Reduced vision, refractive errors and health-related quality of life among adolescents in rural China

Global prevalence of myopia in children using digital devices: a systematic review and meta-analysis

BACKGROUND

The global prevalence of myopia among children has considerably increased over the past few decades, affecting the children's eye health and quality of life. According to the inconsistent reports of myopia among children, the purpose of this systematic review and meta-analysis study was to determine the global prevalence of myopia in children using digital devices.

METHODS

Various databases (PubMed, ScienceDirect, Embase, Web of Science, Scopus, and Google Scholar) were searched systematically (No time limit until September 2023, last updated in May 2024) using keywords of "Myopia Prevalence", "Children", "TV", "Computer", "Video games", and "Smartphone". PRISMA guideline was also used for paper collection based on the Inclusion/Exclusion criteria. The quality of articles was determined based on the STROBE checklist. Data analysis, heterogeneity assessment, publication bias, and all factors influencing heterogeneity were executed using the CMA software (v.2).

RESULTS

Initially, 828 articles were identified through database assessment. 563 and 133 papers were evaluated using primary and secondary assessments, respectively. Ultimately, 17 eligible articles were selected for meta-analysis following paper exclusion. In this era, the global prevalence of myopia among children using computer and video games was reported 28.8% (95%CI:21.1-38), using TV (TV watching) was 35.4% (95%CI:20.6-53.7), and smartphone usage was 31.4% (95%CI:13.5-57.3).

CONCLUSION

Myopia is now recognized as a critical global issue with a daily increasing rate. Technology, along with various digital devices, causes several issues in this era. It is suggested that the application of all digital screens and smart devices can potentially increase the risk of myopia among children. Thus, the reduction of these smart device applications in children can alleviate the potential risk of myopia. The results of this study can be a guide for health policymakers and a useful advertisement for society and families in paying attention to this problem in children, as well as increasing health interventions such as early screening and timely diagnosis for treatment. In this regard, it can be effective in both prevention and increasing the quality of life of children.

Effects of Insufficient Sleep on Myopia in Children: A Systematic Review and Meta-Analysis

Myopia is increasingly prevalent in children. Its association with insufficient sleep has been studied, yielding inconsistent findings. This review aims to assess the association of insufficient sleep with myopia and myopia-related refractive parameters in children. A total of 657 articles were identified, of which 40 were included in the systematic review and 33 were included in the meta-analysis. Results showed that insufficient sleep was significantly associated with an increased prevalence of myopia (odds ratio [OR] = 1.59; 95% confidence interval [CI] = 1.31, 1.95; I 2 = 99%), and an increased prevalence of high myopia (OR = 3.36; 95% CI = 1.26, 9.00; I 2 = 96%). Shorter sleep duration was significantly linked to faster changes in axial length (AL) (β = 0.05; 95% CI = 0.02, 0.08; I 2 = 0%). However, correlation between insufficient sleep and the incidence of myopia, spherical equivalent refraction, corneal curvature radius (CR) and AL/CR were insignificant. Moreover, the effect of insufficient sleep on premyopia and astigmatism was not well-studied. The results of this study suggest that insufficient sleep may be an important risk factor for the development of myopia in school-aged children. Therefore, in addition to ensuring sufficient outdoor activities and reducing near work, it is necessary to inform children and parents about the importance of adequate sleep to mitigate the risk of myopia.

Gender Difference of the Association Between Sleep Duration and Myopia Among Children and Adolescents

Purpose

With girls typically exhibiting higher rates of myopia than boys, however, the mechanisms behind this gender difference remain unclear. This study aims to investigate the gender disparities in the relationship between myopia, sleep duration, physical activity, and BMI.

Patients and Methods

A total of 3138 primary and secondary school students were included. Mplus 8.3 was used to perform the multiple mediation analysis.

Results

Sleep duration was indicated to directly affect myopia (β=0.273, 95% CI=0.184-0.356) and through physical activity, BMI, physical activity and BMI three significantly mediation pathways, respectively. In terms of gender, the mediating direct effect of sleep duration on myopia of boys was 66.96%, which is much higher than that of girls' 50.91%. And the mediating indirect effect of sleep duration on myopia through physical activity and BMI are 32.65% and 12.10% respectively among girls, both of which are significantly higher than that of boys.

