Are digital devices a new risk factor for myopia?
Authors: James Loughman, Daniel Ian Flitcroft
Journal: The Lancet Digital Health (2021)

In the Lancet Digital Health, Joshua Foreman and colleagues1Foreman J Salim AT Praveen A et al.Association between digital smart device use and myopia: a systematic review and meta-analysis.Lancet Digit Health. 2021; (published online Oct 5.)https://doi.org/10.1016/S2589-7500(21)00135-7Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar provide a systematic review and meta-analysis examining whether the increasing digitalisation of children's lives represents an emergent risk factor for myopia. Digital device use and associated adverse health effects is now recognised as an increasing problem among children.2Park JH Park M Smartphone use patterns and problematic smartphone use among preschool children.PLoS One. 2021; 16e0244276PubMed Google Scholar, 3Lissak G Adverse physiological and psychological effects of screen time on children and adolescents: literature review and case study.Environ Res. 2018; 164: 149-157Crossref PubMed Scopus (158) Google Scholar This analysis,1Foreman J Salim AT Praveen A et al.Association between digital smart device use and myopia: a systematic review and meta-analysis.Lancet Digit Health. 2021; (published online Oct 5.)https://doi.org/10.1016/S2589-7500(21)00135-7Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar therefore, provides a timely evidence evaluation relevant to eye care practitioners interested in finding ways to control myopia progression.4Zloto O Wygnanski-Jaffe T Farzavandi SK Gomez-de-Liaño R Sprunger DT Mezer E Current trends among pediatric ophthalmologists to decrease myopia progression–an international perspective.Graefes Arch Clin Exp Ophthalmol. 2018; 256: 2457-2466Crossref PubMed Scopus (19) Google Scholar To better understand the association between myopia and digital smart device use (ie, tablet computers and smartphones), available studies were grouped for analysis according to whether smart device use was considered independently (10 studies) or in combination with computers (10 studies) or other forms of near-vision tasks (13 studies).1Foreman J Salim AT Praveen A et al.Association between digital smart device use and myopia: a systematic review and meta-analysis.Lancet Digit Health. 2021; (published online Oct 5.)https://doi.org/10.1016/S2589-7500(21)00135-7Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar Their finding that smart device use 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, represents the most compelling evidence to date suggesting a link between digital device use and myopia. However, the authors raise legitimate concerns about the methodological limitations and reliance on cross-sectional evidence among included studies, and urge a cautious overall interpretation of the results. Despite the observed association between smart device use and myopia, the most important outcome of this study is to highlight that there is currently insufficient evidence available to establish a causal association. Analysis of near-vision work has been a central element of myopia research for centuries. A limitation noted in this study1Foreman J Salim AT Praveen A et al.Association between digital smart device use and myopia: a systematic review and meta-analysis.Lancet Digit Health. 2021; (published online Oct 5.)https://doi.org/10.1016/S2589-7500(21)00135-7Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar relevant to ongoing studies of digital devices is the lack of separation of such devices from other forms of near-vision work. Duration of use and reading distance are highlighted as potential differences from conventional reading, but digital devices differ from books in several ways that could influence the eye. For instance, the chromatic content of the light emitted by the screen, and the luminance, contrast, and other parameters, such as screen flicker;5Thomson WD Eye problems and visual display terminals-the facts and the fallacies.Ophthalmic Physiol Opt. 1998; 18: 111-119Crossref PubMed Scopus (115) Google Scholar all of which should be considered in future studies. Although this study1Foreman J Salim AT Praveen A et al.Association between digital smart device use and myopia: a systematic review and meta-analysis.Lancet Digit Health. 2021; (published online Oct 5.)https://doi.org/10.1016/S2589-7500(21)00135-7Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar evaluated the potential problem of digital device use in myopia,1Foreman J Salim AT Praveen A et al.Association between digital smart device use and myopia: a systematic review and meta-analysis.Lancet Digit Health. 2021; (published online Oct 5.)https://doi.org/10.1016/S2589-7500(21)00135-7Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar it is worth considering whether digital devices might also provide part of the solution. Questionnaires were the sole measure of smartphone usage in 32 (97%) of 33 included studies, even though digital devices continuously collect a vast amount of data on users. As suggested by the authors,1Foreman J Salim AT Praveen A et al.Association between digital smart device use and myopia: a systematic review and meta-analysis.Lancet Digit Health. 2021; (published online Oct 5.)https://doi.org/10.1016/S2589-7500(21)00135-7Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar many of the unresolved questions raised could be addressed with research designs that incorporate the objective data collected by digital devices. If specific visual behaviours are indeed found to be causally linked with myopia, appropriate warnings and limits could easily be incorporated into the devices. Such granular data could also unravel the complex association between near-vision work and myopia. Digital devices are already advancing treatment for other ocular conditions, such as amblyopia.6Xiao S Gaier ED Mazow ML et al.Improved adherence and treatment outcomes with an engaging, personalized digital therapeutic in amblyopia.Sci Rep. 2020; 10: 1-8Crossref PubMed Scopus (8) Google Scholar Elucidation of how the retinal image (eg, aberrations, defocus, and contrast) controls eye growth could also allow development of child-friendly digital myopia interventions. None of the evidence included in the study1Foreman J Salim AT Praveen A et al.Association between digital smart device use and myopia: a systematic review and meta-analysis.Lancet Digit Health. 