October 15, 2021
By Dwight Akerman, OD, MBA, FAAO, FBCLA
A major international study published in one of the world’s leading medical journals has revealed a link between screen time and higher risk and severity of myopia in children.
The open-access research, published in The Lancet Digital Health, was undertaken by researchers and eye health experts from Singapore, Australia, China, and the U.K. The authors examined more than 3,000 studies investigating smart device exposure and myopia in children and young adults aged between 3 months and 33 years.
The authors used the gold-standard approach — a comprehensive systematic review and meta-analysis — to collect all the published research on the link between smart device screen exposure and myopia. After analyzing and statistically combining the available studies, they revealed the most compelling evidence to date implicating digital devices, particularly screen time, as a risk factor for myopia in children.
The study’s authors reviewed over 3,000 published scientific papers using strict inclusion criteria and found 33 articles from 14 countries across Asia and Europe that investigated a link between digital devices and myopia to include in the analysis. They discovered that the majority of these studies reported that exposure to digital screens (including longer periods of screen time and earlier age of first screen exposure in children) was significantly associated with a higher risk of myopia, an increase in the severity of myopia, and greater axial elongation, which is the primary anatomical change that results in the onset of myopia. When combined through statistical modeling, the findings from all the available studies showed that, overall, high levels of smart device screen time were associated with almost a 30% higher risk of myopia. When excessive computer screen time was added, this increased to nearly 80%.
This critical research emphasizes the need for eye care professionals to continually educate children about proper environmental and visual hygiene behavior.
Association Between Digital Smart Device Use and Myopia: A Systematic Review and Meta-analysis
Joshua Foreman, Arief Tjitra Salim, Anitha Praveen, Dwight Fonseka, Daniel Shu Wei Ting, Ming Guang He, Rupert R A Bourne, Jonathan Crookston, Tien Y Wong, Mohamed Dirani
Purpose: Excessive use of digital smart devices, including smartphones and tablet computers, could be a risk factor for myopia. We aimed to review the literature on the association between digital smart device use and myopia.
Methods: In this systematic review and meta-analysis, we searched MEDLINE and Embase and manually searched reference lists for primary research articles investigating smart device (i.e., smartphones and tablets) exposure and myopia in children and young adults (aged 3 months to 33 years) from database inception to June 2 (MEDLINE) and June 3 (Embase), 2020. We included studies that investigated myopia-related outcomes of prevalent or incident myopia, myopia progression rate, axial length, or spherical equivalent. Studies were excluded if they were reviews or case reports, did not investigate myopia-related outcomes or did not investigate risk factors for myopia. Bias was assessed with the Joanna Briggs Institute Critical Appraisal Checklists for analytical cross-sectional and cohort studies. We categorized studies as follows: category one studies investigated smart device use independently; category two studies investigated smart device use in combination with computer use; and category three studies investigated smart device use with other near-vision tasks that were not screen-based. We extracted unadjusted and adjusted odds ratios (ORs), β coefficients, prevalence ratios, Spearman’s correlation coefficients, and p values for associations between screen time and incident or prevalent myopia. We did a meta-analysis of the association between screen time and prevalent or incident myopia for category one articles alone and for category one and two articles combined. Random-effects models were used when study heterogeneity was high (I2>50%), and fixed-effects models were used when heterogeneity was low (I2≤50%).
Results: 3325 articles were identified, of which 33 were included in the systematic review and 11 were included in the meta-analysis. Four (40%) of ten category one articles, eight (80%) of ten category two articles, and all 13 category three articles used objective measures to identify myopia (refraction), whereas the remaining studies used questionnaires to identify myopia. Screen exposure was measured using questionnaires in all studies, with one also measuring device-recorded network data consumption. Associations between screen exposure and prevalent or incident myopia, an increased myopic spherical equivalent, and longer axial length were reported in five (50%) category one and six (60%) category two articles. Smart device screen time alone (OR 1·26 [95% CI 1·00–1·60]; I2=77%) or in combination with computer use (1·77 [1·28–2·45]; I2=87%) was significantly associated with myopia. The most common sources of risk of bias were that all 33 studies did not include reliable measures of screen time, seven (21%) did not objectively measure myopia, and nine (27%) did not identify or adjust for confounders in the analysis. The high heterogeneity between studies included in the meta-analysis resulted from variability in sample size (range 155–19 934 participants), the mean age of participants (3–16 years), the standard error of the estimated odds of prevalent or incident myopia (0·02–2·21), and the use of continuous (six [55%] of 11) versus categorical (five [46%]) screen time variables
Conclusion: Smart device exposure might be associated with an increased risk of myopia. Research with objective measures of screen time and myopia-related outcomes that investigates smart device exposure as an independent risk factor is required.
Foreman, J., Salim, A. T., Praveen, A., Fonseka, D., Ting, D. S. W., He, M. G., … & Dirani, M. (2021). Association between digital smart device use and myopia: a systematic review and meta-analysis. The Lancet Digital Health.