Characteristics of refraction and ocular biometric parameters of junior and senior school students in Deqing County, Zhejiang Province

Abstract

Objective To assess the characteristics of the ocular biometric parameters and prevalence of refractive errors in junior and senior school children in Deqing County. Methods Investigative survey. There were 1853 students from 6 schools in Deqing County randomly recruited for the study. Their mean age was (14.4±3.1)years; 47.81％ were females and 52.19％ were males.Objective refraction without cycloplegia was obtained with an autorefractor. Axial length (AL), anterior chamber depth (ACD) and corneal curvature (CC) were measured by IOL Master under noncycloplegia.Data were analyzed with an independent samples t test, a paired t test, one-way ANOVA and linear regression. Results The prevalence of myopia and astigmatism of the 1853 students was 82.60％ and 10.50％, respectively. Average spherical equivalent (SE) and cylinder power of right eyes were (-2.38±2.12) and (-0.51±0.49)D, respectively. Mean AL and ACD of right eyes were (24.3±1.2) and (3.6± 0.2)mm, respectively. Average horizontal and vertical CC were (42.78±1.51) and (43.81±1.52)D,respectively. The relationship between anterior segment (AS) and posterior segment (PS) during axial elongation was PS=1.66×AS+14.78. Conclusion The prevalence of myopia is higher in elder students from Deqing County schools, and there is a rapid rise of prevalence of myopia since 9-year-old children. Corneal curvatures significantly correlate to sex, but not to age or refractive state. As the level of myopia increase, ACD becomes deeper and AL elongates, during which posterior segment of eye plays a predominant role. Key words: Refraction,ocular; Myopia; Ocular biometric parameters; Small-area analysis; Data collection