Systematic Review and Meta-Analysis on the Impact of COVID-19 Pandemic-Related Lifestyle on Myopia

2024 Chew Sek Jin Memorial Lecture: "Are we there yet?"

The journey from myopia being an intriguing scientific puzzle to part of clinical practice has been a long and varied path. Chew Sek Jin was one of the pioneers on this journey and, as director of the Singapore Eye Research Institute, initiated an ambitious research program that has helped us get to where we are today. His work was data-driven, embracing the power of epidemiological and longitudinal studies. He emphasized both the public health aspects and clinical management of myopia, pioneering the use of atropine in Singapore. With his work with Josh Wallman, he recognized the importance of research into the biological mechanisms of myopia.

Prevalence and Severity of Astigmatism in Children After COVID-19

Importance

Astigmatism can cause blurred vision at near and distance. It is common among schoolchildren and associated with ametropia. Although the COVID-19 pandemic generated a surge in myopia prevalence in children, the association with child astigmatism remains unknown.

Objective

To report the prevalence of refractive astigmatism and corneal astigmatism in schoolchildren from 2015 to 2023 and explore the associations between the pandemic and astigmatism.

Design, Setting, and Participants

This population-based cross-sectional study stratified all the primary schools registered with Education Bureau in Hong Kong into 7 clustered regions used by Hospital Authority Services in Hong Kong. Participants were schoolchildren aged 6 to 8 years who underwent comprehensive ocular examinations at 2 academic medical centers in Hong Kong from 2015 to 2023. Astigmatism was measured with optical biometry and auto-refractor after cycloplegia.

Exposure

COVID-19 pandemic.

Main Outcomes and Measures

The annual prevalence rates of refractive astigmatism and corneal astigmatism were the primary outcome measures. Logistic regression was used to evaluate the association of the pandemic with the risks of refractive astigmatism and corneal astigmatism. Linear regression was used to explore the association of the pandemic with the magnitudes of refractive astigmatism and corneal astigmatism.

Results

The cohort consisted of 21 655 children: 11 464 boys (52.9%) and 10 191 girls (47.1%); their mean (SD) age was 7.31 (0.90) years. The prevalence rate of refractive astigmatism of at least 1.0 diopter (D) was 21.4% and corneal astigmatism of at least 1.0 D 59.8% in 2015 and increased to 34.7% (difference, 13.3%; 95% CI, 9.3%-17.3%) and 64.7% (difference, 4.9%; 95% CI, 0.5%-9.2%), respectively, in 2022-2023. The pandemic was associated with a 20% increase in the risk of refractive astigmatism (odd ratio [OR], 1.20; 95% CI, 1.09-1.33; P < .001), 26% increase in the risk of corneal astigmatism (OR, 1.26; 95% CI, 1.15-1.38; P < .001), 0.04 D in the magnitude of refractive astigmatism (95% CI, 0.02-0.07; P < .001), and 0.05 D in the magnitude of corneal astigmatism (95% CI, 0.02-0.08; P < .001), compared with the prepandemic period of 2015-2019 and after adjusting for sociodemographic factors, parental astigmatism, and child myopia.

Conclusions and Relevance

This study found an increase in both the prevalence and severity of refractive astigmatism and corneal astigmatism after the COVID-19 pandemic. Corneal changes especially along the steepest meridian may explain some of the progression of corneal astigmatism. The potential impact of higher degrees of astigmatism may warrant dedicated efforts to elucidate the relationship between environmental and/or lifestyle factors, as well as the pathophysiology of astigmatism.

Myopia control efficacy of peripheral defocus soft contact lenses in children and adolescents: A meta-analysis

OBJECTIVES

To evaluate the effect of peripheral defocus soft contact lenses (PDSCLs) on controlling myopia progression in children and adolescents, and to compare it with orthokeratology (Ortho-K) and single vision lenses (SVLs).

METHODS

We conducted a systematic search of PubMed, the Cochrane Library, Medline, CNKI, CBM, VIP, and WanFang Data databases for randomized controlled trials (RCTs) and cohort studies that investigated the effects of PDSCLs on myopia control in children and adolescents. The published languages were limited to English and Chinese. The risk bias tool provided by the Cochrane risk-of-bias tool and Newcastle-Ottawa Scale were used to assess the risk bias of included studies of RCTs and CTs. The published biases of included studies were assessed by Egger`s test.

