Analysis on Transitional Change of Refractive Error Distributions in Pediatric Population Using KNHANES

Purpose: To investigate transitional changes in refractive error distributions in a pediatric population using the Korean National Health and Nutrition Examination Survey (KNHANES) data. Methods: We investigated 7,181 subjects from the 4th and 5th (2008-2012) KNHANES and 1,225 subjects from the 7th (2016) KNHANES; all subjects were 5 to 18 years of age. We used the average spherical equivalent (SE) of both eyes calculated with noncycloplegic refractive errors measured via autorefractor. We determined SE percentiles by age in order from hyperopia to myopia. We acquired the mean SE by age. We investigated the proportions of subjects with mild, moderate, and severe refractive errors by age. Results: Mean refractive errors were -1.73 +/- 2.16 diopters in subjects in the 4th and 5th KNHANES and -1.66 +/- 2.21 diopters in subjects in the 7th KNHANES; these were not significantly different between the two groups (p = 0.071). Mean refractive errors were more myopic in subjects in the 4th and 5th than in subjects in the 7th KNHANES only at 8 and 9 years of age (p = 0.018, p = 0.026). The distribution of percentiles by age was similar between the two groups. The respective proportions of hyperopia, emmetropia, and myopia were 6.2%, 27.6%, and 66.2% in subjects in the 4th and 5th survey, and 7.3%, 29.7% and 63.0% in subjects in the 7th survey. There was no significant difference in refractive error proportion between the 2 groups (p = 0.326). Conclusions: There was no definite transitional change of refractive error distributions between the two KNHANES groups. However, additional periodic surveys are needed to confirm this hypothesis.