AIM: To explore the characteristics of astigmatism in preschool children before, during and after the COVID-19 epidemic, so as to provide a reference for further prevention and control of children's vision.

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.