In news that would likely make my son jump for joy, it seems digital device use is not associated with myopia development, according to a recent meta-analysis of 15 studies comprising 50,000 subjects.1 Kids everywhere—well, the ones who read up on medical news—might rejoice at the prospect of an end to parental scolding to ‘put down your phone already.’ But what should optometrists make of it? This swims against the tide of conjecture linking prolonged screen time with myopia and muddies the waters for ODs looking to advise patients and parents.
Increased near-work trends have been in place at least since 1980, the report notes, long before the ubiquity of digital devices. Worldwide, this chiefly reflects the development of Asian populations that have been transitioning from rural to urban societies. “Education and intensive schooling may have a larger contribution to the increase in myopia prevalence than screen time,” the paper explains. Screen use in some ways is merely a substitution for other near work, such as reading or pen-and-paper educational activities.
While screens may not be public enemy #1, the study found, they aren’t wholly blameless either. The authors did note a contributory effect. Time outdoors remains the best protective measure against the impetus toward myopia. Because they dissuade kids from outdoor play, digital screens do have some complicity, plus other ill effects.
Here the authors cite a World Health Organization (WHO) report that advises limiting screen time for children under age five, as it “may increase sedentary behavior with negative impact for children’s health.” For kids between ages one and four, screen time should be no more than one hour per day, the WHO says. Sedentary habits, of course, are a breeding ground for childhood obesity and diabetes, and should be discouraged on those grounds alone, to say nothing of any myopia effect.
How might all this change what you advise? There’s no guidance in the report but it seems intuitive to still encourage mitigation of screen time, especially among young kids. Dismayingly, the report notes “the age children start to use smartphone devices is getting younger (22% start at three years old or less) and one in three children one- to six-years old use smartphones between one and two hours per day.” If nothing else, such habits expose kids to blue light and decrease blink rates more so than any prior generation.
Like millions of other parents, my wife and I want to encourage our son to develop good habits and avoid bad ones. (Always eager to help the boy, we ate half his Halloween candy last year.) But reports like this that confound the experts leave us somewhat adrift. It’s naïve to think kids are going to eschew such a useful (and, yes, fun) thing as a phone or tablet. Still, it pains me to see stats about very young kids being glued to a screen, especially when time outdoors confers so many benefits. To my three-year-old son, I still say, for now: Sorry, kiddo, go fly a kite.
1. Lanca C, Saw S. The association between digital screen time and myopia: a systemic review. Ophthal Physl Opt. January 13, 2020. [Epub ahead of print].