Increased exposure to outside light tied to reduced risk of incident myopia: Study

Outdoor light exposure is considered a safe and effective strategy to reduce myopia development and aligns with existing public health initiatives to promote healthier lifestyles in children. However, it is unclear whether this strategy reduces myopia progression in eyes that are already myopic. This study aims to conduct an overview of systematic reviews (SRs) reporting time spent outdoors as a strategy to prevent myopia or slow its progression in children.

They searched the Cochrane Library, EMBASE, MEDLINE and CINAHL from inception to 1 November 2020 to identify systematic reviews (SRs) that evaluated the association between outdoor light exposure and myopia development or progression in children. Outcomes included incident myopia, prevalent myopia and change in spherical equivalent refraction (SER) and axial length (AL) to evaluate annual rates of myopia progression. The methodological quality and risk of bias of included SRs were assessed using the AMSTAR-2 and ROBIS tools, respectively.

The results of the study are:

Seven systematic reviews (SRs) were identified, which included data from 47 primary studies with 63,920 participants. Pooled estimates (risk or odds ratios) consistently demonstrated that time outdoors was associated with a reduction in prevalence and incidence of myopia. In terms of slowing progression in eyes that were already myopic, the reported annual reductions in spherical equivalent refraction (SER) and axial length (AL) from baseline were small (0.13–0.17 D) and regarded as clinically insignificant. Methodological quality assessment using AMSTAR-2 found that all reviews had one or more critical flaws and the ROBIS tool identified a low risk of bias in only two of the included systematic reviews (SRs).

Thus, this overview found that increased exposure to outdoor light reduces myopia development. However, based on the annual change in spherical equivalent refraction (SER) and axial length (AL), there is insufficient evidence for a clinically significant effect on myopia progression. The poor methodological quality and inconsistent reporting of the included systematic reviews reduce confidence in the estimates of effect.

Reference:

Time spent outdoors as an intervention for myopia prevention and control in children: an overview of systematic reviews by Rohit Dhakal, et al. published in the Ophthalmic and Physiological Optics.

https://onlinelibrary.wiley.com/doi/10.1111/opo.12945

Keywords:

Increased exposure, outdoor light, prevention, incident myopia, benefit, myopia progression, uncertain, Time spent outdoors, intervention, children, Ophthalmic and Physiological Optics, Rohit Dhakal, Rakhee Shah, Byki Huntjens, Pavan K Verkicharla, John G Lawrenson