Careful planning of green space development may be a strategy for myopia prevention, researchers suggest. Photo: Artem Kniaz on Unsplash.

Regularly spending time outdoors during childhood is now well accepted to be a bulwark against myopia development. Do the specific characteristics of the environs play a role? Previous studies have suggested that green space exposure reduces the risk of myopia, but the association between the two poorly understood. In a new JAMA Ophthalmology study, Chinese researchers used quantitative data from high-resolution satellite imaging to evaluate this association and found a reduced risk of myopia among primary school students studying at campuses with a larger greenness proportion and larger areas of green space.

A total of 138,735 students in first through fourth grades (ages six to nine) in China were included. Baseline data was collected in 2016 through 2017, and students were followed up in 2018 through 2019. Data was analyzed from September 2020 to January 2022. The study used satellite images to document the proportion, aggregation and connectivity of green space, all of which were found to be associated with two-year changes in school myopia rate.

The authors found a reduced risk of myopia among primary school students studying at campuses with a larger greenness proportion, larger areas of green space, better connectivity between green patches, more aggregated green space, less fragmented green space and shorter distance between patches. Analysis of seven relevant landscape metrics demonstrated an association with smaller increases in school myopia prevalence and incident myopia at the individual level, suggesting that the landscape structure as a whole was negatively associated with myopia development, the authors noted.

“We believe that these underlying green space morphological characteristics, which were not captured in previous studies, could be informative for population-based urban planning strategies to prevent myopia,” the authors wrote in their paper for the journal.

Structure of green space was associated with a decreased relative risk of myopia, which may provide guidance for construction and renovation of schools, the authors suggested. “A well-arranged green space with larger areas, better connectivity, increased aggregation, lower fragmentation and shorter distance between patches was correlated with slower progression in school myopia prevalence,” the authors explained.

Additionally, by creating a more inviting environment, higher proportion and higher aggregation may provide greater incentives for exposure to outdoor light, proven to protect against the development of myopia, the authors suggested.

“Furthermore, a higher proportion of green space might also encourage children remaining indoors to focus on distant targets and reduce persistent and intense near work. Continuous near-work is well understood as a risk factor for myopia,” the authors noted. “In addition, our results suggest that more connected green space, such as greenways, might increase the accessibility of green space and provide a more effective myopia control option.”

Yang Y, Liao H, Zhao L, et al. Green space morphology and school myopia in China. JAMA Ophthalmology. January 4, 2024. [Epub ahead of print.]