方法：横断面研究。采用随机分层整群抽样的调查方法，连续3a(2018～2020年)抽取成都市新都区4所小学的一年级到六年级学生(6～13岁)，每个年级3个班共10 153人，对纳入对象行视力检查及电脑验光，视力<5.0则进行散瞳验光，记录等效球镜度(SE)，并计算各年龄组近视患病率。采用卡方检验比较不同年度近视患病率的差异，单因素方差分析比较不同年度SE的差异。

结果：2018、2019、2020年近视患病率分别为35.98%、36.29%、42.52%(χ²=39.374，P<0.001)。6～9岁组学生2020年近视患病率明显提高(P<0.01)，分别为2019年的2.20倍(6岁)、2.08倍(7岁)、1.36倍(8岁)、1.24倍(9岁)。6～9岁组学生2020年SE出现明显近视化(P<0.05)，比2019年分别增长-0.34±0.76D(6岁)、-0.28±0.84D(7岁)、-0.29±1.41D(8岁)、-0.18±1.35D(9岁)。10～13岁组学生2018～2020年近视患病率及SE基本保持稳定(P>0.05)。

结论：新冠疫情居家隔离期后，6～9岁学生的近视进展明显加快，应更加重视6～9岁近视防控的窗口期。

METHODS:Cross-sectional study. A total of 10 153 primary school students from grade 1-6(age 6-13, three classes per grade)were selected from four primary schools in Xindu District of Chengdu for three consecutive years(2018-2020), by using a random stratified cluster sampling method. All students' visual acuity and spherical equivalent refraction(SE)were measured, a further cycloplegia optometry was conducted for those whose visual acuity was less than 5.0. The SE was recorded and the prevalence of myopia was calculated. Chi-square test was used to compare the difference of prevalence of myopia between different years. One-way Anova was used to compare the difference of SE among different years.

RESULTS: There was statistical difference in prevalence of myopia between the three years(2018: 35.98%, 2019: 36.29%, 2020: 42.52%; χ²=39.374, P<0.001). The prevalence of myopia among 6-9 years old students increased significantly in 2020(P<0.01). They were 2.20 times(6 years old), 2.08 times(7 years old), 1.36 times(8 years old)and 1.24 times(9 years old)of the previous year. Students aged 6-9 years showed an obvious myopic shift in SE in 2020(P<0.05). The increases were -0.34±0.76D(6 years old), -0.28±0.84D(7 years old), -0.29±1.41D(8 years old)and -0.18±1.35D(9 years old)than the previous year. The prevalence of myopia and SE remained stable among 10-13 years old students in 2018-2020(P>0.05).

CONCLUSION: After the COVID-19 home isolation period, there was a significant myopic shift among students aged 6-9 years old. We should pay more attention to the window period for myopia prevention and control of 6-9 years old.