Evolution of the Prevalence of Myopia among Taiwanese Schoolchildren
Authors: Tzu-Hsun Tsai, Yao-Lin Liu, I-Hsin Ma, Chien-Chia Su, Chao-Wen Lin, Luke Long-Kuang Lin, Chuhsing Kate Hsiao, I-Jong Wang
Journal: Ophthalmology (2020)

PurposeThe aim of this study was to evaluate the changes in the prevalence of myopia in Taiwanese schoolchildren over the past few decades and to analyze the risk factors for myopia.DesignAnalysis of 8 consecutive population-based myopia surveys conducted from 1983 through 2017.ParticipantsAn average of 8917 (5019–11 656) schoolchildren 3 to 18 years of age were selected using stratified systematic cluster sampling or by probability proportional to size sampling.MethodsAll participants underwent complete ophthalmic evaluations. Three drops of 0.5% tropicamide were used to obtain the cycloplegic refractive status of each participant. Questionnaires were used to acquire participant data from the 1995, 2005, 2010, and 2016 surveys.Main Outcome MeasuresPrevalence of myopia (spherical equivalence of ≤−0.25 diopter [D]) and high myopia (≤−6.0 D) was assessed. Multivariate analyses of risk factors were conducted.ResultsThe prevalence of myopia among all age groups increased steadily. From 1983 through 2017, the weighted prevalence increased from 5.37% (95% confidence interval [CI], 3.50%–7.23%) to 25.41% (95% CI, 21.27%–29.55%) for 7-year-olds (P = 0.001 for trend) and from 30.66% (95% CI, 26.89%–34.43%) to 76.67% (95% CI, 72.94%–80.40%) for 12-year-olds (P = 0.001 for trend). The prevalence of high myopia also increased from 1.39% (95% CI, 0.43%–2.35%) to 4.26% (95% CI, 3.35%–5.17%) for 12-year-olds (P = 0.008 for trend) and from 4.37% (95% CI, 2.91%–5.82%) to 15.36% (95% CI, 13.78%–16.94%) for 15-year-olds (P = 0.039 for trend). In both the 2005 and 2016 survey samples, children who spent less than 180 minutes daily on near-work activities showed significantly lower risks for myopia developing (<60 minutes: odds ratio [OR], 0.48 and 0.56; 60–180 minutes: OR, 0.69 and 0.67). In the 2016 survey, spending more than 60 minutes daily on electronic devices was associated significantly with both myopia and high myopia (OR, 2.43 and 2.31).ConclusionsThe prevalence of myopia among schoolchildren increased rapidly from 1983 through 2017 in Taiwan. The major risk factors are older age and time spent on near-work activities. Use of electronic devices increased the amount of time spent on near-work and may increase the risk of developing myopia. The aim of this study was to evaluate the changes in the prevalence of myopia in Taiwanese schoolchildren over the past few decades and to analyze the risk factors for myopia. Analysis of 8 consecutive population-based myopia surveys conducted from 1983 through 2017. An average of 8917 (5019–11 656) schoolchildren 3 to 18 years of age were selected using stratified systematic cluster sampling or by probability proportional to size sampling. All participants underwent complete ophthalmic evaluations. Three drops of 0.5% tropicamide were used to obtain the cycloplegic refractive status of each participant. Questionnaires were used to acquire participant data from the 1995, 2005, 2010, and 2016 surveys. Prevalence of myopia (spherical equivalence of ≤−0.25 diopter [D]) and high myopia (≤−6.0 D) was assessed. Multivariate analyses of risk factors were conducted. The prevalence of myopia among all age groups increased steadily. From 1983 through 2017, the weighted prevalence increased from 5.37% (95% confidence interval [CI], 3.50%–7.23%) to 25.41% (95% CI, 21.27%–29.55%) for 7-year-olds (P = 0.001 for trend) and from 30.66% (95% CI, 26.89%–34.43%) to 76.67% (95% CI, 72.94%–80.40%) for 12-year-olds (P = 0.001 for trend). The prevalence of high myopia also increased from 1.39% (95% CI, 0.43%–2.35%) to 4.26% (95% CI, 3.35%–5.17%) for 12-year-olds (P = 0.008 for trend) and from 4.37% (95% CI, 2.91%–5.82%) to 15.36% (95% CI, 13.78%–16.94%) for 15-year-olds (P = 0.039 for trend). In both the 2005 and 2016 survey samples, children who spent less than 180 minutes daily on near-work activities showed significantly lower risks for myopia developing (<60 minutes: odds ratio [OR], 0.48 and 0.56; 60–180 minutes: OR, 0.69 and 0.67). In the 2016 survey, spending more than 60 minutes daily on electronic devices was associated significantly with both myopia and high myopia (OR, 2.43 and 2.31). The prevalence of myopia among schoolchildren increased rapidly from 1983 through 2017 in Taiwan. The major risk factors are older age and time spent on near-work activities. Use of electronic devices increased the amount of time spent on near-work and may increase the risk of developing myopia.