Abstract
BackgroundTo determine the change in refractive error and the incidence of myopia among school-aged children in the Yongchuan District of Chongqing City, Western China.MethodsA population-based cross-sectional survey was initially conducted in 2006 among 3070 children aged 6 to 15 years. A longitudinal follow-up study was then conducted 5 years later between November 2011 and March 2012. Refractive error was measured under cycloplegia with autorefraction. Age, sex, and baseline refractive error were evaluated as risk factors for progression of refractive error and incidence of myopia.ResultsLongitudinal data were available for 1858 children (60.5%). The cumulative mean change in refractive error was −2.21 (standard deviation [SD], 1.87) diopters (D) for the entire study population, with an annual progression of refraction in a myopic direction of −0.43 D. Myopic progression of refractive error was associated with younger age, female sex, and higher myopic or hyperopic refractive error at baseline. The cumulative incidence of myopia, defined as a spherical equivalent refractive error of −0.50 D or more, among initial emmetropes and hyperopes was 54.9% (95% confidence interval [CI], 45.2%–63.5%), with an annual incidence of 10.6% (95% CI, 8.7%–13.1%). Myopia was found more likely to happen in female and older children.ConclusionsIn Western China, both myopic progression and incidence of myopia were higher than those of children from most other locations in China and from the European Caucasian population. Compared with a previous study in China, there was a relative increase in annual myopia progression and annual myopia incidence, a finding which is consistent with the increasing trend on prevalence of myopia in China.
Highlights
The prevalence of myopia has been reported to be higher among East Asians and those living in urban locations, such as Singapore, Hong Kong, Taiwan, Japan, and Korea, than among European Caucasians and those living in rural areas.[16,17,22,23,24,25]
Eleven of the 1869 children with follow-up examinations were excluded from refractive error analyses because of ocular pathology or inadequate cycloplegic dilation
In logistic regression modeling of myopia incidence with age and sex as covariates, we found that females had significantly greater odds of incident myopia and that increasing age was positively correlated with increased incidence of myopia
Summary
It is well known that refractive error, especially myopia, is a common cause of visual impairment in children.[1,2] In the past few decades, numerous cross-sectional studies have provided information on the pattern of prevalence and risk factors for myopia in children.[3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21] These studies have shown that the prevalence of refractive error varies widely, depending on geography, ethnicity, sex, and age. To determine the change in refractive error and the incidence of myopia among school-aged children in the Yongchuan District of Chongqing City, Western China. Methods: A population-based cross-sectional survey was initially conducted in 2006 among 3070 children aged 6 to 15 years. Sex, and baseline refractive error were evaluated as risk factors for progression of refractive error and incidence of myopia. The cumulative mean change in refractive error was −2.21 (standard deviation [SD], 1.87) diopters (D) for the entire study population, with an annual progression of refraction in a myopic direction of −0.43 D. Myopic progression of refractive error was associated with younger age, female sex, and higher myopic or hyperopic refractive error at baseline. Conclusions: In Western China, both myopic progression and incidence of myopia were higher than those of children from most other locations in China and from the European Caucasian population. Compared with a previous study in China, there was a relative increase in annual myopia progression and annual myopia incidence, a finding which is consistent with the increasing trend on prevalence of myopia in China
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