RESULTS

We included 21 studies, comprising 13 RCTs and 8 cohort studies, with a total of 1337 participants in the PDSCLs group, 428 in the Ortho-K group, and 707 in the SVLs group. The meta-analysis indicated no significant difference between PDSCLs and Ortho-K in controlling the increase of diopter (MD = 0.01, 95% CI: -0.06, 0.09; P = 0.69) and axial length (MD = -0.01, 95% CI: -0.02, 0.00; P = 0.28). Compared with SVLs, PDSCLs had a better effect in controlling the increase of diopter (MD = 0.23, 95% CI: 0.17, 0.28; P < 0.00001) and axial length (MD = -0.11, 95% CI: -0.12, -0.09; P < 0.00001) in children and adolescents.

CONCLUSIONS

Children and adolescents wearing PDSCLs can achieve better myopia control than those wearing SVLs, and their effect is comparable to that of Ortho-K.

Slowing of Greater Axial Length Elongation Stemming from the Coronavirus Disease 2019 Pandemic with Increasing Time Outdoors: The Tokyo Myopia Study

Purpose

To investigate the changes in axial length (AL) elongation and other ocular parameters before and during the coronavirus disease 2019 pandemic.

Design

A longitudinal school-based study.

Participants

Public elementary schoolchildren in Tokyo (grades 1-6; age, 6-12 years) participated in this study from 2018 to 2021.

Methods

All participants underwent eye examinations and provided written consent to measurements of the noncycloplegic refraction and ocular biometry including AL, among others. The students' parents also completed a questionnaire about the students' lifestyles. We included the right eye in our analysis and compared the changes in the ocular parameters among the periods using a linear mixed-effects model for repeated measures and examined the univariate and step-wise multiple regression analyses to evaluate the associations between myopia and other covariates.

Main Outcome Measures

Changes in AL elongation and other ocular parameters from 2018 to 2019 (prepandemic), that of 2019 to 2020 (immediately after the pandemic onset), and that of 2020 to 2021 (during the pandemic).

Results

A total of 578 students before the pandemic period, 432 immediately after the pandemic onset, and 457 during the pandemic period were evaluated. The changes in the ALs and spherical equivalents (SEs) a year before, immediately after onset, and during the pandemic were 0.31 mm/-0.20 diopter, 0.38 mm/-0.27 diopter, and 0.28 mm/-0.47 diopter, respectively (ALs, P < 0.001; SEs, P = 0.014). The results of the questionnaire showed that time spent outdoors daily had changed during the 3 years to 79, 63, and 77 minutes/day, respectively (P < 0.001). Time spent using smartphones or tablets increased year by year to 41, 52, and 62 minutes/day (P < 0.001). The greatest AL elongation occurred during the period when the shortest amount of time was spent outdoors during the 3 years.

Conclusions

These results suggested that the school closures and decreasing time spent outdoors might have caused greater AL elongation among schoolchildren in Tokyo; however, it is possible that, although the time spent in near work still increased, the return to the time spent outdoors to the prepandemic levels may have affected the slowing of AL elongation after lockdown.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Global estimates on the number of people blind or visually impaired by Uncorrected Refractive Error: a meta-analysis from 2000 to 2020

BACKGROUND

Uncorrected refractive error (URE) is a readily treatable cause of visual impairment (VI). This study provides updated estimates of global and regional vision loss due to URE, presenting temporal change for VISION 2020 METHODS: Data from population-based eye disease surveys from 1980-2018 were collected. Hierarchical models estimated prevalence (95% uncertainty intervals [UI]) of blindness (presenting visual acuity (VA) < 3/60) and moderate-to-severe vision impairment (MSVI; 3/60 ≤ presenting VA < 6/18) caused by URE, stratified by age, sex, region, and year. Near VI prevalence from uncorrected presbyopia was defined as presenting near VA < N6/N8 at 40 cm when best-corrected distance (VA ≥ 6/12).

RESULTS

In 2020, 3.7 million people (95%UI 3.10-4.29) were blind and 157 million (140-176) had MSVI due to URE, a 21.8% increase in blindness and 72.0% increase in MSVI since 2000. Age-standardised prevalence of URE blindness and MSVI decreased by 30.5% (30.7-30.3) and 2.4% (2.6-2.2) respectively during this time. In 2020, South Asia GBD super-region had the highest 50+ years age-standardised URE blindness (0.33% (0.26-0.40%)) and MSVI (10.3% (8.82-12.10%)) rates. The age-standardized ratio of women to men for URE blindness was 1.05:1.00 in 2020 and 1.03:1.00 in 2000. An estimated 419 million (295-562) people 50+ had near VI from uncorrected presbyopia, a +75.3% (74.6-76.0) increase from 2000 CONCLUSIONS: The number of cases of VI from URE substantively grew, even as age-standardised prevalence fell, since 2000, with a continued disproportionate burden by region and sex. Global population ageing will increase this burden, highlighting urgent need for novel approaches to refractive service delivery.

