Prevalence, incidence and risk factors for myopia among urban and rural children in southern China: protocol for a school-based cohort study

IntroductionMyopia is the common cause of reduced uncorrected visual acuity among school-age children. It is more prevalent in urban than in rural areas. Although many myopia studies have focused on the effect of urbanization, it remains unclear how visual experience in urban regions could affect childhood myopia. This study aims to investigate the incidence and prevalence of myopia among school-age children in urban and rural settings, thereby identifying the environmental factors that affect the onset and progression of myopia. Methods and analysisA school-based cohort study will be conducted. We will enroll all first-grade students from an urban (10 primary schools) and a rural (10 primary schools) regions of Zhaoqing City, China. Over the 3-year follow-up period, students will receive detailed eye examinations annually and complete questionnaires about living habits and environment. In a 5% random subsample of the cohort, physical activity, light intensity, and eye-tracking data will be obtained using wearable devices. The primary outcome is incident myopia, defined as myopia detected during follow up among those without myopia at baseline. Ethics and DisseminationEthics approval was obtained from the ethics committee of the Zhongshan Ophthalmic Center (number: 2019KYPJ171). Study findings will be published in a peer-reviewed journal. Trial registration numberNCT04219228 ARTICLE SUMMARYO_ST_ABSStrengths and limitations of this studyC_ST_ABSO_LIThis is a longitudinal, school-based cohort study to assess the incidence and prevalence of myopia among school-age children in both urban and rural settings. C_LIO_LILarge sample size and the representative study population. C_LIO_LILight exposure and daily activities will be measured using wearable devices in a random subsample of the cohort. C_LIO_LIA myopia prediction model will be established using a deep learning algorithm based on the collected data. C_LI