The Study
An Objective Comparison of Light Intensity and Near-Visual Tasks Between Rural and Urban School Children in China by a Wearable Device Clouclip
This study looked at how much sunlight and screen time urban and rural kids get, and found that urban kids get less sun and do more close-up work. But it didn't check if those kids had worse eyesight — so we can't say the sun or screen time caused their eyes to get worse, only that the habits were different.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
This study looked at how much light and how close kids in cities and villages in China look at things during their day.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 544 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — less sunlight and more very-close screen time in cities may help explain why more city kids become nearsighted.
- 2City kids saw less sunlight (614 lux at school vs 918 in villages) and spent more time reading or using screens very close (30.9 cm vs 34.8 cm), especially after school.
- 3Village kids spent more time on screens on weekends, likely because grandparents watched them less.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Translational Vision Science & Technology
Year
2019
Authors
Longbo Wen, Qian Cheng, Weizhong Lan, Yingpin Cao, Xiaoning Li, Yiqiu Lu, Zhenghua Lin, Lun Pan, Haogang Zhu, Zhikuan Yang
Related Content
Claims (6)
Extended close-up visual work without looking at distant objects leads to worsening nearsightedness due to continuous tension in the eye's focusing muscle and changes in eye shape.
Schoolchildren in urban areas of China spend more of their after-school time doing close-up tasks like reading or screen use, and hold materials closer to their eyes than children in rural areas.
Urban schoolchildren in China receive more daylight during weekdays than on weekends, while rural schoolchildren experience similar daylight levels regardless of the day of the week.
Schoolchildren in urban areas of China are exposed to lower levels of ambient light during school hours and on weekends than schoolchildren in rural areas, with measured differences of 614 lux versus 918 lux during school and 445 lux versus 882 lux on weekends.
Urban schoolchildren in China spend more of their after-school time doing close-up work within 30 centimeters of their eyes than rural schoolchildren, with 49% of their near-work time at this distance versus 40% in rural areas.
Rural schoolchildren in China spend a larger share of their weekend near-work time on screens than urban schoolchildren, even though they spend less total time on near-work activities, suggesting their screen use is less structured and occurs with less parental oversight.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.