Increased myopia during the COVID-19 pandemic

Paper title: Progression of Myopia in School-Aged Children After COVID-19 Home Confinement

Authors: Jiaxing Wang (1), Ying Li (1), David Musch (2), Nan Wei (3), Xiaoli Qi (3), Gang Ding (3), Xue Li (3), Jing Li (3), Linlin Song (3), Ying Zhang (3), Yuxian Ning (3), Xiaoyu Zeng (3), Ning Hua (3), Shuo Li (4), Xuehan Qian (3)

1. Department of Ophthalmology, Emory University, Atlanta, Georgia
2. Department of Ophthalmology and Visual Science, Department of Epidemiology, University of Michigan, Ann Arbor
3. Department of Strabismus and Paediatric Ophthalmology, Tianjin Medical University Eye Hospital, Tianjin, China
4. Department of Respiratory and Critical Medicine, Tianjin Medical University General Hospital, Tianjin, China

Date: 2021

Reference: Wang J, Li Y, Musch DC, Wei N, Qi X, Ding G, Li X, Li J, Song L, Zhang Y, Ning Y, Zeng X, Hua N, Li S, Qian X. Progression of Myopia in School-Aged Children After COVID-19 Home Confinement. JAMA Ophthalmol. 2021 Mar 1;139(3):293-300. [link]

The authors of this study assessed refractive changes and prevalence of myopia in schools annually over a 5-year period between 2015 and 2020.

Schoolchildren were confined to home during the COVID-19 pandemic between January and June 2020, and vision screening resumed when the schools reopened.

A significant increase in both myopia prevalence and myopic refractive error was seen for younger children aged between 6 and 8 years old.  Between 2015 and 2019, the prevalence for 6, 7 and 8yr olds was 5.7%, 16.2% and 27.7% respectively.  In 2020, this increased to 21.5%, 26.2% and 37.2%, respectively. 

In the 4 years prior to the pandemic confinement period, the increase in myopia had been relatively constant with an increase of between -0.06D and -0.11D for 6 to 8yr olds.  When screening resumed, a larger myopic shift of -0.30D was found for this age group over a period of only 6 months.

Myopia progression was found to decrease with age for older children aged 9-13yrs (between -0.14D and -0.05D/year, being lower with older age).  Older children spent longer online each day for school learning than the younger cohort (2.5 hours daily for school grades 3 to 6, compared to 1 hour for grades 1 and 2).  However, the older children did not show the same increase in myopia prevalence or progression.

Being confined to home during the COVID-19 pandemic was associated with significantly increased myopia in younger rather than older children, suggesting there is a critical period of higher susceptibility to changes in lifestyle.

Children aged 8 years and younger may be more vulnerable to changes in their lifestyle than older children, even if the changes are short-term, meaning this a key stage to ensure they have limited screen time indoors and maximized outdoor time.

There is still much to learn regarding the optimum ratio of outdoor to indoor study or screen times, to avoid myopia progression whilst achieving a lifestyle balance, and how much this may vary for different age groups where the plasticity of myopia decreases with a child's age.

Follow-up studies on the children affected by the COVID-19 pandemic will tell us the extent home confinement has had on myopic prevalence and progression in children.

Title: Progression of Myopia in School-Aged Children After COVID-19 Home Confinement

Authors: Jiaxing Wang, Ying Li, David Musch, Nan Wei, Xiaoli Qi, Gang Ding, Xue Li, Jing Li, Linlin Song, Ying Zhang, Yuxian Ning, Xiaoyu Zeng, Ning Hua, Shuo Li, Xuehan Qian

Purpose: To investigate the refractive changes and prevalence of myopia in school-aged children during the COVID-19 home confinement. 

Methods: A prospective cross-sectional study using school-based photoscreenings in 123 535 children aged 6 to 13 years from 10 elementary schools in Feicheng, China, was conducted. The study was performed during 6 consecutive years (2015-2020). Data were analyzed in July 2020. Noncycloplegic photorefraction was examined using a photoscreener device. The spherical equivalent refraction was recorded for each child and the prevalence of myopia for each age group during each year was calculated. The mean spherical equivalent refraction and prevalence of myopia were compared between 2020 (after home confinement) and the previous 5 years for each age group.

Results: Of the 123 535 children included in the study, 64 335 (52.1%) were boys. A total of 194 904 test results (389 808 eyes) were included in the analysis. A substantial myopic shift (approximately -0.3 diopters [D]) was found in the 2020 school-based photoscreenings compared with previous years (2015-2019) for younger children aged 6 (-0.32 D), 7 (-0.28 D), and 8 (-0.29 D) years. The prevalence of myopia in the 2020 photoscreenings was higher than the highest prevalence of myopia within 2015-2019 for children aged 6 (21.5% vs 5.7%), 7 (26.2% vs 16.2%), and 8 (37.2% vs 27.7%) years. The differences in spherical equivalent refraction and the prevalence of myopia between 2020 and previous years were minimal in children aged 9 to 13 years.

Conclusions: Home confinement during the COVID-19 pandemic appeared to be associated with a significant myopic shift for children aged 6 to 8 years according to 2020 school-based photoscreenings. However, numerous limitations warrant caution in the interpretation of these associations, including use of noncycloplegic refractions and lack of orthokeratology history or ocular biometry data. Younger children's refractive status may be more sensitive to environmental changes than older ages, given the younger children are in a critical period for the development of myopia.