Data was collected from the 2008-12 KNHANES survey and the study included 7695 of 9351 subjects with refractive data. The mean age was 11.8 years (5-20 range) with 48.2% female. Mean spherical equivalent was -1.82 ±2.23D. For five-year-olds, the mean spherical equivalent (SE) was +0.04 ±0.86D; for 20-year-olds -2.88 2.68D. Therefore mean refractive change of -2.92D was shown as the rate of change from five to 20 years equating to -0.19D per year. The total refractive change of the 90th percentile group was approximately six times more than that of the 10th percentile group between five and 20 years. The authors suggest younger patients in higher percentile groups for myopia warrant careful observation and may be candidates for treatment to prevent myopia regression. They acknowledge limitations of this study including cross section design. A cohort study is needed to monitor refractive change. Refractive data was non-cycloplegic, thus data might be more myopic than actually recorded.