UCI EyeMobile Exam Findings from School Children Following on-Site Screening

Purpose

Uncorrected refractive errors (REs) and amblyopia can lead to visual impairment with deleterious effects on quality of life and academic performance. Early detection and treatment by community vision care programs, such as the UCI EyeMobile for Children, can aid in addressing preventable vision loss.

Methods

A total of 5074 children between the ages of 3 and 10 years were screened at 153 locations, including preschools, head start programs, and elementary schools within Orange County (OC), California (CA). Subsequently, 1024 children presented for comprehensive eye examinations. A retrospective analysis of all examined children was conducted, determining the frequency and severity of REs and amblyopia and the spectacle prescription rate by age. Propensity score matching analysis evaluated the effect of median household income on RE and amblyopia frequency.

Results

Among those who failed initial screening and were subsequently examined, significant rates of REs and amblyopia were detected: myopia (24.4%), hyperopia (35.4%), astigmatism (71.8%), anisometropia (8.9%), amblyopia (7.0%), and amblyopia risk (14.4%). A majority (65.0%) of those examined received prescription spectacles from UCI EyeMobile, with around a third requiring a new or updated prescription. The frequency of REs and amblyopia and the spectacle prescription rate were uniform across OC congressional districts. Myopia and amblyopia risk was positively and negatively associated with household income, respectively.

Conclusion

The UCI EyeMobile for Children serves as a vital vision care program, providing free vision screening, comprehensive eye examinations, and spectacles. A significant number of children required examination, and a high frequency of REs and amblyopia were detected in examined children, with subsequent provision of prescription spectacles to most children.

Immediate versus delayed sequential bilateral ICL implantation: A retrospective comparison of vault height and visual outcomes

PURPOSE

To compare the visual outcomes and risks of suboptimal vault-related complications between immediate sequential bilateral ICL surgery (ISBICLS) and delayed sequential bilateral ICL surgery (DSBICLS).

DESIGN

A retrospective cohort study.

METHODS

Patients who underwent bilateral ICL implantation between November 2014 and December 2021 at the Eye and ENT Hospital of Fudan University (Shanghai, China) were included and divided into two groups: (1) ISBICLS: both eye surgeries performed on the same day, and (2) DSBICLS: second eye surgery performed < 7 days following the first one. Propensity score matching (PSM) was performed to compare the visual outcomes. Multivariable logistic regression models were used to estimate the odds ratios (ORs) of the suboptimal vaults.

RESULTS

Finally, 10,985 eyes were included. After PSM, 204 first surgery eyes and 162 s surgery eyes with complete postoperative data were matched. The safety and efficacy indices did not statistically differ between groups (all > 1.00), except that ISBICLS first surgery eyes achieved better efficacy index than DSBICLS group (1.03 ± 0.26 vs. 1.08 ± 0.23, P = 0.034). Excessive vault was observed in eight (4.06 %) ISBICLS first eyes, one (0.50 %) DSBICLS first eye, and none in the second surgery eye in either group. An insufficient vault was observed in one second eye and one DSBICLS second eye. We found no evidence of differences in the rate of excessive vault (OR = 0.831, 95 % CI: 0.426-1.622, P = 0.588) or insufficient vault (OR = 0.609, 95 % CI:0.062-5.850, P = 0.668).

CONCLUSION

ISBICLS provided safety, efficacy, and refraction predictability comparable to DSBICLS without increasing the risk of suboptimal vault-related complications.

