In a recent study published in BMC Public Healthresearchers systematically reviewed and quantified the epidemiological evidence on the association between screen time exposure and myopia in children and adolescents.
Study: The association between screen time exposure and myopia in children and adolescents: a meta-analysis. Image credit: Inna Kot/Shutterstock.com
Record
Myopia or myopia is a refractive error characterized by the excessive elongation of the eyeball, leading to an increased risk of pathological changes in the eyes, such as cataracts, glaucoma, retinal detachment and macular degeneration, which can cause irreversible vision loss.
Environmental factors such as education, work and outdoor activities significantly influence the prevalence of myopia. Screen time, including the use of computers, televisions, video games and mobile devices, is now pervasive in the lives of children and adolescents, with increased exposure from an early age.
Recent epidemiological studies show conflicting results regarding the association between screen time and myopia.
Further research is needed to clarify the conflicting findings regarding the relationship between screen time exposure and myopia in children and adolescents and to inform effective prevention and control strategies.
About the study
In this systematic review and meta-analysis, researchers conducted literature review, data extraction, risk of bias assessment and analysis.
According to the Preferred Reports for Systematic Reviews and Meta-Analysis (PRISMA) 2020 statement, eligibility criteria included studies in children and adolescents that examined screen time exposure (categorical or continuous) and reported adjusted odds ratios (ORs) and 95% confidence intervals (CIs). ) for myopia.
Observational studies using cross-sectional, cohort or case-control designs were included, selecting the most recent and comprehensive publication when multiple studies on the same population were reported.
PubMed, Embase, and Web of Science literature searches through June 1, 2023, used terms related to screen and myopia. Exclusions included reviews, letters, commentaries, occupational exposure studies, non-human studies, ecological studies and studies without impact assessments.
Data extraction included author details, year of publication, country, study design, sample size, type of display device, definition of myopia, outcomes (OR and 95% CI), and adjustments for confounders. Quality assessment used the Newcastle Ottawa Scale (NOS), rating studies of high, moderate or low quality.
Statistical analysis used R software, using fixed or random effect models based on heterogeneity. Subgroup and sensitivity analyzes were performed, and publication bias was assessed using funnel plots, Egger’s test, and the trim and fill method.
Study results
In the study, 6,493 articles were identified from PubMed, Embase and Web of Science. After excluding 1,159 duplicate studies, 5,295 unrelated studies were removed during title and abstract screening.
Thirty-nine articles were assessed for eligibility, but 20 were excluded due to univariate analysis, lack of available data, or lack of myopia prevalence.
Ultimately, 19 studies involving 102,360 participants were included, with 91,282 in cross-sectional studies (N=15) and 11,078 in cohort studies (N=4).
Thirteen studies (68%) used cycloplegic refraction, three (16%) used self-reported myopia, and three (16%) performed optometry without cycloplegia. The studies came from nine countries: two from North America, seven from Europe, six from East Asia, two from South Asia and two from Southeast Asia.
According to the NOS checklist, 14 studies (74%) were considered high quality (score ≥ seven stars), while the remaining five studies (26%) were of moderate quality (score 5 or 6 stars).
Potential sources of bias included small sample sizes in six studies, inadequate strategies to address confounding factors in five studies, lack of adjustment for key confounders in five studies, and failure to use cycloplegic refraction to confirm cases of myopia in five studies.
Eleven studies involving 90,415 participants examined the relationship between categorical exposure to screen time (high vs. low) and myopia in children and adolescents. Higher category of screen time exposure was significantly associated with myopia in cross-sectional studies (OR=2.24, 95%CI: 1.47–3.42) and cohort studies (OR=2.39, 95%CI: 2 .07–2.79).
Subgroup analysis by display device type showed significant associations with myopia for computers and televisions but not for smartphones. Subgroup analysis by study quality, geographic region, and survey period revealed significant associations in high-quality studies, in East and South Asia, and in surveys conducted after 2008.
Eight studies involving 11,925 participants analyzed continuous exposure (in increments of 1 hour/day) to screen time and myopia. There was no association in cross-sectional studies (OR=1.15, 95%CI: 0.97–1.37), but a significant association was found in cohort studies (OR=1.07, 95%CI: 1.01–1, 13).
Significant associations for computer screen time were observed in cross-sectional studies and in East Asia. Due to the limited number of studies, further subgroup analyzes were not performed for cohort studies.
Publication bias was detected in cross-sectional studies for both the high versus low screen time groups and per 1-hour increase in screen time, as indicated by the Egger test. After trim and fill analysis, pooled ORs remained significant.
Sensitivity analysis showed strong effects for the high vs. low screen time group, but not for the 1 hour/day increment screen time group.
conclusions
In summary, this comprehensive meta-analysis found significant associations between computer and television screen time and myopia, but not smartphones. Regional differences were noted, with significant correlations in East and South Asia.
The study highlighted the need for targeted prevention strategies, including reducing activities near work and promoting time outdoors.
