Abstract
OBJECTIVE: To describe the prevalence of myopia and pre-myopia among preschool children aged 5-6 years in ten provinces or municipalities (hereinafter referred to as province) of China, and to provide a reference for the prevention and control of myopia, and the allocation of related health resources. METHODS: Convenience sampling was used to select preschool children aged 5-6 years from 21 cities in 10 provinces (including 8 provinces and 2 municipalities) in China. Cycloplegic autorefraction was conducted. The distribution of myopia and pre-myopia was described using frequencies and percentages. The Chi-square test was used to compare the differences in the prevalence of myopia and pre-myopia between regions with different varying economic development levels and between boys and girls, with a significance level of α=0.05. RESULTS: A total of 12 926 preschool children aged 5-6 years were surveyed. The myopia prevalence was 5.5%, and the overall prevalence of myopia and pre-myopia was 43.4%. Boys had higher rates of myopia and overall prevalence of myopia and pre-myopia than girls (5.7% vs. 5.2%, 46.4% vs. 40.1%), though the difference in myopia prevalence was not statistically significant. Stratified analysis by the province, there was no statistically significant differences in the prevalence of myopia between boys and girls in any province (P>0.05), but in 8 provinces, the prevalence of myopia in boys was slightly higher than in girls. The overall prevalence of myopia and pre-myopia in boys was higher than in girls across all the 10 provinces, with 5 provinces showing statistically significant differences (P < 0.05). The investigated areas were divided into two categories, relatively more-developed areas and relatively less-developed areas, based on per capita gross domestic product (GDP). In 6 provinces, there was no statistically significant difference in the prevalence of myopia between the two categories of areas. In 2 provinces, the prevalence was higher in relatively more-developed areas, and in 2 provinces, it was higher in relatively less-developed areas. In 4 provinces, there was no statistically significant difference in the overall prevalence of myopia and pre-myopia between the two categories of areas with relatively more-developed and relatively less-developed areas. In 3 provinces, the prevalence was higher in relatively more-developed areas, and in 3 provinces, it was higher in relatively less-developed areas. CONCLUSION: The prevalence of myopia and pre-myopia among preschool children aged 5-6 years is relatively high. Boys show higher overall prevalence of myopia and pre-myopia than girls, but there is no significant difference in the prevalence of myopia. There is no consistent association between the level of economic development and the incidence of myopia and pre-myopia in each province.