Myopia risk increases gradually for every additional hour of screen time: JAMA

A new study published in the Journal of American Medical Association showed that an additional hour of digital screen time each day is linked to a 21% increased risk of myopia.

New types of near-work activities have emerged as a result of the last 10 years' increasing usage of digital gadgets. Digital screen time is commonly used in research to describe how long people spend using electronic displays, such as computers, gaming consoles, smartphones, tablets, and TVs. This can be done for specific devices or as a total amount of time spent using them.

There is a pressing need to learn more about the connection between digital screen time and myopia as kids use smart devices at earlier ages and spend more time on them. The dose-response relationship and safe exposure threshold are yet unknown, despite the fact that digital screen time has been linked to myopia. Thus, this study was to assess the dose-response relationship between the risk of myopia and the amount of time spent on digital devices.

From the beginning until November 25, 2024, full-length publications from peer-reviewed journals were found using the databases of EMBASE, PubMed, CINAHL, the Cochrane Library, and ClinicalTrials.gov, with no limitations on research design, publication date, or language. This study found primary research publications examining the relationship between myopia-related outcomes (such as prevalent or incident myopia and the rate of myopia development) and exposure to digital screen devices (such as cellphones, gaming consoles, tablets, laptops, or televisions).

In compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-Analysis of Observational Studies in Epidemiology (MOOSE) reporting criteria, two independent reviewers used a structured approach to retrieve data. The pattern of the relationship between screen time and myopia was investigated using a random-effects, dose-response meta-analysis (DRMA).

The outcomes of this study found that an extra hour of screen time per day was linked to increased risks of myopia in the linear DRMA of 45 trials with 335,524 individuals. Higher risks of myopia were also found with increased screen time, ranging from 1 hour of daily exposure to 4 hours, according to the nonlinear DRMA of 34 trials with 314 910 individuals.

Myopia risk increased dramatically between 1 and 4 hours of daily screen exposure, and then more gradually after 4 hours, according to the dose-response curve. Overall, digital screen time was linked to higher probabilities of myopia, according to this systematic review and DRMA. These results may provide valuable information for further study and guide public health and educational initiatives to combat the myopia epidemic.

Source:

Ha, A., Lee, Y. J., Lee, M., Shim, S. R., & Kim, Y. K. (2025). Digital screen time and myopia: A systematic review and dose-response meta-analysis. JAMA Network Open, 8(2), e2460026. https://doi.org/10.1001/jamanetworkopen.2024.60026