Conclusion

The study found that there are significant differences in the impact of sleep duration on myopia in children and adolescents of different genders. In this regard, while paying attention to the sleep duration of children and adolescents, special attention should also be paid to the indirect impact of girls' physical activity and BMI on myopia, and targeted measures should be formulated according to children of different genders to effectively protect the eye health of children and adolescents.

Quality of life, functioning and participation of children and adolescents with visual impairment: A scoping review

BACKGROUND

Vision has a key role in children's neuromotor, cognitive and social development. Children with visual impairment attain developmental milestones at later stages and are at higher risk of developing psychological disorders and social withdrawn.

AIMS

We performed a scoping review to summarize the mostly used instruments assessing the impact of visual impairment on quality of life, functioning and participation of children and adolescents. In addition, the main findings of the included studies are discussed.

METHODS AND PROCEDURES

We searched for papers assessing quality of life, functioning and participation of children and adolescents with visual impairment from 0 to 18 years old conducted between 2000 and 2023.

OUTCOMES AND RESULTS

In total, 69 studies met the inclusion criteria and were included in the review. Child self-report, caregivers-proxy and self-report questionnaires as well as interviews were used. The results showed that quality of life, functioning and participation are significantly reduced in children and adolescents with visual impairment, and that the impact depends on different factors (e.g., severity of the impairment, age).

CONCLUSIONS AND IMPLICATIONS

Considering the significant impact of visual impairment on quality of life, functioning and participation on this population, it is fundamental to develop integrated and multi-dimensional assessment programs that evaluate the impact of visual impairment on those dimensions considering different contexts of life (e.g., family, school, leisure time). WHAT THIS PAPER ADDS?: The present review aims to give an overview of what is known about the impact of visual impairment on quality of life, functioning and participation of children and adolescents. We assumed a biopsychosocial perspective which, in line with the definition of health by the International Classification of Functioning, Disability and Health (WHO, 2001), considered how body functions and structures, functioning, participation and environmental factors dynamically interact to define the health, or the disease, status of a person at a certain moment of life. We reported the most used instruments for the assessment of quality of life, participation, and functioning, with a specific interest on Patient-Reported Outcome Measures and self-report measures. By reporting the different instruments used, we gave a broad overview about the available tools that can be used in clinical as well as in research field to assess quality of life, functioning and participation in this population. Additionally, the review of the existing literature allowed us to demonstrate that those dimensions are negatively impacted by visual impairment and thus they should be considered in the assessment programs. Specifically, there is the need to provide more integrated assessment programs that investigate the impact of visual impairment on children and adolescents' social and emotional wellbeing, everyday functioning and social relationship, considering their subjective experience together with the one of caregivers, teachers, health care professionals, and other relevant adults involved in their life. Additionally, it is essential to plan and implement multidimensional assessment programs that consider how all areas of life are differently impacted by visual impairment.

Health-related quality of life measurements in children and adolescents with refractive errors: A scoping review

BACKGROUND

Refractive errors, particularly myopia, are the leading visual disorders worldwide, significantly affecting the quality of life (QOL) even after correction. This scoping review focuses on health-related quality of life (HRQOL) measurements for children and adolescents with refractive errors.

MAIN TEXT

We explored generic and disease-specific HRQOL tools, examining their content, psychometric properties, and the impact of various interventions on QOL. Two English databases-PubMed, Embase, and one Chinese database, CNKI, were searched for relevant studies published from January 2001 to October 2023. Inclusion criteria encompassed studies using standardized instruments to assess the QOL of children aged 0-18 with refractive errors. The review compares prevalent HRQOL measurements, analyzes children's refractive error assessments, and discusses intervention effects on patient QOL.

CONCLUSIONS

The study underlines the necessity of developing disease-specific QOL instruments for very young children and serves as a practical guide for researchers in this field. The findings advocate for a targeted approach in HRQOL assessment among the pediatric population, identifying critical gaps in current methodologies.

Refractive error and vision related quality of life

BACKGROUND

To investigate and compare the vision-related quality of life (QOL) in different types of refractive error (RE).

