目的：观察教育“双减”背景下上海市闵行区小学生的用眼行为对近视发生和发展的相关影响，评估用眼习惯和行为对儿童青少年近视发生的影响。

方法：采用分层整群抽样方法，选取研究对象后进行纵向研究观察。随机抽取教育“双减”政策落实后2021年9月至2021年12月上海市闵行区3 所小学的1-4年级学生进行为期2 a的观察，每年进行视力筛查获得裸眼视力、非睫状肌麻痹屈光数据和等效球镜度(SE)，进行眼轴生物测量获取眼轴(AL)、角膜曲率(CR)数据，同时采用调查问卷对研究对象的用眼行为进行调查。以近视度≤-0.50 D为诊断标准，统计近视发病率，以SE、AL变化评估近视进展情况，采用Logstic回归分析寻找近视的危险因素，分析用眼行为与近视发生发展的关系。

结果：本研究共有2 986名儿童完成2 a随访。基线时裸眼视力不良率为32.74%，随访1、2 a时分别为38.92%和43.73%，呈逐年增长趋势。在基线，1、2 a随访时，以裸眼视力结合非睫状肌麻痹性验光为临床筛查近视标准，近视发病率分别为24.72%、27.60%和29.64%，与以睫状肌麻痹验光后SE为近视诊断的标准(23.98%、27.03%和29.17%)比较均无差异(均P >0.05)。Logistic回归分析发现每日户外活动时长和每日睡眠时长是近视的保护因素(OR=0.54、0.84，均P<0.05)，而年龄、父母近视情况、每日线下教育、每日线上教育、每日电子产品使用和用眼姿势欠规范是近视的危险因素(OR=2.72、1.54、1.72、1.12、1.47、1.26，均P<0.001)。进一步分析基线近视儿童2 a内近视进展情况，结果显示基线年龄、父母近视情况、基线SE、每日线下教育时间、每日线上教育时间、每日使用电子产品时长、用眼姿势欠规范可能影响近视的快速发展。

结论：教育“双减”背景下上海闵行区小学生的用眼行为对近视发生发展具有重要影响。为了有效预防和控制近视，需要进一步加强用眼行为的教育和引导。

METHODS:A stratified cluster sampling method was adopted to select study subjects for longitudinal observation. Random sampling was conducted among grade 1-4 students from three primary schools in Minhang District, Shanghai from September to December 2021 after the implementation of the “double reduction” policy, with a 2-year observation period. Annual vision screenings were performed to obtain uncorrected visual acuity, non-cycloplegic refraction data, and spherical equivalent(SE). Biometric measurements were taken to acquire axial length(AL)and corneal curvature(CR). Questionnaires were administered to investigate the eye-use behaviors of participants. Taking myopia ≤-0.50 D as the diagnostic criterion, myopia incidence were calculated. SE and AL changes were used to evaluate myopia progression. Logistic regression analysis was employed to identify risk factors for myopia, and analyze the relationship between eye-use behaviors and myopia development or progression.

RESULTS:A total of 2 986 children complete a follow-up for 2 a. The baseline prevalence of poor vision was 32.74%, increasing to 38.92% and 43.73% at 1 and 2 a follow-up, respectively, demonstrating a yearly upward trend. Taking uncorrected visual acuity combined with non-cycloplegic refraction as clinical screening criteria for myopia, the incidence was 24.72%, 27.60%, and 29.64% at baseline, 1, and 2 a follow-ups, respectively. These showed no statistical significant difference compared to the diagnostic standard of cycloplegic refraction SE(23.98%, 27.03%, and 29.17%; all P>0.05). Logistic regression analysis found that daily outdoor and sleep duration were protective factors against myopia(OR=0.54, 0.84, all P<0.05), while age, parental myopia, duration of offline education, online education, electronic device usage, and poor visual posture were identified as risk factors(OR=2.72, 1.54, 1.72, 1.12, 1.47, 1.26, all P<0.001). Further analysis of myopia progression in baseline myopic children over 2 a revealed that age, parental myopia, baseline SE, duration of offline/online education, electronic device usage, and poor visual posture may contribute to rapid myopia progression.

CONCLUSION:Under the background of “double reduction”, the eye-use behavior among primary school students in Minhang District, Shanghai has an important impact on the occurrence and development of myopia. In order to effectively prevent and control myopia, it is necessary to further strengthen the education and guidance of eye-use behavior.