A common question I’m asked by parents and teachers alike relates to the impact of screen time on children’s and adolescents’ vision. There’s been increasing media attention on the impact of digitalised childhoods and adolescence and the possible association between increasing rates of myopia, near-sightedness. Basically, they want to know if too much time on tech is damaging their child’s eyesight.
This is an important topic and one that parents and educators should be concerned about, given that the World Health Organization (sic) estimates that half of the population of the world may be myopic by 2050.
At this stage, there’s an insufficient corpus of empirical evidence and longitudinal data to provide a definitive answer as to whether screen time is responsible for increasing rates of myopia in childhood and adults. However, there are some studies that certainly suggest that there’s an association between with myopic shifts, especially in children, and their digital behaviours.
A study published in January 2021 in the JAMA Ophthalmol Journal found that the prevalence of myopia, which is near-sightedness, in Chinese children rose significantly during the COVID lockdown. Home confinement appeared to be “associated with a substantial myopic shift (approximately −0.3 diopters) for children aged six to eight years.” There was an almost 400% increase in six year olds. The study involved 123 000 school children aged 6 to 8 years of age who were confined to home isolation during the COVID pandemic in 2020.
In six-year-olds, the prevalence of short-sightedness was approximately three times higher in 2020 than in 2015 to 2019, representing an almost 400% increase. For seven-year-olds it was two times higher in 2020 or a 200% increase, and for those children who were aged eight, it was 1.4 times higher, representing a 40% increase. At this point, it’s important to note that this study showed a correlation and did not prove causation.
Colloquially referred to as ‘quarantine myopia’ there are concerns that increased amounts of time on digital devices is associated with myopia. This study showed that there’s an association with a significant myopic shift for children aged 6 to 8 years according to 2020 school-based.
So why the increase in childhood myopia?
// Displacement of outdoor activities– Concerns have been raised about the ‘displacement effect’ of screens on the developing eye. Insufficient time spent outdoors has been recognised as a major risk factor for myopia developmentHome confinement has resulted in children spending significantly less time outdoors, due to their increased time on digital devices. There is still some uncertainty as to why outdoor time has been shown to delay or prevent the onset of myopia. There are studies underway to determine if Vitamin D plays a critical role in this process, or if outdoor time tends to result in the eye focusing on objects at a distance (and therefore decreasing near visual tasks) and therefore being a protective factor.
Simple strategies to help minimise myopic progression
I asked Optometrist Karen Garner-Hamilton for her suggested tips:
// Take regular breaks– the 20-20-20-20 rule is a simple idea. Every 20 minutes your child/teen (or you) uses any type of screen, take a minimum of 20 seconds, to blink 20 times (our eyes need a lot of lubrication when we stare at a screen) and look at a fixed object about 20 feet away (approximately 6 metres).
// Green time– outdoor exposure, at least 90 minutes per day, especially for children, is the best known protective factor at this stage to prevent myopia. Plus, there’s a myriad of other benefits associated with outdoor time (movement, connection, play, problem solving).
// Limit your near work activities- this one is the hardest strategy to implement, given that our kids and teens are spending more and more time online. However, where you can, limiting leisure screen time (so excluding school work) to under 2 hours is recommended. The human eye was designed to look in the distance. Biologically, we are designed for hunting and gathering food, which was a distance task, not for looking at a screen (or reading).
// The Elbow Rule- The final recommendation is the working distance that near work is performed and the elbow rule is an easy way to demonstrate this to children. Placing your hand on your forehead your book or device should be no closer than your elbow.
These along with regular eye examinations with your optometrist are the best way to help minimise the impact your child’s screen time is having on their eyes.
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