METHODS

This cross-sectional study was performed on 200 subjects, categorized into four groups of 50 each, consisting of subjects with myopia, hyperopia, astigmatism, and emmetropia, the latter being the control group. The mean age of the participants was 23.88 ± 5.87 (range, 15 to 38: 110 females and 90 males). RE was defined as myopia, spherical equivalent (SE) < -0.25 diopters (D), hyperopia, SE > + 0.25 D, astigmatism, cylinder < -0.25 D, and emmetropia (-0.25 ≤ SE(D) ≤ + 0.25, cylinder ≥ -0.25). Groups are subdivided into very low magnitudes of RE (0.50 and 0.75) and significant RE (1.00 ≤). Vision-related QOL was assessed using the Persian version of the 25-item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25). The NEI-VFQ was scored as visual function and socioemotional scales using Rasch analysis.

RESULTS

Corrected myopia, astigmatism, uncorrected myopia, and hyperopia had a lower vision-related QOL than emmetropes. (P < 0.001). Vision-related QOL in myopic subjects was lower than that in astigmatic participants. Very low myopes, who often do not use correction, had a significantly lower QOL than other groups.

CONCLUSION

Individuals with refractive errors experience a lower QOL score than those without. Notably, the adverse impact on QOL score is significantly greater in myopic cases, particularly very low myopia, compared to other refractive errors. Therefore, it is strongly recommended not to neglect managing very low myopia since it may improve participants' QOL.

Impact of Vision Impairment and Ocular Morbidity and Their Treatment on Quality of Life in Children: A Systematic Review

TOPIC

This review summarizes existing evidence of the impact of vision impairment and ocular morbidity and their treatment on children's quality of life (QoL).

CLINICAL RELEVANCE

Myopia and strabismus are associated with reduced QoL among children. Surgical treatment of strabismus significantly improves affected children's QoL.

METHODS

We conducted a systematic review and meta-analysis by screening articles in any language in 9 databases published from inception through August 22, 2022, addressing the impact of vision impairment, ocular morbidity, and their treatment on QoL in children. We reported pooled standardized mean differences (SMDs) using random-effects meta-analysis models. Quality appraisal was performed using Joanna Briggs Institute and National Institutes of Health tools. This study was registered with the International Prospective Register of Systematic Reviews (identifier, CRD42021233323).

RESULTS

Our search identified 29 118 articles, 44 studies (0.15%) of which were included for analysis that included 32 318 participants from 14 countries between 2005 and 2022. Seventeen observational and 4 interventional studies concerned vision impairment, whereas 10 observational and 13 interventional studies described strabismus and other ocular morbidities. Twenty-one studies were included in the meta-analysis. The QoL scores did not differ between children with and without vision impairment (SMD, -1.04; 95% confidence interval [CI], -2.11 to 0.03; P = 0.06; 9 studies). Myopic children demonstrated significantly lower QoL scores than those with normal vision (SMD, -0.60; 95% CI, -1.09 to -0.11; P = 0.02; 7 studies). Children with strabismus showed a significantly lower QoL score compared with those without (SMD, -1.19; 95% CI, -1.66 to -0.73; P < 0.001; 7 studies). Strabismus surgery significantly improved QoL in children (SMD, 1.36; 95% CI, 0.48-2.23; P < 0.001; 7 studies). No randomized controlled trials (RCTs) concerning refractive error and QoL were identified. Among all included studies, 35 (79.5%) were scored as low to moderate quality; the remaining met all quality appraisal tools criteria.

DISCUSSION

Reduced QoL was identified in children with myopia and strabismus. Surgical correction of strabismus improves the QoL of affected children, which supports insurance coverage of strabismus surgery. Further studies, especially RCTs, investigating the impact of correction of myopia on QoL are needed.

FINANCIAL DISCLOSURE(S)

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

Iris colour and subjective emotional status in Chinese adolescents

BACKGROUND

Understanding the iris colour might be a useful biomarker in predicting emotional health status. We aimed to examine the relationship of iris colour with subjective emotional status in a sample of Chinese adolescents aged 13 to 14 years.

METHODS

A total of 2346 students from ten middle schools in Mojiang participated the examination. The emotional health status was measured by the adolescent self-reported PedsQL 4.0. We obtained standardized slit-lamp photographs and developed a grading system assessing iris colour (higher grade denoting darker). Logistic regression models were fitted to assess the relationship between iris colour and emotional status.

