BackgroundHigh prevalence SERO
of myopia MESHD myopia HP
of adolescent has been a global public health concern. Their risk factors and effective prevention methods for myopia HP myopia MESHD
across schoolchildren developmental stages are critically needed but remain uncertain due to the difficulty in implementing intervention measurements under normal life situation. We aimed to study the impact of the COVID-19 MESHD
quarantine on myopia HP myopia MESHD
development among over one-million schoolchildren.
MethodsWe designed the ongoing longitudinal project of Myopic Epidemiology and Intervention Study (MEIS) to biannually examine myopia HP
among millions of schoolchildren for ten years in Wenzhou City, Zhejiang Province, China. In the present study, we performed three examinations of myopia HP
in 1,305 elementary and high schools for schoolchildren in June 2019, December 2019 and June 2020. We used the normal period (June-December 2019) and COVID-19 MESHD
quarantine period (January-June 2020) for comparisons. Myopia HP
was defined as an uncorrected visual acuity of 20/25 or less and a spherical equivalent refraction (SER) of -0.5 diopters (D) or less. High myopia HP
was defined as an SER of -6.0 D or less.
FindingsIn June 2019, 1,001,749 students aged TRANS
7-18 were eligible for examinations. In the 6-month and 12-month follow-up studies, there were 813,755 eligible students (81.2%) and 768,492 eligible students (76.7%), respectively. Among all students, we found that half-year myopia HP
progression increased approximate 1.5 times from -0.263 D (95% CI, -0.262 to -0.264) during normal period to -0.39 D (95% CI, -0.389 to -0.391) during COVID-19 MESHD
quarantine (P < 0.001). Multivariate Cox regression analysis identified grade rather than age TRANS
was significantly associated with myopia HP
(Hazard ratio [HR]: 1.10, 95% CI, 1.08 to 1.13; P < 0.001) and high myopia HP
(HR: 1.40, 95% CI, 1.35 to 1.46; P < 0.001) after adjustment for other factors. The prevalence SERO
, progression, and incidence of myopia and high HP myopia HP
could be categorized into two grade groups: I (grades 1-6) and II (grades 7-12). Specifically, COVID-19 MESHD
quarantine for 6 months sufficiently increased risk of developing myopia HP
(OR: 1.36, 95% CI, 1.33 to 1.40) or high myopia HP
(OR: 1.30, 95% CI, 1.22 to 1.39) in Grade Group I, but decreased risk of developing myopia HP
(OR: 0.45, 95% CI, 0.43 to 0.48) or high myopia HP
(OR: 0.57, 95% CI, 0.54 to 0.59) in Grade Group II.
InterpretationThe finding that behavioral modifications for six months during COVID-19 MESHD
quarantine sufficiently and grade-specifically modify myopia HP
development offers the largest human behavioral intervention data at the one million scale to identify the grade-specific causal factors and effective prevention methods for guiding the formulation of myopia HP
prevention and control policies.
FundingKey Program of National Natural Science Foundation of China; the National Natural Science Foundation of China; Scientific Research Foundation for Talents of Wenzhou Medical University; Key Research and Development Program of Zhejiang Province.
Research in contextO_ST_ABSEvidence before this studyC_ST_ABSMyopia is the most-common refractive error worldwide. Myopia HP
with younger onset may result in developing high myopia HP
, which is associated with sight-threatening ocular diseases such as maculopathy, retinal detachment HP
, opticneuropathy, glaucoma HP
, retinal atrophy HP
, choroidal neovascularization HP
. In light of the increasing prevalence SERO
of myopia and high HP myopia HP
has been a global public health concern, the impact of COVID-19 MESHD
lockdown on myopia HP
development has gained substantial attention. We searched PubMed, Google Scholar, and MEDLINE databases for original articles reported between database inception and November 10, 2020, using the following search terms: (coronavirus OR COVID* OR SARS-COV-2 OR lockdown OR quarantine) AND ( myopia HP
OR short-sightedness OR refractive error). To date, there was no original study reported to uncover the influence of COVID-19 MESHD
quarantine on myopia HP
Added value of this studyThis study provides the largest longitudinal intervention data on myopia HP
progression in Chinese schoolchildren covering all grades of schoolchildren at one-million scale. COVID-19 MESHD
quarantine model uncovers that behavioral modifications for six months may lead to significant increase of overall prevalence SERO
of myopia HP
associated with their increased screen times and decreased outdoor activity times. Importantly, their effects on developing myopia or high HP myopia HP
of students are grade-dependent, which were risk factors for elementary schools period but protective factors for high schools period partly due to reduced school education burden.
Implications of all the available evidenceThis one-million schoolchildren myopia HP
survey offers evidence that six months behavioral modifications sufficiently and grade-specifically change the progression of myopia and high HP myopia HP
. In view of the increased use of electronic devices is an unavoidable trend, effective myopia HP
prevention strategy according to grade among students is urgently needed. Since COVID-19 MESHD
outbreak is still ongoing and spreading, international collaborate efforts are warranted to uncover the influence of COVID-19 MESHD
on myopia HP
progression to further substantiate these findings.