{
  "abstract": "Aims To investigate the effect of time outdoors on myopic shift among premyopic children.Methods Post-hoc analysis was nested in a cluster-randomised trial of the Shanghai Time Outside to Reduce Myopia (STORM) study. 6- to 9-year-old participants without myopia from the STORM study, who wore wristwatches to monitor time outdoors from 2017 to 2018, were included. Participants were all examined with cycloplegic refraction. Daily time outdoors was objectively monitored with the wearable smartwatch. Premyopia was defined as a cycloplegic spherical equivalent (SE) from −0.50 to +0.75 (inclusive) dioptres (D). Myopic shift was SE change from baseline to 1 year follow-up.Results Among 3194 participants (1369 premyopic; mean age 8.2±0.6 years; 49.5% boys), there were no statistical differences between premyopic and hyperopic children in time outdoors (p=0.303). Hyperopes showed reduced myopic shift with increasing outdoor time (plateau at about 120 min/day). However, premyopes exhibited a J-shaped relationship between time outdoors and myopic shift. In comparison to the subgroup with daily time outdoors <60 min, the difference in SE change in the other subgroups was not statistically significant (61–90 min/d: −0.03 (95% CI −0.10 to 0.05); 91–120 min/d: −0.03 (95% CI −0.11 to 0.05)). The reduced myopic shift was only observed with time outdoors >120 min/d, although it was still not statistically significant (>120 min/d: 0.04 (95% CI −0.05 to 0.14)).Conclusions Among premyopic children, increased time outdoors has a limited protective effect on myopic shift, suggesting longer duration of time outdoors or additional interventions to prevent or delay myopia onset in this population.",
  "authors": [
    {
      "affiliations": [
        "Shanghai Eye Diseases Prevention &Treatment Center/ Shanghai Eye Hospital, School of Medicine, Tongji University, Shanghai, China",
        "National Clinical Research Center for Eye Diseases, Shanghai, China",
        "Shanghai Engineering Research Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China",
        "Eye Public Health Research Center, School of Medicine, Tongji University, Shanghai, China"
      ],
      "name": "Jun Chen"
    },
    {
      "affiliations": [
        "Shanghai Eye Diseases Prevention &Treatment Center/ Shanghai Eye Hospital, School of Medicine, Tongji University, Shanghai, China",
        "National Clinical Research Center for Eye Diseases, Shanghai, China"
      ],
      "name": "Ziyi Qi"
    },
    {
      "affiliations": [
        "Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia"
      ],
      "name": "Ian Morgan"
    },
    {
      "affiliations": [
        "Discipline of Orthoptics, Graduate School of Health, University of Technology Sydney, Sydney, New South Wales, Australia"
      ],
      "name": "Kathryn Rose"
    },
    {
      "affiliations": [
        "Centre for Eye Research Australia Ltd, East Melbourne, Victoria, Australia"
      ],
      "name": "Zhuoting Zhu"
    },
    {
      "affiliations": [
        "State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China, Guangzhou, China"
      ],
      "name": "Xiaohu Ding"
    },
    {
      "affiliations": [
        "Shanghai Eye Diseases Prevention &Treatment Center/ Shanghai Eye Hospital, School of Medicine, Tongji University, Shanghai, China",
        "National Clinical Research Center for Eye Diseases, Shanghai, China",
        "Shanghai Engineering Research Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China",
        "Eye Public Health Research Center, School of Medicine, Tongji University, Shanghai, China"
      ],
      "name": "Jingjing Wang"
    },
    {
      "affiliations": [
        "Shanghai Eye Diseases Prevention &Treatment Center/ Shanghai Eye Hospital, School of Medicine, Tongji University, Shanghai, China",
        "National Clinical Research Center for Eye Diseases, Shanghai, China",
        "Shanghai Engineering Research Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China",
        "Eye Public Health Research Center, School of Medicine, Tongji University, Shanghai, China"
      ],
      "name": "Bo Zhang"
    },
    {
      "affiliations": [
        "Shanghai Eye Diseases Prevention &Treatment Center/ Shanghai Eye Hospital, School of Medicine, Tongji University, Shanghai, China",
        "National Clinical Research Center for Eye Diseases, Shanghai, China",
        "Shanghai Engineering Research Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China",
        "Eye Public Health Research Center, School of Medicine, Tongji University, Shanghai, China"
      ],
      "name": "Linlin Du"
    },
    {
      "affiliations": [
        "Shanghai Eye Diseases Prevention &Treatment Center/ Shanghai Eye Hospital, School of Medicine, Tongji University, Shanghai, China",
        "National Clinical Research Center for Eye Diseases, Shanghai, China",
        "Shanghai Engineering Research Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China",
        "Eye Public Health Research Center, School of Medicine, Tongji University, Shanghai, China"
      ],
      "name": "Jinliuxing Yang"
    },
    {
      "affiliations": [
        "Shanghai Eye Diseases Prevention &Treatment Center/ Shanghai Eye Hospital, School of Medicine, Tongji University, Shanghai, China",
        "National Clinical Research Center for Eye Diseases, Shanghai, China",
        "Shanghai Engineering Research Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China",
        "Eye Public Health Research Center, School of Medicine, Tongji University, Shanghai, China"
      ],
      "name": "Jianfeng Zhu"
    },
    {
      "affiliations": [
        "Shanghai Eye Diseases Prevention &Treatment Center/ Shanghai Eye Hospital, School of Medicine, Tongji University, Shanghai, China",
        "National Clinical Research Center for Eye Diseases, Shanghai, China",
        "Shanghai Engineering Research Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China",
        "Eye Public Health Research Center, School of Medicine, Tongji University, Shanghai, China"
      ],
      "name": "Wei Gao"
    },
    {
      "affiliations": [
        "Shanghai Eye Diseases Prevention &Treatment Center/ Shanghai Eye Hospital, School of Medicine, Tongji University, Shanghai, China",
        "National Clinical Research Center for Eye Diseases, Shanghai, China",
        "Shanghai Engineering Research Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China",
        "Eye Public Health Research Center, School of Medicine, Tongji University, Shanghai, China"
      ],
      "name": "Haidong Zou"
    },
    {
      "affiliations": [
        "The Hong Kong Polytechnic University, Hong Kong, Hong Kong SAR, Hong Kong"
      ],
      "name": "Mingguang He"
    },
    {
      "affiliations": [
        "National Clinical Research Center for Eye Diseases, Shanghai, China"
      ],
      "name": "Xun Xu"
    },
    {
      "affiliations": [
        "Shanghai Eye Diseases Prevention &Treatment Center/ Shanghai Eye Hospital, School of Medicine, Tongji University, Shanghai, China",
        "National Clinical Research Center for Eye Diseases, Shanghai, China",
        "Shanghai Engineering Research Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China",
        "Eye Public Health Research Center, School of Medicine, Tongji University, Shanghai, China"
      ],
      "name": "Xiangui He"
    }
  ],
  "title": "Time outdoors prevents myopia in hyperopic children, but protection is weaker in premyopic children: a post-hoc analysis of a cluster-randomised trial",
  "uid": "dc5bcd77-9ddf-5d6f-845b-beeb1a02df8f"
}