Guangdong cohort finds substantial myopia burden among school-aged children

Researchers used data from a student health surveillance programme in Guangdong Province to estimate myopia prevalence and incidence among people aged 6–19 years. The prospective cohort included 197,685 participants (mean age 10.82 years; 52.67% boys). Myopia was defined by both uncorrected visual acuity below 5.0 and spherical equivalent below −0.50 diopters in either eye; high myopia was defined as spherical equivalent below −6.00 D in at least one eye. Estimates were age-standardized to the 7th National Census population.

At baseline, crude myopia prevalence was 45.64%, compared with an age-standardized prevalence of 55.14%. High-myopia prevalence was 3.27% crude and 5.13% age-standardized. Over five years, 32,012 new screening-defined cases were identified. The age-standardized cumulative incidence was 28.00%, and the incidence rate was 77.98 cases per 1,000 person-years. Girls, children aged 6–9 years, students in grades 4–9, and urban students had higher incidence; students from minority ethnic groups had lower risk.

The large cohort provides estimates for one province, not necessarily for all children in China or elsewhere. The findings identify groups with higher incidence but do not test whether school-based prevention strategies reduce myopia.