Urban environment may influence myopia development in children, study finds

It appears that factors specific to the urban environment may increase the risk of myopia in children, a large study found.

"This association was found to be independent of conventional myopia risk factors such as ethnicity, parental myopia, the levels of near work and outdoor activity," the study authors said in the September issue of Investigative Ophthalmology & Visual Science.

Jenny M. Ip, MBBS, and colleagues used questionnaire responses obtained from 2,309 Australian 12-year-old children and their parents to examine the relationship between myopia and urbanization. The surveys, which differed for children and parents, included questions concerning sociodemographic and environmental issues, including parental education, ethnicity, and duration of near work and outdoor activity.

The investigators used population density data from the Sydney area to construct five urban regions, ranging from outer suburban to inner city.

After adjusting for age, sex, ethnicity, near work, outdoor activity and parental myopia, the investigators found the lowest myopia prevalence in the outer suburban region (6.9%) and the highest myopia prevalence in the inner city region (17.8%).

According to multivariate-adjusted analyses, children living in regions with higher population densities were at greater risk of myopia (P = .0001), the authors noted.

After adjusting for ethnicity, near work and outdoor activity, the investigators identified a higher myopia prevalence among children living in apartment residences than in other housing types.

Housing density, which was calculated as the number of houses visible from a front door, was not significantly linked with myopia, according to the study.

Myopia was most prevalent in the inner city region among European Caucasian children (8.1%) and East Asian children (55.1%), the authors noted.