Outdoor time: a protective measure against myopia prevalence?
In this article:
The combined evidence from studies included in this review suggest that increasing outdoor time can have an inverse influence on the prevalence of myopia. It is possible it may also have an effect on slowing myopia progression, but further research is needed to confirm this relationship and objectively determine the optimum daily exposure needed to achieve this
Paper title: The Role of Time Exposed to Outdoor Light for Myopia Prevalence and Progression: A Literature Review
Authors: Eppenberger, Leila Sara;1 Sturm, Veit1,2
- Department of Health Sciences & Technology, ETH, Zurich, Switzerland
- Eye Department, Cantonal Hospital, St. Gallen, Switzerland
Date: July 2020
Reference: Eppenberger LS, Sturm V. The Role of Time Exposed to Outdoor Light for Myopia Prevalence and Progression: A Literature Review. Clin Ophthalmol. 2020 Jul 2; 14:1875-1890.
Summary
The association between the time children spend outside and the incidence and progression of myopia has been examined in several studies as a potential preventative treatment1, where natural light has been shown to inversely influence the onset and progression of myopia.
The authors selected twelve studies published within the last ten years to critically review the evidence for this association and discover if outdoor time was protective in reducing the impact of myopia.
They found that although there were inherent differences in the study methodologies, the majority showed that increasing outdoor time decreased the prevalence of myopia in children.
Further research using objective methods to measure natural light exposure will help establish if a dose-response exists for influencing myopia progression, especially for children who are already myopic.
What does this mean for my practice?
Although there were inherent differences in the study methodologies, the majority of the featured studies showed that increasing outdoor time decreased the prevalence of myopia in children.
- This review has shown that spending more time outdoors could be a valuable measure in protecting children from developing myopia and that progression could be slowed to an extent by time spent outdoors.
- Time outdoors may also have a protective effect in delaying or preventing myopia onset.
Eye care practitioners can relay this information to children and parents and encourage outdoor play time to be part of children’s lifestyles. Outdoor time can be incorporated into an overall myopia management plan.
This recent study explains the importance of encouraging outdoor time for children.
What do we still need to learn?
The studies in this review primarily used questionnaires to assess children's outdoor time, but some only gathered this information once, potentially missing changes in habits. Questionnaires can be subject to recall bias, and one study used light meters to address this issue.
Future research employing objective methods, like light meters, could establish a more accurate dose-response relationship and its impact on myopia reduction. Many studies had short observation periods, limiting the ability to capture myopic changes within a year.
Since most studies focused on Asian countries, extrapolating findings to countries with different myopia prevalence is challenging. Repeating investigations in diverse settings could confirm these findings.
The inability to perform a meta-analysis due to varied methodologies and outcome measures across studies complicates combining results. Confounding factors like parental myopia and near work were controlled to varying extents, leaving uncertainty about the specific role of outdoor time in reducing myopia prevalence.
Abstract
Title: The Role of Time Exposed to Outdoor Light for Myopia Prevalence and Progression: A Literature Review
Authors: Leila Sara Eppenberger, Veit Sturm
Purpose: The development of myopia as a refractive disorder seems to hold multifactorial causes. Among others, increased time exposed to natural light outdoors is regarded as possible effective preventive measure against myopia development. The objective of this review is to analyse and summarize the evidence investigating the association between time outdoors and myopia prevalence and progression
Methods: A review, restricted to articles published in the last ten years, was conducted. The literature search for the included articles was performed in the following databases: PubMed, the Cochrane Library, Web of Science and Scopus. If predefined inclusion criteria were met, the studies were further categorized and data were summarized and individually evaluated.
Results: Two cross-sectional studies, 7 prospective cohort studies and 3 intervention studies were reported in this review, representing the data of a total of 32,381 participants. The majority of the studies found an inverse association between myopia incidence/prevalence and increased time outdoors. The association between time outdoors and myopia progression on the other hand remains debatable; one recent randomized controlled trial indicating a protective value of increased time outdoors for further progression in myopic children.
Conclusions: In summary, increasing time exposed to outdoor light seems to be a simple and effective preventive measure to decrease myopia prevalence. Also, contrasting previous review work, it may represent a potential strategy for myopia progression control. Future investigation is necessary to better define and quantify outdoor time and its effects on myopia
Meet the Authors:
About Ailsa Lane
Ailsa Lane is a contact lens optician based in Kent, England. She is currently completing her Advanced Diploma In Contact Lens Practice with Honours, which has ignited her interest and skills in understanding scientific research and finding its translations to clinical practice.
Read Ailsa's work in the SCIENCE domain of MyopiaProfile.com.
References
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