The first case of coronavirus disease 2019 (COVID-19) in United States was identified in January 2020,
1 and by early March, the first case in Houston, Texas, was diagnosed. Soon after, officials issued a stay-at-home order to slow the spread of the virus and reduce pressure on the health care system. Secondary to quarantine and lockdown measures, children's lifestyles dramatically changed. All schools closed for in-person learning, and children shifted to electronic devices for virtual education, social interactions, and entertainment. These stay-at-home orders likely resulted in significant changes in the amount of time that children spent outdoors, engaged in near work, and used screens. Near work and time outdoors are both considered factors that can affect eye growth and myopia, or nearsightedness, in children.
2–8
Myopia is the result of a mismatch between optical power of the eye and its length. It is the most common type of refractive error and is considered a major cause of preventable visual impairment in the world.
9,10 Currently, 22.9% of the world population (1.4 billion) is myopic, and its prevalence is expected to increase to 4.8 billion by 2050.
11 Myopia represents a significant socioeconomic burden globally
12 and, if left uncorrected, can affect school performance of children and quality of life.
13 While the exact etiology is still unknown, myopia is thought to be the result of complex interactions between genetic, environmental, and behavioral factors.
14–19 There is an abundance of literature suggesting an association between time spent outdoors and light exposure with the development and progression of myopia in children.
2–5,20 According to these studies, less outdoor time and lower light exposure are correlated with increased myopia prevalence and, in some reports, also with myopia progression.
5,20 However, evidence concerning the role of near work in myopia onset and progression is conflicting. Many authors report that increased near work is associated with higher incidence of myopia in school-age children,
6–8 while others did not observe such a relationship.
21–24 In addition, the contributions of screen time in myopia are not well understood. A recent review reported mixed findings with respect to an influence of screen time on myopia.
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The goal of this study was to assess subjective and objective measures of physical activity, outdoor time, near work, electronic device use, and sleep during summer 2020, while COVID-19–related quarantine measures were in place, in myopic and non-myopic children, in the Houston area. Behaviors were compared with a typical summer and school session prior to the COVID-19 pandemic using a questionnaire.