just clear vision from ordinary glasses or contact lenses. Thanks to advancements in research and technology, eyecare practitioners now have several new tools to help control the progression of myopia, including special spectacles or contact lenses, such as the overnight lenses, as well as daily disposable dual-focus contact lenses.
As myopia in children can progress rapidly, it is crucial to provide intervention at the earliest possible stage. Finally, myopia progression can be put under control with atropine eye drops, which in Malaysia, can only be prescribed by an ophthalmologist.
Having myopia in childhood, even at low levels, means that the myopia will progress to high myopia in the future, if left uncontrolled or unchecked.
1Twenty80: Can myopia lead to blindness?
Thok Chuan: Having myopia in childhood, even at low levels, means that the myopia will progress to high myopia in the future, if left uncontrolled or unchecked. Patients with high myopia have an increased risk of vision complications such as retinal detachment, vitreous detachment, glaucoma and myopic macular degeneration/ myopic maculopathy, which can result in severe vision impairment and even blindness.
Steps you can take to manage or slow down the progression of your child’s myopia:
Look into your family and identify if there is a history of nearsightedness or other eye conditions.
Ensure that your child gets an early eye exam if there is a history of any eye related conditions in your family.
Ensure that your child gets an early eye exam if there is a history of any eye related conditions in your family.
Encourage your children to spend some time outdoors and you can also spend some quality time with them away from smart devices and television screens.
Source: WebMD
References:
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7. Foreman, J., Salim, A. T., Koca, D., & Dirani, M. (2021, May 17). What Does Science Say About Screen Time and Childhood Myopia?. In Review of Myopia Management. Retrieved from https://reviewofmm.com/what-does-science-say-about-screen-time-and-childhood-myopia/
8. Huang, H. M., Chang, D. S., & Wu, P. C. (2015). The Association between Near Work Activities and Myopia in Children—A Systematic Review and Meta-Analysis. In National Library of Medicine. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4618477/#:~:text=In%20our%20study%2C%20the%20association,antagonistic%20factors%20associated%20with%20myopia.
9. Kocur I, Resnikoff S, Mariotti S, et al (2015). The impact of myopia and high myopia. Report of the Joint World Health Organization-Brien Holden Vision Institute Global Scientific Meeting on Myopia. In Epidemiology of eye and vision conditions. Retrieved from https://www.researchgate.net/publication/318216691_The_impact_of_myopia_and_high_myopia_Report_of_the_Joint_World_Health_Organization-Brien_Holden_Vision_Institute_Global_Scientific_Meeting_on_Myopia
