Analysis of Refractive Error and Corneal Asphericity in Elementary School Students in Ilsan City

ABSTRACT

PURPOSE: To determine the relationships among refractive error, corneal asphericity, and axial length in elementary school students. METHODS: One hundred eleven eyes from 56 subjects were included in this study. All subjects underwent cycloplegic refraction corrected to the spherical equivalent. Axial length was measured, and corneal topography was performed. Corneal asphericity was assessed using eccentricity (e) calculated according to the formula Q=-e2. The relationship among spherical equivalent, asphericity, and axial length was determined using a linear regression model. RESULTS: Subjects were between 8 and 12 years of age (mean, 9.99+/-1.33). The average spherical equivalent was -1.38+/-2.08D (-7.13~2.63D), the average axial length was 23.84+/-1.17 mm (20.10~26.37 mm), and the average corneal asphericity was -0.29+/-0.10 (-0.55~-0.07). An increase in myopia was positively correlated with an increase in axial length (p<0.0001). The degree of myopia was negatively associated with corneal asphericity (p=0.019). An increase in axial length was related to an increase of negativity in asphericity (p=0.012). CONCLUSIONS: An increase in myopia was correlated with an increase in axial length. As the degree of myopia and axial length increased, corneal asphericity became more prolate. A longitudinal study with more subjects is required to validate these results.