Establishment of Main Refractive Parametric Regression Models in Schoolchildren Aged 3 to 12 Years

Objective: To establish a correlation model between static refraction and the main refractive parameters of children aged 3-12 years. Methods: This cross sectional study was divided into two parts. In part one, in Changsha Aier Eye Hospital from July 2014 to June 2016, 245 children were randomly selected and measurements were taken of their axial length (AL), corneal curvature (Km) and anterior chamber depth, spherical equivalent refractive (SE) and calculated lens power (LP). The correlations between refraction and the refractive parameters were analyzed to establisha correlative mathematical model. In part two, in Changsha Aier Eye Hospital from July to December 2016, 43 children were randomly selected to measure the above refractive parameters and their cycloplegic refraction (SEmeasured). The lens power and static refraction (SEcalculated) were calculated. The consistency between SEmeasured and SEcalculated was compared by Bland-Altman analysis. Results: The correlation model was established as follows: The correlation coefficients between SE and AL, Km and LP were -0.95, -0.83 and -0.62, respectively (all P<0.001). SE=110.56-2.51×AL-0.97×Km-0.44×LP (R2=0.95, F=2534.52, P<0.001). There was a significant correlation between SEmeasured and SEcalculated (r=0.97, P<0.001), the 95% limit of agreement was -1.00-0.63 D, average error was -0.19 D (95% consistency limit: -0.28 to -0.10 D), and 81.40% of the data points were within the clinically acceptable range (-0.55 to 0.55 D). Conclusions: The axial length is the most important factor in refraction besides corneal curvature and lens power. The refraction correlation model can accurately estimate the static refraction of children from 3 to 12 years old. Key words: refraction; axial length; corneal power; lens power; correlation model