目的：探讨新冠疫情前、中、后广州市白云区学龄前儿童散光变化特点，进一步为完善儿童视力防控提供参考。

方法：回顾性分析2018-01/2021-12连续4a参加广州市白云区儿童视力筛查的4岁以下学龄前儿童2 273例4 546眼的视力数据。根据入组年龄分为1岁年龄组(年龄<1岁，420例)、2岁年龄组(1岁≤年龄<2岁，543例)、3岁年龄组(2岁≤年龄<3岁，614例)、4岁年龄组(3岁≤年龄<4岁，696例)，分析纳入儿童双眼散光度数及散光患病情况。

结果：2018年，1岁年龄组双眼散光度数均高于其他年龄组(P<0.05)。2020年，四组学龄前儿童双眼散光度数相比2019年均明显增加(P<0.05)。2021年，四组学龄前儿童双眼散光度数相比2020年均明显下降(P<0.05)。2019～2020年，四组学龄前儿童右眼散光度数上升幅度均较左眼大(P<0.001)。2018～2021年，纳入学龄前儿童双眼散光患病率与散光度数变化趋势基本一致。

结论：广州市白云区学龄前儿童在1岁内散光度数最高、进展速度最快。新冠疫情前学龄前儿童散光度数及患病率相对稳定； 新冠疫情期间散光度数及患病率出现较大幅度上升，且右眼散光度数上升幅度较左眼大； 新冠疫情常态化防控后，散光度数及患病率明显下降。

METHODS: In the consecutive four years from January 2018 to December 2021, a retrospective analysis of vision data was conducted on 2 273 preschool children(4 546 eyes)younger than 4 years old who participated in children's vision screening test in Baiyun district, Guangzhou. They were divided into 1-year old group(ages<1-year old, 420 cases), 2-year old group(1-year ≤ ages <2-year, 543 cases), 3-year old group(2-year ≤ages <3-year, 614 cases), and 4-year old group(3-year ≤ ages<4-year, 696 cases)according to ages. The analysis included astigmatic degrees of children's eyes as well as their conditions of astigmatism.

RESULTS: In 2018, the astigmatic degrees of the both eyes of 1-year-old group were higher than those of other groups(P<0.05). The binocular astigmatic degrees of the preschool children in four groups were obviously higher in 2020 than 2019(P<0.05), while they were significantly decreased in 2021 when compared with 2020(P<0.05). From 2019 to 2020, the increase of astigmatic degrees of the right eye is more considerable than the left eye of preschool children in those four groups(P<0.001). Furthermore, the morbidity of astigmatism basically echoes with the changing tendency of astigmatic degrees from 2018 to 2021.

CONCLUSIONS: Preschool children in Baiyun district, Guangzhou, have the highest degree of astigmatism and the fastest progression rate within 1 year old. Before COVID-19 epidemic, the changes in astigmatism and prevalence were relatively stable; during COVID-19 epidemic, the astigmatism and prevalence increased significantly and the astigmatic degrees of right eye increased more than that of the left eye; after the normalization of epidemic prevention and control, the astigmatism and prevalence decreased significantly.