Comparison of spherical equivalent and estimated prevalence of myopia in school-age children between Shanghai and Yunnan in China.

Purpose: The purpose of this study was to compare spherical equivalent (SE) and estimated prevalence of myopia in school-age children between Shanghai and Yunnan in China, and to investigate the differences in SE and estimated prevalence of myopia between Han ethnicity and ethnic minorities in Yunnan.

Methods: This was a retrospective observational study, which enrolled one primary school and one junior high school in Shanghai, and two primary schools and two junior high schools in Yunnan in 2021. Refraction was measured using autorefractors without cycloplegia. Pearson correlation analysis, Chi-square test and multiple linear regression (MLR) were used for analysis.

Results: A total of 2,744 children in Shanghai and 1,769 children in Yunnan were examined, respectively. Less hyperopic SE was observed in Grades 1 and 2 in Shanghai compared to Yunnan (both P < 0.001). No significant difference in median SE between Han ethnicity and ethnic minorities in Yunnan was found in each grade (all P > 0.05). The estimated prevalence of myopia in Grades 1 (13.3% vs. 2.6%, P < 0.001) and 2 (16.1% vs. 7.6%, P = 0.003) were higher in Shanghai than in Yunnan, whereas the estimated prevalence of myopia of in Grade 7 (52.0% vs. 68.1%, P = 0.042) was lower in Han ethnicity than in ethnic minorities in Yunnan. MLR showed that the coefficient for age was -0.3351 (p < 0.001).

Conclusion: Spherical equivalent and estimated prevalence of myopia of school-age children in Yunnan are similar to Shanghai. Furthermore, a similar situation exists between Han ethnicity and ethnic minorities.