Greater green space was associated with a lower risk of myopia in elementary school children

Chinese scientists conducted a study using satellite imagery and found that a higher proportion of green space in a city was associated with a lower prevalence of myopia in younger schoolchildren. As reported in JAMA Ophthalmology, it decreased by one and a half percent when the area of plantings increased by ten percent.

Myopia, or nearsightedness, is considered a serious public health problem worldwide. The number of people with myopia is projected to increase to nearly five billion by 2050, among whom 20 percent will have high myopia. Scientists believe that urbanization has led to a significant increase in the proportion of people with myopia, especially among children. Children living in areas with large areas of green space are known to be less likely to wear glasses. Potentially, increasing the area of green space near schools could improve the prevention of clinical refractive disorders.

Yahan Yang and colleagues from the Guangdong Provincial Eye Disease Clinical Research Center investigated the relationship between green space morphology and myopia in school-going children. To do so, they used satellite images of green spaces in and around school grounds, for which they calculated a vegetation index to show the degree of greenness of the area.

Between September 2016 and June 2017, a total of 149075 elementary school students completed the baseline assessment in 110 participating schools. Of these, 115350 were followed up two years later. The average increase in prevalence of myopia was 21.2 percent; of the 101897 schoolchildren who did not have myopia at baseline, 26292 developed it. When green space was increased by ten percent, myopia prevalence fell by 1.5 percent over two years (p = 0.006). And when the vegetation index was increased by 0.1 units, the prevalence of myopia fell by 1.7 percent.

These data show that the right urban device policy regarding green spaces can be the basis for the prevention of myopia in young schoolchildren. In the future, scientists plan to find out whether green spaces have the same effect in other age groups, as well as the direct mechanism of this phenomenon.

However, not only schoolchildren, but also university students are at risk of becoming myopic. British researchers found that each additional year of education after 16 years of age leads to a decrease in the optical power of the eye by 0.27 dioptres.