To explore the progression of myopia among primary school students in Zhengzhou city and its influencing factors.

Using a random stratified cluster sampling method, a total of 3167 primary school students (6334 eyes) from grades 1 to 4 in Navigation School, Experimental Primary School, and Sicun Road Primary School in Zhengzhou City from March 2021 to April 2021 were selected. Among them, there are 1674 male students (3348 eyes) and 1493 female students (2986 eyes) with an average of (8.7±1.2) years old (ranged from 6 to 14 years old). By April 2023, these students have be followed up for 2 years and collected data twice. In 2023, 2748 individuals (5496 eyes) were effectively followed up, with 1452 males (2904 eyes) and 1296 females (2592 eyes) with an average of (10.6±1.1) years old (ranged from 8 to 16 years old). According to the spherical equivalent (SE), vision was divided into myopia and non-myopia, and myopia was further divided into mild, moderate, and high myopia. The incidence of myopia in different genders and grades was expressed in terms of frequency and percentage, and compared by chi square test for inter group. The annual progress of SE followed a normal distribution, was expressed as ±s, and compared by one-way ANOVA between different grades within the same gender, and independent sample t-test between different genders within the same grade. The logistic regression model was used to analyze the risk of myopia among non-myopic students with different levels of SE.

The overall prevalence of myopia among primary school students in grades 1 to 4 in Zhengzhou City in 2021 was 51.88% during the baseline period, and 67.03% after 2 years, with a statistically significant difference (χ²= 186.29, P<0.05). The incidence rates of myopia in grades 1 to 4 during the baseline period in 2021 were 33.26%, 51.79%, 59.28%, and 70.13%, respectively. After followup for 2 years, the incidence rates were 54.84%, 68.34%, 71.61%, and 84.16%, respectively, with statistically significant differences (χ²= 85.33, 46.50, 24.29, 25.46; P<0.05), and the incidence of myopia gradually increased with grade, with a statistically significant difference (χ_trend²=228.58, 118.05; P_trend<0.05). The average annual incidence rate of myopia among primary school students in grades 1 to 4 from 2021 to 2023 was 23.26%. The average annual incidence rate of myopia among pupils in grades 1 to 4 were 22.34%, 25.26%, 21.48% and 25.96%, respectively. There was no significant difference in the average annual incidence rate among different grades (χ²= 5.91, P>0.05). Logistic regression model analysis showed that, with SE ≥+ 0.50 D as a reference, the risk of developing myopia at the 0 D ≤ SE <+ 0.50 D level was 3.21 (2.206, 4.674) times higher in males, and the risk of developing myopia at the -0.50 D < SE <0 D level was 7.226 (4.641, 11.253) times higher. Among girls, the risk of developing myopia at 0 D ≤ SE <+ 0.50 D level increased by 4.554 (2.967, 6.991) times, and the risk of developing myopia at -0.50 D ≤ SE ≤0 D level increased by 4.554 (2.967, 6.991) times.

From 2021 to 2023, the incidence rate of myopia among primary school students in grades 1 to 4 in Zhengzhou is high, and the prevalence rate is growing rapidly. At present, more attention should be paid to the prevention and control of myopia in children and adolescents, with a focus on the female population and children and adolescents with insufficient foresight reserves.