Relative Contribution of Risk Factors for Early-Onset Myopia in Young Asian Children

Outdoor time is considered to reduce the risk of developing myopia. The purpose is to evaluate the evidence for association between time outdoors and (1) risk of onset of myopia (incident/prevalent myopia); (2) risk of a myopic shift in refractive error and c) risk of progression in myopes only. A systematic review followed by a meta‐analysis and a dose–response analysis of relevant evidence from literature was conducted. PubMed, EMBASE and the Cochrane Library were searched for relevant papers. Of the 51 articles with relevant data, 25 were included in the meta‐analysis and dose–response analysis. Twenty‐three of the 25 articles involved children. Risk ratio (RR) for binary variables and weighted mean difference (WMD) for continuous variables were conducted. Mantel–Haenszel random‐effects model was used to pool the data for meta‐analysis. Statistical heterogeneity was assessed using the I 2 test with I 2 ≥ 50% considered to indicate high heterogeneity. Additionally, subgroup analyses (based on participant's age, prevalence of myopia and study type) and sensitivity analyses were conducted. A significant protective effect of outdoor time was found for incident myopia (clinical trials: risk ratio (RR) = 0.536, 95% confidence interval (CI) = 0.338 to 0.850; longitudinal cohort studies: RR = 0.574, 95% CI = 0.395 to 0.834) and prevalent myopia (cross‐sectional studies: OR = 0.964, 95% CI = 0.945 to 0.982). With dose–response analysis, an inverse nonlinear relationship was found with increased time outdoors reducing the risk of incident myopia. Also, pooled results from clinical trials indicated that when outdoor time was used as an intervention, there was a reduced myopic shift of −0.30 D (in both myopes and nonmyopes) compared with the control group (WMD = −0.30, 95% CI = −0.18 to −0.41) after 3 years of follow‐up. However, when only myopes were considered, dose–response analysis did not find a relationship between time outdoors and myopic progression (R 2 = 0.00064). Increased time outdoors is effective in preventing the onset of myopia as well as in slowing the myopic shift in refractive error. But paradoxically, outdoor time was not effective in slowing progression in eyes that were already myopic. Further studies evaluating effect of outdoor in various doses and objective measurements of time outdoors may help improve our understanding of the role played by outdoors in onset and management of myopia.

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“…), children aged 3 years (Chua et al. ), adults aged 18–24 years (Lee et al. ) and adults aged 50 years or older (Pan et al.…”

Section: Resultsmentioning

confidence: 99%

Time spent in outdoor activities in relation to myopia prevention and control: a meta‐analysis and systematic review

Xiong

Sankaridurg

Naduvilath

et al. 2017

Acta Ophthalmologica

398

372

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“…In 7681 children aged 5–16 years old, myopia (adjusted OR = 1.17, 95% CI 1.03–1.32; p = 0.015) and high myopia prevalence (adjusted OR = 2.31, 95% CI 1.17–4.57; p = 0.016) were associated with computer use . However, in 572 children aged 3 years old the number of hours per day playing with handheld devices (adjusted OR = 1.04, 95% CI 0.67–1.61; p = 0.86) and using computers (adjusted OR = 0.92, 95% CI 0.31–2.74; p = 0.88) was not associated with myopia . At 3 years old only 6.1% of the children had myopia and exposure to digital devices might not be enough to cause myopia at this point in time.…”

Section: Resultsmentioning

confidence: 99%

The association between digital screen time and myopia: A systematic review

Lança

Saw

2020

Ophthalmic Physiologic Optic

166

146

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Purpose Digital screen time has been cited as a potential modifiable environmental risk factor that can increase myopia risk. However, associations between screen time and myopia have not been consistently reported. Although myopia prevalence increased before the massive use of digital devices in some countries, with the rise being influenced by education, there may be an added recent effect of screen time. The aim of this systematic review is to determine the association between screen time and the risk of developing (1) prevalent or incident myopia, or (2) the risk of myopia progression in children. Published manuscripts were identified in PubMed, ScienceDirect and the Cochrane Library, and citation lists were reviewed. Recent findings Fifteen studies were included (nine cross‐sectional and six cohort studies) with a total of 49 789 children aged between 3 and 19 years old. Seven studies found an association between screen time and myopia. The results showed mixed evidence with the more recent studies exposing a trend of association between hours spent by children using screens and myopia. Meta‐analysis using a random‐effects model was performed in five studies (n = 20 889) that reported odds ratio (OR). The I2 statistics was used to assess heterogeneity. A pooled OR of 1.02 (95% CI: 0.96–1.08; p = 0.48) suggests that screen time is not associated with prevalent and incident myopia in this group of five studies. Summary The results for screen time and myopia are mixed. Further studies with objective screen time measurements are necessary to assess evidence of an association between screen time and myopia.

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“…'s study in Taiwan revealed that time spent using computers was associated with a longer AL ( p = 0.001) . In contrast, handheld devices and computers were not significantly associated with SER, AL or myopia in the Singapore Cohort Study of the Risk Factors for Myopia (SCORM) study …”

Section: Discussionmentioning

confidence: 98%

Electronic devices and myopic refraction among children aged 6‐14 years in urban areas of Tianjin, China

Liu

Wei

et al. 2019

Ophthalmic Physiologic Optic

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Purpose To assess associations between different types of electronic devices, myopic refraction and ocular biometric parameters in children aged 6–14 years in urban areas of Tianjin, China. Methods A school‐based, cross‐sectional study was performed on 566 children (302 boys and 264 girls). The children underwent a comprehensive eye examination, including cycloplegic autorefraction and ocular biometry. The children's parents completed a detailed questionnaire that included each child's demographics, the use of electronic devices and other related risk factors. Results Myopia was not associated with time spent using various electronic devices. However, the mean spherical equivalent refraction (SER) decreased by 0.28 D (p = 0.042) and 0.33 D (p = 0.018) for each 1‐h increase in the time spent using smart phones and computers, respectively. In the multiple linear regression analyses of factors associated with the SER, the standardised coefficient B for time spent reading and writing was approximately four to five times larger than the standardised coefficient for time spent using smart phones or computers. Time spent using tablets and watching television was not significantly associated with the SER. A longer axial length (AL) was associated with more time spent using smart phones (B = 0.23, p = 0.006) and computers (B = 0.26, p = 0.002) but not using tablets (p = 0.45) and watching television (p = 0.45). No significant association was found between other ocular biometric parameters and time spent using various electronic devices. Conclusions On average, a more myopic SER and longer AL were both associated with more time spent using smart phones and computers, but not with time spent using tablets and watching television. The magnitude of the association between SER and time spent reading and writing was a substantially larger than that for smart phone or computer use. Different types of electronic devices had differing levels of association with myopic refraction.

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Relative Contribution of Risk Factors for Early-Onset Myopia in Young Asian Children

Abstract: Genetic factors may have a greater contribution to early development of refractive error compared to environmental factors.

Cited by 64 publications

References 36 publications

Time spent in outdoor activities in relation to myopia prevention and control: a meta‐analysis and systematic review

Time spent in outdoor activities in relation to myopia prevention and control: a meta‐analysis and systematic review

The association between digital screen time and myopia: A systematic review

Electronic devices and myopic refraction among children aged 6‐14 years in urban areas of Tianjin, China

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