Time trend of axial length and associated factors in 4- and 5-year-old children in Shanghai from 2013 to 2019

Tao Li,Xiaodong Zhou,Huihong Qi,Man She,Xiaoqian Yao,Ting Wan,Xuefeng Chen,Qianqian Hu

doi:10.1007/s10792-020-01637-5

Abstract

PurposeTo evaluate the time trend of axial length (AL) and associated factors in 4- and 5-year-old children in Shanghai from 2013 to 2019.MethodsThis was a 7-year observational study of 985 four-year-old and 1059 five-year-old children in Shanghai. AL, horizontal and vertical corneal curvature, spherical equivalent (SE), and body height and weight were measured. Furthermore, a questionnaire was collected, including time outdoors and bad eyesight habits.ResultsIn 4-year-old children, no significant difference was found in AL (P = 0.526), but significant differences were observed in SE (P = 0.001), horizontal corneal curvature (P = 0.006), vertical corneal curvature (P = 0.004), height (P < 0.001), and weight (P = 0.022) from 2013 to 2019. In 5-year-old children, no significant differences were found in AL (P = 0.304), SE (P = 0.200), or weight (P = 0.292), but significant differences were observed in horizontal corneal curvature (P = 0.040), vertical corneal curvature (P = 0.015), and height (P < 0.001) from 2013 to 2019. Multivariate analyses revealed that AL was mainly significantly associated with boys and time outdoors in the 4- and 5-year-old children.ConclusionsThe AL of 4- and 5-year-old children remained relatively stable in Shanghai from 2013 to 2019. Longitudinal studies are needed to confirm the relationship between AL elongation and environmental risk factors.

Highlights

Myopia, which is the result of a mismatch between the axial length (AL) and ocular refractive power, has become a major public health issue worldwide [1]
Multivariate analyses revealed that AL was mainly significantly associated with boys and time outdoors in the 4- and 5-year-old children
The purpose of this study is to evaluate the time trend of AL in 4- and 5-year-old children, and to assess potential factors associated with AL in these children in a kindergarten in Shanghai from 2013 to 2019

Summary

Introduction

Myopia, which is the result of a mismatch between the axial length (AL) and ocular refractive power, has become a major public health issue worldwide [1]. AL is an important anatomic parameter for the optics of the eye, determining the refraction. The AL may be the primary factor for the eventual development of myopia-related visual impairment complications, such as retinal detachment, optic disc abnormalities, myopic macular degeneration, and choroidal neovascularization [2,3,4]. Despite the importance of AL, few population-based studies have focused on AL, especially in preschool children [7,8,9,10,11,12]. The purpose of this study is to evaluate the time trend of AL in 4- and 5-year-old children, and to assess potential factors associated with AL in these children in a kindergarten in Shanghai from 2013 to 2019

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Methods

Results

Conclusion