RESULTS

The trend of decreasing negative emotional status with darker iris colour was significantly. Compared with grades 1 and 2 of iris colour, the students with grades 4 and 5 had less negative emotional status (ORfear = 0.56, 95 % CI: 0.41, 0.76; ORsadness = 0.67, 95 % CI: 0.49, 0.92; ORanger = 0.71, 95 % CI: 0.52, 0.98). In addition, the trend did not change after adjusting for potential confounders, including height, waist circumstance, sleep habits and computer times in logistic regression models.

LIMITATIONS

Only negative emotional indexes were selected as evaluative materials, it is unclear whether the pattern found in the present study also exists with regard to positive emotional indexes, such as happiness.

CONCLUSION

Darker iris colour might be associated with less negative emotional status in Chinese adolescents.

Implementing a digital comprehensive myopia prevention and control strategy for children and adolescents in China: a cost-effectiveness analysis

Background

Children and adolescents' myopia is a major public problem. Although the clinical effect of various interventions has been extensively studied, there is a lack of national-level and integral assessments to simultaneously quantify the economics and effectiveness of comprehensive myopia prevention and control programs. We aimed to compare the cost-effectiveness between traditional myopia prevention and control strategy, digital comprehensive myopia prevention and control strategy and school-based myopia screening program in China.

Methods

A Markov model was used to compare the cost-utility and cost-effectiveness among school-based myopia screening, traditional myopia prevention and control strategy, and digital comprehensive myopia prevention and control strategy among 6 to 18-year-old rural and urban schoolchildren. Parameters were collected from published sources. The primary outcomes were quality-adjusted life-year, disability-adjusted life-year, incremental cost-utility ratio, and incremental cost-effectiveness ratio. Extensive sensitivity analyses were performed to test the robustness and sensitivity of base-case analysis.

Findings

Compared with school-based myopia screening strategy, after implementing digital comprehensive myopia prevention and control strategy, the prevalence of myopia among 18-year-old students in rural and urban areas was reduced by 3.79% and 3.48%, respectively. The incremental cost-utility ratio per quality-adjusted life-year gained with the digital myopia management plan ($11,301 for rural setting, and $10,707 for urban setting) was less than 3 times the per capita gross domestic product in rural settings ($30,501) and less than 1 time the per capita gross domestic product in urban settings ($13,856). In cost-effectiveness analysis, the incremental cost-effectiveness ratio produced by digital comprehensive myopia management strategy ($37,446 and $41,814 per disability-adjusted life-year averted in rural and urban settings) slightly exceeded the cost-effectiveness threshold. When assuming perfect compliance, full coverage of outdoor activities and spectacles satisfied the cost-effectiveness threshold, and full coverage of outdoor activities produced the lowest cost ($321 for rural settings and $808 for urban settings).

Interpretations

Health economic evidence confirmed the cost-effectiveness of promoting digital comprehensive myopia prevention and control strategies for schoolchildren at the national level. Sufficient evidence provides an economic and public health reference for further action by governments, policy-makers and other myopia-endemic countries.

Funding

National Natural Science Foundation of China, NSFC (82171051), Beijing Natural Science Foundation (JQ20029), Capital Health Research and Development of Special (2020-2-1081), National Natural Science Foundation of China, NSFC (82071000), National Natural Science Foundation of China, NSFC (8197030562).

Identification of high-risk patterns of myopia in Chinese students based on four major behavioral risk factors: a latent class analysis

BACKGROUND

Myopia is prevalent in children and adolescents. Understanding the effect of multiple behaviors and their latent patterns on ocular biometric parameters may help clinicians and public health practitioners understand the behavioral risk pattern of myopia from a person-centered perspective. The purpose of this study was to identify the patterns of four major behavioral risk factors associated with myopia, including time spent outdoors, digital screen time, sleep duration, and performance of Chinese eye exercises. The study also examined the relationships between these behavioral patterns and myopia as well as ocular biometric parameters in a sample of Chinese college students.

METHODS

This study included 2014 students from the Dali University Students Eye Health Study. The average age of the subjects was 19.0 ± 0.9 years old, ranging from 15.7 to 25.1 years old. Each participant's refractive status was measured using an autorefractor without cycloplegia and ocular biometric parameters were measured using an IOL Master. Behavioral risk factors were collected using a pre-designed self-administered questionnaire. Latent class analysis (LCA) was performed to identify cluster patterns of various behaviors.