Impact of the coronavirus disease 2019 pandemic on the progression, prevalence, and incidence of myopia: A systematic review

We systematically reviewed the literature on the effects of the coronavirus disease 2019 (COVID-19) pandemic on the progression, prevalence, and incidence of myopia. A comprehensive literature search was performed on PubMed, Cochrane Central Register of Controlled Trials, and Scopus databases. Studies included in the review assessed myopia progression, prevalence, and/or incidence as the primary outcome. Of 523 articles yielded in the initial search, 23 studies (6 cross-sectional and 17 cohort) were eligible for inclusion. Sixteen of these were conducted in China and one each in Hong Kong, Turkey, Spain, Israel, India, Korea, and Tibet. Quality appraisals were conducted with the Joanna Briggs Institute Critical Appraisal Checklists. Of the included studies, a large majority reported a greater myopic shift and increase in myopia prevalence during the COVID-19 pandemic compared to the pre-COVID-19 years. All three studies on myopia incidence showed increased incidence during the COVID-19 pandemic. Myopia progression accelerated during the COVID-19 pandemic, even in individuals using low-concentration atropine eye drops in two studies but not in those using orthokeratology treatment in one study. Overall, the studies found that the COVID-19 pandemic and its associated home confinement measures generally increased myopia progression, prevalence, and incidence, even in individuals using low-concentration atropine eye drops.

Analysis and validation of potential ICD-related biomarkers in development of myopia using machine learning

PURPOSE

We aimed to identify and verify potential biomarkers in the development of myopia associated with immunogenic cell death (ICD).

METHODS

We download high myopia (HM) dataset GSE136701 from Gene Expression Omnibus. Differentially expressed genes in HM were identified to overlapped with ICD-related genes. Least absolute shrinkage and selection operator were used to select the Hub genes. Furthermore, the correlation between the hub genes and immune infiltration, immune response activities, and hub genes Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis was investigated using Spearman's rank correlation. Prediction of the miRNAs upstream of the Hub genes was based on the TargetScan database. We used guinea pig lens-induced myopia model's scleral tissues performed quantitative real-time polymerase chain reaction.

RESULTS

We identified overlapped with ICD-related genes (LY96, IL1A, IL33, and AGER) and two genes (LY96 and AGER) as hub genes. Single sample gene set enrichment analysis and Spearman's rank correlation revealed that hub gene expression levels in HM were significantly correlated with the infiltration percentages of CD56dim natural killer cells, macrophages, immature B cells, and the immune response activities of APC co-stimulation and Kyoto Encyclopedia of Genes and Genomes pathways, such as terpenoid backbone biosynthesis, aminoacyl-trna biosynthesis, Huntington's disease, oxidative phosphorylation; there were a few additional signaling pathways compared to normal samples. Additionally, several miRNA were predicted as upstream regulators of LY96 and AGER. LY96 was identified as a significantly differentially expressed biomarker in myopia guinea pig's scleral tissues, as verified by qPCR.

CONCLUSION

LY96 was identified and verified as a ICD-related potential myopia biomarker. Molecular mechanisms or pathways involved in myopia development by LY96 requires further research.

Eye exercises for myopia prevention and control: a comprehensive systematic review and meta-analysis of controlled trials

OBJECTIVES

To evaluate the efficacy of eye exercises in preventing and controlling myopia.

METHODS

We searched studies on eye exercises from nine Chinese and English databases from their inception to December 15, 2022. Using random-effect models and sensitivity/subgroup analyses, we estimated the effects of eye exercises compared to control on changes in three measures: visual acuity, refractive error (both quantified using standardized mean differences, SMDs), and protective/mitigating effects (assessed through risk ratios, RRs).

RESULTS

Eleven studies were included in the meta-analysis, with 921 participants. Nine studies had some concerns of bias in at least two domains, and two studies had a high risk of bias in two domains. Seven studies used visual acuity to measure myopia; visual acuity declined after eye-exercise interventions (SMD = -0.67, 95% CI -1.28 to -0.07, Z = 2.17, P = 0.03) and the effect was not better than control (SMD = -0.50, 95% CI -1.16 to 0.16, Z = 1.49, P = 0.14). Two studies used refractive error to measure myopia; the effect of eye-exercise interventions did not differ from control (SMD = -1.74, 95% CI -6.27 to 2.79, Z = 0.75, P = 0.45). Seven studies reported on protective/mitigating effects; eye exercises exhibited a greater protective/mitigating effect than control (RR = 0.40, 95% CI 0.23-0.71, Z = 3.13, P < 0.01).

CONCLUSIONS

Overall, the results suggest that eye exercises have limited to no efficacy in preventing or controlling myopia progression. Until robust evidence supports their efficacy, available evidence suggests retiring the eye-exercise policy.

