Age-Related Change of Axial Length, Spherical Equivalent, and Prevalence of Myopia and High Myopia in School-Age Children in Shanghai: 2014–2018

Tao Li,Bo Jiang,Xiaodong Zhou

doi:10.1155/2020/4235893

Abstract

Purpose. To investigate the age-related change of axial length (AL), spherical equivalent (SE), and prevalence of myopia and high myopia in children at 7–18-year-olds in Shanghai in 2014 and 2018, respectively. Methods. This was an observational study in Shanghai. The same 3 schools were selected in 2014 and 2018, respectively. AL, SE, prevalence of myopia and high myopia, height, and weight were measured. A questionnaire regarding the lifestyles was completed. Results. Mean age was smaller in 2018 than in 2014 (P<0.001), and mean AL was shorter in 2018 than in 2014 (P=0.003), whereas mean SE was greater in 2018 than in 2014 (P<0.001). The prevalence of myopia and high myopia was lower in 2018 than in 2014 (P<0.001andP=0.013, respectively). Mean AL increased with age from 7-year-olds to 18-year-olds in 2014 and 2018 (bothP<0.001), respectively. Mean SE decreased with age in 2014 and 2018 (bothP<0.001), respectively. The prevalence of myopia and high myopia increased with age in 2014 and 2018 (allP<0.001), respectively. Less mean time outdoors and more mean time of study of all children were observed in 2018 than in 2014 (P=0.018andP<0.001, respectively). Conclusion. This study shows normative growth values for AL and SE in Shanghai children at the age of 7–18-year-olds, as well as the age-specific prevalence of myopia and high myopia.

Highlights

Myopia is the most common eye disorder worldwide [1,2,3], which is mainly caused by a mismatch between the optical power of the eye and its excessively long axial length (AL).e correction modalities for myopia include spectacle lenses [4], contact lenses [5], photorefractive keratectomy [6], laser epithelial keratomileusis [7], laser in situ keratomileusis (LASIK) [7], femtosecond laser-assisted LASIK [8], small-incision lenticule extraction (SMILE) [8], and Visian implantable collamer lens (ICL) implantations [9]
Due to the excessive axial elongation, high myopia can increase the risk of visual impairment complications [1, 10, 11], which can lower life satisfaction and reduce the quality of life [12, 13]. us, the control of myopia progression has become very essential
The mechanism of myopia development is still unclear, myopia is the result of genetic and environmental factors. e prevalence of myopia and high myopia is relatively high in East and Southeast Asian regions [14,15,16,17], partly due to increasing environment risk factors. e changing lifestyles [17, 18] and classical risk factors are associated with the increased risk of progression of myopia in school-age children

Summary

Introduction

Myopia is the most common eye disorder worldwide [1,2,3], which is mainly caused by a mismatch between the optical power of the eye and its excessively long axial length (AL). E prevalence of myopia and high myopia is relatively high in East and Southeast Asian regions [14,15,16,17], partly due to increasing environment risk factors. E changing lifestyles (e.g., time outdoors and time of study) [17, 18] and classical risk factors (e.g., education [19, 20] and ethnicity [3]) are associated with the increased risk of progression of myopia in school-age children. Updating the age-related change trends of myopia-related data in childhood is very important for myopia prevention and controlling. We conducted this study to investigate age-related change trends for AL, SE, and prevalence of myopia and high myopia in children at 7–18-year-olds in Shanghai in 2014 and 2018, respectively. We investigated whether these differences between 2014 and 2018 could be explained by the time outdoors and time of study

Methods

Primary school Junior high school Senior high school

Findings

Senior high school