Progression of myopia in children and teenagers: a nationwide longitudinal study

BACKGROUND: Data on myopia prevalence and progression in European children are sparse. The aim of this work was to evaluate the progression of myopia in children and teenagers in a large prospective study. METHODS: A prospective study involving a nationwide cohort. Myopia was defined as a spherical equivalent (SE) of ≤ -0.50 diopters (D). Data on refractive error, gender and age were collected in 696 optical centres in France between 2013 and 2019, including 136 333 children (4-17 years old) in the analysis.Progression of myopia was assessed between the first visit and the last visit over up to 6.5 years. RESULTS: Mean age was 11.3±3.8 years (55.0% of female). The proportion of children progressing more than -0.50 D per year was higher in age groups 7-9 years and 10-12 years and in children with SE ≤ -4.00 D at first visit, representing 33.1%, 29.4% and 30.0% of these groups, respectively. In multivariate analysis, progression during the first 11-24 months was higher in the 7-9 and 10-12 age groups (-0.43 D and -0.42 D, respectively), for higher SE at baseline (at least -0.33 D for SE ≤ -1 D) and for girls (-0.35 D). CONCLUSION: This is the first French epidemiological study to investigate myopia progression in a large-scale cohort of children. Sex, age groups and myopia severity are associated with differing rates of progression.