Compensatory Interactions between Corneal and Internal Astigmatism despite Lifestyle Changes

This study explores whether children's refractive errors and visual behaviors reverted to pre-COVID-19 levels a year after normal schooling resumed in Hong Kong as well as the impact of corneal and internal astigmatism on refractive astigmatism development. Vision survey data and questionnaire results collected in 2022 (n = 119) and 2020 (n = 173) were compared. Cross-sectional data showed similar proportions of astigmatism (cylindrical power ≥ 0.75 D) in the 2020 (49.1%) and 2022 cohorts (55.5%). Despite a 0.28 D increase in corneal astigmatism, a compensatory 0.24 D increase in internal astigmatism of opposite direction kept refractive astigmatism relatively stable. The questionnaire data showed that children spent an additional 0.5 h/day outdoors on weekends post-resumption of normal schooling but engaged in more near-work activities, especially non-screen near-work, by approximately 1 h/day on both weekdays and weekends. These findings were supported by longitudinal data from 72 children who participated in both surveys. This study highlights the significant role of corneal and internal astigmatism in refractive astigmatism changes. Despite the return to in-person classes, children's total near-work time increased and astigmatism remained high. These findings underscore the need for comprehensive strategies to reduce the high environmental risks for refractive error development in children.

Management of COVID-19 in Ophthalmology

From its outbreak in early 2020, the new SARS-CoV-2 infection has deeply affected the entire eye care system for several reasons. Since the beginning of the COVID-19 pandemic, ophthalmologists were among the "high-risk category" for contracting the SARS-CoV-2 infection based on the notion that the eye was suspected to be a site of inoculation, infection, and transmission. Clinical ophthalmologists have been required to learn and promptly recognize the ocular manifestations associated with the COVID-19 disease, with its treatments and vaccinations. Restriction measures, lockdown periods, guidelines to prevent SARS-CoV-2 infection transmission, and the use of telemedicine and artificial intelligence modalities have induced profound modifications. These changes, which are most likely to be irreversible, influence routine clinical practice, education, and research, thus giving rise to a "new ophthalmology in the COVID era". This book chapter aims to provide several notions regarding COVID-19 in ophthalmology, including the SARS-CoV-2 virus infection and transmission modalities; the ocular manifestation associated with the COVID-19 disease; the drugs and vaccines used for COVID-19; the precautions adopted in the ophthalmic practice to limit the spread of the virus; the consequences of the pandemic on the ophthalmic patients, clinicians, and the entire eye care system; and, the future of ophthalmology in the era of "COVID new normal".

A large-scale analysis of refractive errors in students attending public primary schools in Mexico

A cross-sectional, retrospective study was conducted from September 2013 through July 2014 to determine the prevalence of refractive errors among students attending public primary schools in Mexico. Among 3,861,156 students at 14,566 public primary schools in all 32 states of Mexico, teachers identified reduced visual acuity in 1,253,589 (32.5%) using visual acuity measurement. Optometrists confirmed 391,498 [31.2%, mean (SD) age: 8.8 (1.9) years; 204,110 girls (52.9%)] had refractive errors using visual acuity measurement and noncycloplegic static retinoscopy. Among 288,537 (72.4%) of children with previous eyeglasses usage data reported, 241,505 (83.7%) had uncorrected refractive errors. Before prescription eyeglasses were provided, 281,891 students (72%) had logMAR visual acuity ≤ 0.2; eyeglasses corrected vision loss in 85.6% (n = 241,352) of them. Simple myopic astigmatism was the most frequent refractive error (25.7%, n = 100,545). Astigmatism > - 1.00 diopters was present in 54.6% of all students with ametropia. The anisometropia rate based on spherical equivalent difference between right and left eye ≥ 1.50 diopters was 3.9% (n = 15,402). Uncorrected refractive errors are an important issue in primary school students in Mexico. An updated study is needed to analyze the evolving trends over the past decade.

Prevalence of myopia among senior students in Fenghua, Eastern China, before and during the COVID-19 pandemic

Background

Myopia is a common cause of vision impairment worldwide. In China, the prevalence, the affected population, and the onset age of myopia are prominent issues. Prevention and intervention of myopia are great public health concerns.

Methods

This school-based retrospective study retrieved visual acuity and refractive data of senior students (grade 12th) from six high schools in Fenghua City, Zhejiang Province, eastern China, from 2016 and 2022. Noncycloplegic autorefraction was performed for refractive status. Students were divided into three subgroups by their school types. The overall myopia prevalence, as well as the prevalence of low myopia, moderate myopia, and high myopia, were calculated separately for each year. Statistical analyzes were performed using SPSS 25.0 and Graphpad Prism software.

