Relationship between myopia and AL/CR ratio in children of 7-12 years old

Abstract:

Objective：To investigate the relationship between axis length/corneal radius of curvature ratio（AL/CR ratio） and myopia degree in children of 7-12years old. Methods：Data of spherical equivalent refraction，axial length and corneal refractive power from 402 children（804 eyes） of 7-12 years old were obtained by cycloplegic optometry and IOL-Master and AL/CR ratio was calculated. According to the spherical equivalent refraction，402 children were divided into three groups：mild myopia group，moderate myopia group and high myopia group. Statistics were analyzed by SPSS 22.0 software. Results：AL/CR ratio among high myopia group（3.47±0.13），moderate myopia group（3.26±0.09） and mild myopia group（3.12±0.07） was significantly different（F=972.220，P=0.000）. Correlation between spherical equivalent refraction and AL/CR ratio was higher than that between axial length and corneal radius of curvature（r=-0.886，r=-0.752，r=0.243，P=0.000）. According to the linear regression，spherical equivalent refraction was changed about-15.2D with each increase of AL/CR ratio（r2=78.4%，P=0.000）. Among those three groups，difference of linear regression line between axial length and corneal radius of curvature had no statistical significance（r2=48.1%，r2=50.9%，r2=16.7%，P=0.000），but dif－ference of the linear regression line between AL/CR ratio and spherical equivalent refraction had statistical significance（r2=20.5%，r2=19.5%，r2=84.0%，P=0.000）. Conclusion：AL/CR ratio is an objective index in the diagnosis of myopia and can be used to clas－sify different degrees of myopia.