To investigate the degree, distribution, and change in refractive error in the pediatric population 5 to 20 years of age.

We collected data from 7,695 subjects aged 5 to 20 years who participated in the Korean National Health and Nutrition Examination Survey from 2008 to 2012. Non-cycloplegic refractive error was measured using an autorefractor. Mean spherical equivalent calculated from the measured refractive error data in both eyes was used. The subjects were categorized into mild, moderate, or high refractive abnormality or emmetropia according to the degree of refractive error. The degree and distribution of refractive error in all subjects and age-matched subjects were analyzed. The change in refractive error was analyzed according to age.

Mean refractive error of the study subjects was -1.82 diopters. As subject age increased, myopia increased from +0.04 diopters at 5 years of age to -2.88 diopters at 20 years of age. Myopia was observed in 66.2% of subjects and accounted for only 18.5% of the 5-year-old subjects, but increased to 84.3% in the 20-year-old subjects. The rate among all study subjects was -0.19 diopters per year. The greatest myopic progression rate (-0.46 diopters per year) among all age groups was in subjects 7 to 9 years of age. Myopic progression continued until 16 years of age.

The ratio of pediatric myopia subjects between 5 and 20 years of age was high in Korea. The rate of myopic progression was the fastest in subjects 7 to 9 years of age. After 16 years of age, myopic change paused.