Results

The mean myopia prevalence in Fenghua was 84.5% (95% CI: 84.0-85.0%), and a slightly downward trend was found in myopia prevalence after 2019, but the change was not statistically significant (p = 0.078). The overall prevalence of myopia was 79.6, 85.2, and 86.1% in vocational high schools, general high schools, and key high schools, respectively, with statistically significant differences (p < 0.001). The prevalence of myopia among senior students in the vocational high school was significantly lower than that in the other two high schools. There's no significant change in the overall prevalence of myopia (84.7% vs. 84.3%, p = 0.265) before and during the COVID-19 pandemic, and it remained statistically insignificant after stratifying by gender (male p = 0.207, female p = 0.918) or school types (vocational high school p = 0.112; general high school p = 0.299; key high school p = 0.393).

Conclusion

The prevalence of myopia among senior students in Fenghua is relatively high, and the COVID-19 pandemic has no significant impact on it. The prevalence of myopia among vocational high school students is lower than that of general high school and key high school. Attention should be paid to the effects of educational pressure on the prevalence of myopia among students.

Prevalence and Characteristics of Myopia in Adult Rhesus Macaques in Southwest China

Purpose

To investigate the prevalence of myopia in a large cohort of adult rhesus macaques at Yunnan Province in southwest China and describe the characteristics of myopic rhesus macaque eyes.

Methods

A total of 219 rhesus macaques 14.07 ± 2.72 years old (range, 8-21) were randomly recruited for this study. We performed fundus photography and measurements of cycloplegic refractive error (RE) and axial length (AL) on macaques.

Results

A total of 429 eyes of 219 macaques were examined. The median RE was -1.25 diopters (D), and the median AL was 18.69 mm. The prevalence of myopia was 62.47%, and one-third of the myopic eyes were highly myopic. The presence of fundus tessellations was higher in myopic eyes than non-myopic eyes (42.54% vs. 6.21%). The cutoff value for the presence of tessellations was -3.52 D for RE and 19.38 mm for AL. In myopic eyes, there were significant differences between grade 1 and grade 3 fundus tessellations on RE (-5.57 ± 2.97 D vs. -8.13 ± 3.51 D) and AL (19.66 ± 0.55 mm vs. 20.60 ± 1.06 mm). Beta-peripapillary atrophy (β-PPA) was found in 48.10% of myopic eyes and 6.83% of non-myopic eyes. The presence of β-PPA is associated with the presence of fundus tessellations, AL, and RE. The presence of β-PPA was higher in grade 3 than grade 1 fundus tessellations (94.4% vs. 76%).

Conclusions

More than half of adult rhesus macaques in southwest China are myopic, and one-third of the myopic ones are highly myopic. Similar to humans, tessellated fundi and β-PPA are the characteristic signs of myopic rhesus macaques. Adult rhesus macaques are optimal animal models for research on the pathogenesis of myopia.

Translational Relevance

This study not only provides a reference for the refractive state and AL in myopic rhesus macaques but also indicates that adult rhesus macaques with spontaneous myopia are optimal animal models for research on the pathogenesis of myopia.

Association between sleep duration and myopia among Chinese children during the COVID-19 pandemic: A cross-sectional study

Background

The studies on the association between sleep duration and myopia are limited, and the evidence is inconsistent. This study aimed to evaluate the association between sleep duration and myopia, cycloplegic spherical equivalent (SE) and axial length (AL) among Chinese children during the Corona Virus Disease 2019 (COVID-19) pandemic.

Methods

The study was a cross-sectional study on Chinese children aged 6-18 years. The comprehensive ophthalmic examinations for children included cycloplegic SE, AL, and standardized questionnaires. The questionnaire included sleep duration, parental myopia, outdoor time, and continuous near work duration without breaks. Myopia was defined as SE ≤-0.50 diopters (D).

Results

A total of 1,140 children were included in the analyses, with 84.7% of myopic children and 74.4% of children's daily sleep duration being more than 8 h/d. In univariate regression analysis, compared with sleep duration < 8 h/d, children with sleep duration of 8-9 and >9 h/d were less myopia (p < 0.01 for all), and had less myopic SE (p < 0.01 for all), and shorter AL (p < 0.01 for all). After adjusting for age, gender, parental myopia, outdoor time, and continuous near work duration without breaks, sleep duration was not associated with myopia, cycloplegic SE, and AL (p > 0.05 for all).

Conclusions

This study showed sleep duration was related to myopia, cycloplegic SE, and AL among Chinese children during the COVID-19 pandemic-related lifestyles, but no independent association.