Smart device use was linked to higher odds of child myopia

The short answer

A 2021 pooled analysis found that smart device use, such as smartphones and tablets, was associated with higher odds of myopia (short-sightedness) in children, though the underlying studies were inconsistent and largely relied on self-reported screen time. Eye-health bodies separately point to outdoor time as linked to lower myopia risk, without being certain why.

What the evidence says

Foreman, Salim, Praveen and colleagues published their systematic review in Lancet Digital Health, online 5 October 2021, after screening 3,325 articles down to 33 for review and 11 for meta-analysis. Smart device screen time alone was associated with higher odds of myopia (odds ratio 1.26, 95% confidence interval 1.00 to 1.60), with the confidence interval's lower bound sitting right at the no-effect line. The authors were explicit about the limitations behind that number: studies used questionnaires rather than objective tracking to measure screen exposure, used inconsistent definitions of myopia, and often did not adjust for other known risk factors.

For context

An odds ratio with a confidence interval touching 1.00 is a real but fragile signal, not a settled cause. The US National Eye Institute, in guidance last updated 4 December 2024, separately states that children who spend more time outdoors are less likely to be nearsighted, while adding that experts are not sure why; family history is described as the clearer risk factor. Reading the two together, the pattern that best fits current evidence is less screens damage eyes and more however children spend their indoor, near-focus time, more outdoor time is associated with lower risk, which is a different and more actionable distinction.

A practical next step

Given the outdoor-time association is better established than the screen-time odds ratio, you might treat outdoor time as the more promising lever, alongside routine eye checks rather than screen-time restriction alone.

• How much time does your child spend outdoors on a typical school day, separate from screen habits?
• Is your child's near-focus time mostly screens, or also reading and homework, which raises similar questions?
• Has your child had a recent vision check that could catch early changes regardless of the cause?

The evidence supports treating smart device use as one plausible contributor to childhood myopia risk worth monitoring, not as a proven cause on its own, and supports outdoor time as a separately useful habit whatever the mechanism turns out to be.