Design, methodology, and baseline of whole city-million scale children and adolescents myopia survey (CAMS) in Wenzhou, China

Abstract

Background: Myopia is the most common visual impairment in children and adolescents worldwide. This study described an economical and effective population-based screening pipeline and performed the project of a million scale children and adolescents myopia survey (CAMS), which will shed light on the further study of myopia from the level of epidemiology and precision medicine.

Methods: We developed a novel population-based screening pattern, an intelligent screening process and internet-based information transmission and analysis system to carry out the survey consisting of school children in Wenzhou, China. The examination items include unaided distance visual acuity, presenting distance visual acuity, and non-cycloplegic autorefraction. Myopia and high myopia were defined as spherical equivalent (SE) ≤ - 1.00 diopters (D) and SE ≤ - 6.00 D, respectively. Next, the reports of the vision checking were automatically sent to parents and the related departments. The CAMS project will be done two to four times annually with the support of the government. An online eyesight status information management system (OESIMS) was developed to construct comprehensive and efficient electronic vision health records (EVHRs) for myopia information inquiry, risk pre-warning, and further study.

Results: The CAMS completed the first-round of screening within 30 days for 99.41% of Wenzhou students from districts and counties, in June 2019. A total of 1,060,925 participants were eligible for CAMS and 1,054,251 (99.37% participation rate) were selected through data quality control, which comprised 1305 schools, and 580,609, 251,050 and 170,967 elementary, middle, and high school students. The mean age of participants was 12.21 ± 3.32 years (6-20 years), the female-to-male ratio was 0.82. The prevalence of myopia in elementary, middle, and high school students was 38.16%, 77.52%, and 84.00%, respectively, and the high myopia incidence was 0.95%, 6.90%, and 12.98%.

Conclusions: The CAMS standardized myopia screening model involves automating large-scale information collection, data transmission, data analysis and early warning, thereby supporting myopia prevention and control. The entire survey reduced 90% of staff, cost, and time consumption compared with previous surveys. This will provide new insights for decision support for public health intervention.

Keywords: Baseline; Myopia prevention and control; Population-based; Vision screening.

Fig. 1

Flowchart of the CAMS. a Location of the CAMS and regional population percentage of Wenzhou. b Framework of the CAMS. c Quality control, showing the participants available for analysis in the baseline

Fig. 2

Myopia prevalence of different regions in Wenzhou. a A total of eleven counties, districts, and cities. b Myopia prevalence. c High myopia prevalence

Fig. 3

Spherical equivalent (SE) distribution and myopia prevalence for children and adolescents. a SE distribution for school students aged 6 to 20 years. b Myopia prevalence for school students aged 6 to 20 years. c SE distribution for school students with different grades. d Myopia prevalence for school students of different grades

Fig. 4

Prevalence of myopia and high myopia in different school levels and school types. a & b According to school level, elementary, middle, and high schools were divided into provincial first level, provincial second level, ordinary, municipal first level and municipal second level. c & d According to school type, elementary, middle, and high schools were divided into art school, general school, vocational school, sport school and martial school. Pearson chi-squared test was performed to determine significance between each pair of condition. P-value: **P < 0.01, ***P < 0.001, ****P < 0.0001