2021; (published online Oct 5.)https://doi.org/10.1016/S2589-7500(21)00135-7Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar was derived from randomised controlled trials of smartphone use. Such a trial would be justified, if challenging (practically and ethically) to conduct, from the perspective of limiting or increasing children's digital device access. The COVID-19 pandemic has provided a natural experiment, whereby children have been exposed to increased screen time as a matter of public policy, with the switch to online learning during the pandemic. A recent study from China reported a −0·3 dioptres myopic shift and a 1·4–3·0-fold increase in myopia prevalence among children aged 6–8 years following home confinement.7Wang J Li Y Musch DC et al.Progression of myopia in school-aged children after COVID-19 home confinement.JAMA Ophthalmol. 2021; 139: 293-300Crossref PubMed Scopus (80) Google Scholar Among children being given low dose atropine eye drops to reduce myopia progression, a 43% increase in myopia progression and a 25% increase in axial elongation was observed following the COVID-19 outbreak compared with before the outbreak. The increases were significant among younger children (aged 5–10 years) but not in older children (aged 11–15 years).8Yum HR Park SH Shin SY Influence of coronavirus disease 2019 on myopic progression in children treated with low-concentration atropine.PLoS One. 2021; 16e0257480Crossref PubMed Scopus (1) Google Scholar Notably, device usage among these children increased two-fold whereas outdoors exposure was more than halved in the same period. COVID-19 lockdowns have altered children's behaviour, restricted outdoors exposure, and increased leisure and learning time spent using digital devices.8Yum HR Park SH Shin SY Influence of coronavirus disease 2019 on myopic progression in children treated with low-concentration atropine.PLoS One. 2021; 16e0257480Crossref PubMed Scopus (1) Google Scholar, 9Moore S Faulkner G Rhodes R et al.Impact of the COVID-19 virus outbreak on movement and play behaviours of Canadian children and youth: a national survey.Int J Behav Nutr Phys Act. 2020; 17: 85Crossref PubMed Scopus (343) Google Scholar This new evidence,1Foreman J Salim AT Praveen A et al.Association between digital smart device use and myopia: a systematic review and meta-analysis.Lancet Digit Health. 2021; (published online Oct 5.)https://doi.org/10.1016/S2589-7500(21)00135-7Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar coupled with the changes observed during COVID-19 lockdowns,6Xiao S Gaier ED Mazow ML et al.Improved adherence and treatment outcomes with an engaging, personalized digital therapeutic in amblyopia.Sci Rep. 2020; 10: 1-8Crossref PubMed Scopus (8) Google Scholar, 7Wang J Li Y Musch DC et al.Progression of myopia in school-aged children after COVID-19 home confinement.JAMA Ophthalmol. 2021; 139: 293-300Crossref PubMed Scopus (80) Google Scholar suggests that the behavioural alterations associated with digital devices could indeed increase myopia in children. Although better quality evidence is required to establish causality, the possibility that excessive smart device use could lead to an increase in myopia, and hence ocular health complications, needs to be considered by practitioners involved in the care of children at risk. As the authors1Foreman J Salim AT Praveen A et al.Association between digital smart device use and myopia: a systematic review and meta-analysis.Lancet Digit Health. 2021; (published online Oct 5.)https://doi.org/10.1016/S2589-7500(21)00135-7Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar note, the recent global rise in myopia prevalence pre-dates the advent of digital devices. However, this observation does not preclude the possibility that such devices might affect future trends in myopia. The recent rise in premature mortality and morbidity associated with non-communicable disease illustrates how population health is being shaped by powerful social, political, and economic forces that encourage unhealthy lifestyles and increase access to health-harming products, thereby promoting the development of chronic disease.10Allen L Are we facing a noncommunicable disease pandemic?.J Epidemiol Glob Health. 2017; 7: 5-9Crossref PubMed Scopus (33) Google Scholar There is little downside then, it would seem, to limiting digital device use among children. How parents can control access to digital technology and find the right balance between helpful and harmful use for their children is another matter entirely! JL has received research grant funding support from Health Research Board (Ireland), Nevakar and Coopervision; has consultancy relationships with Dopavision, Kubota Vision, Ocuco, and Ebiga Vision; has received honoraria from Thea Pharmaceuticals and Ocuco for lectures; has received equipment on loan from Topcon and Coopervision; has two patents pending (one in myopia management data analytics and one in biomonitoring for low dose atropine treament in myopia); and is Director of Ocumetra, all in the field of myopia management. DIF has received research grant funding support from Health Research Board (Ireland), Nevakar, and Coopervision; has consultancy relationships with Dopavision, Kubota Vision, Essilor, and Johnson & Johnson; has received equipment on loan from Topcon and Coopervision; has two patents pending (one in myopia management data analytics and one in biomonitoring for low dose atropine treament in myopia); and is Director of Ocumetra, all in the field of myopia management. DIF has also previously collaborated with one of the Article authors (RRAB) on published work. Association between digital smart device use and myopia: a systematic review and meta-analysisSmart 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. Full-Text PDF Open Access