COVID-19 lockdowns increased risk of progression, incidence of myopia in children
Quarantines imposed during the COVID-19 pandemic were a risk factor for the progression and incidence of myopia in school-age children in China, according to a study published in Ophthalmology.
“As a result of coronavirus disease 2019 (COVID-19) causing an unprecedented global pandemic, most nations have imposed various strict containment measures on citizens, including limited outdoor activities and school closures, to prevent spread of the virus that causes COVID-19,” Liangde Xu, PhD, associate professor of ophthalmology and optometry at Wenzhou Medical University, and colleagues wrote. “These COVID-19 quarantines have led to billions of students simultaneously experiencing life-altering challenges, which may influence the incidence or worsening of myopia, or both, among schoolchildren. Establishing a COVID-19 intervention model in a clinical study is highly valuable for uncovering the crucial risk factors of myopia development.”
Xu and colleagues included 1,001,749 students, aged 7 to 18 years, from 11 school districts in a large-scale intervention study to assess the impact of COVID-19 lockdowns on myopia progression and incidence. Participants were classified into two groups, grade stage I (grades 1-6) and grade stage II (grades 7-12) and were instructed to complete self-administered questionnaires. Investigators measured visual acuity and spherical equivalent refraction (SER) at baseline and at a 12-month follow-up.
Myopia was defined as an uncorrected visual acuity of less than 20/25 and an SER of -0.50 D or less, and high myopia was defined as an SER of -6.00 D or less.
Researchers found that from June 2019 to June 2020 overall myopia prevalence increased from 52.89% to 59.35%, with high myopia increasing from 4.11% to 4.99%. The 6-month myopia progression among all schoolchildren also increased from -0.23 D before quarantine to -0.343 D after quarantine (P < .001), and the half-year incidence rate of myopia increased from 8.5% to 13.62% (P < .001).
A mean increase in myopia prevalence of 8.54% in grade stage I was observed compared with 4.32% in grade stage II, with the prevalence of high myopia increasing from a mean of 4.46% during grade 7 to a mean of 13.25% during grade 12.
Researchers also found that increased time online was significantly and positively linked with increased myopia incidence and progression, while increased outdoor activity time was significantly and negatively linked with increased myopia incidence and progression.
“The present study provides valuable intervention data to assess the impact of COVID-19 quarantine-related lifestyle changes on myopia development among schoolchildren,” Xu and colleagues concluded. “We found an interesting COVID-19 induced influence of myopia developing among children and adolescents, indicating that different intervention strategies should be applied to control myopia among elementary and high school students.”
Perspective
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The World Health Organization reports that the prevalence of myopia is increasing at an alarming rate; 1.89 billion people in the world have myopia. It is predicted that 50% of the people in the world will have myopia by the year 2050. This will be an increase to 5 billion people. It is predicted that uncorrected myopia will increase the prevalence of blindness, and that the risk of retinal detachments, glaucoma and age-related macular degeneration will increase. With an increase in myopia worldwide, it is pertinent to researchers to study habits that increase myopia prevalence.
This report is about a study of changes in activity of subjects due to the COVID-19 pandemic. The researchers studied whether increased use of digital devices and reduced time spent outdoors was a link to myopia progression. The authors are discussing two behavioral changes that have caused worsening of myopia in school-age children. The report was completed on a large scale (over 1 million students) but is limited to only Chinese children. The results indicate an approximately 6.46% increase in myopia during the duration of COVID-19 quarantine. The results can be alarming for practitioners due to the increased digital screen time.
An increase in myopia could lead to many not having access to services for prescriptions, thereby increasing amblyopia. The global cost of reduced productivity due to uncorrected myopia was $244 billion in 2015. Predictions are that this will more than double by the year 2050. Further studies should evaluate functional imbalances in accommodation and fusion as potential causes for developing myopia, effect on development, effect on socialization and impact on learning.
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