RESULTS

The prevalence of myopia was 91.8% in this population. The 2-class model was selected for the LCA based on goodness-of-fit evaluation metrics. Among the overall study sample, 41.1% and 58.9% were assigned into the high-risk and low-risk class, respectively. The risk of myopia [odds ratio (OR) = 2.12, 95% confidence interval (CI) = 1.52-3.14], high myopia (OR = 1.43, 95% CI = 1.14-1.78) and axial length/corneal radius (AL/CR) ratio of more than 3.0 (OR = 1.82, 95% CI = 1.22-2.72) were significantly higher in the high-risk compared with low-risk class.

CONCLUSIONS

Chinese university students showed differential risks of myopia and could be subdivided into high- and low-risk clusters based on four behavioral variables.

Factors associated with sleep disorders among adolescent students in rural areas of China

Background

This study aimed to determine sleep patterns and the prevalence and association factors of sleep disorders in a regionally representative sample in Mo Jiang, China.

Methods

A total of 2,346 (participation rate 93.5%) Grade 7 students (aged 13-14 years) from 10 middle schools, including 1,213 (51.7%) boys and 1,133 (48.3%) girls, participated in the study. All the participants were invited to complete questionnaires that acquired information on sleep patterns, academic performance, academic stress, and sociodemographic factors. Sleep disorders were assessed using the Chinese version of the Children's Sleep Habits Questionnaire. Logistic regression models were used to investigate factors associated with sleep disorders.

Results

The prevalence of sleep disorders among rural adolescents was 76.4%, which is higher than that among urban adolescents. Compared with previous findings in urban areas, our results indicate that sleep loss is much more severe in rural adolescents. Sleep disorders were positively associated with factors, such as watching TV [odds ratio (OR) = 1.22, p = 0.001], academic performance (OR = 1.80, p < 0.001), and academic stress (OR = 1.38, p = 0.04). In addition, girls were more likely to suffer from sleep disorders than boys (OR = 1.36, p = 0.01).

Conclusion

Insufficient sleep and sleep disorders have become common health problems in rural Chinese adolescents.

Smartphone-Acquired Anterior Segment Images for Deep Learning Prediction of Anterior Chamber Depth: A Proof-of-Concept Study

Purpose

To develop a deep learning (DL) algorithm for predicting anterior chamber depth (ACD) from smartphone-acquired anterior segment photographs.

Methods

For algorithm development, we included 4,157 eyes from 2,084 Chinese primary school students (aged 11–15 years) from Mojiang Myopia Progression Study (MMPS). All participants had with ACD measurement measured with Lenstar (LS 900) and anterior segment photographs acquired from a smartphone (iPhone Xs), which was mounted on slit lamp and under diffuses lighting. The anterior segment photographs were randomly selected by person into training (80%, no. of eyes = 3,326) and testing (20%, no. of eyes = 831) dataset. We excluded participants with intraocular surgery history or pronounced corneal haze. A convolutional neural network was developed to predict ACD based on these anterior segment photographs. To determine the accuracy of our algorithm, we measured the mean absolute error (MAE) and coefficient of determination (R²) were evaluated. Bland Altman plot was used to illustrate the agreement between DL-predicted and measured ACD values.

Results

In the test set of 831 eyes, the mean measured ACD was 3.06 ± 0.25 mm, and the mean DL-predicted ACD was 3.10 ± 0.20 mm. The MAE was 0.16 ± 0.13 mm, and R² was 0.40 between the predicted and measured ACD. The overall mean difference was −0.04 ± 0.20 mm, with 95% limits of agreement ranging between −0.43 and 0.34 mm. The generated saliency maps showed that the algorithm mainly utilized central corneal region (i.e., the site where ACD is clinically measured typically) in making its prediction, providing further plausibility to the algorithm's prediction.

Conclusions

We developed a DL algorithm to estimate ACD based on smartphone-acquired anterior segment photographs. Upon further validation, our algorithm may be further refined for use as a ACD screening tool in rural localities where means of assessing ocular biometry is not readily available. This is particularly important in China where the risk of primary angle closure disease is high and often undetected.

Association of Myopia and Genetic Variants of TGFB2-AS1 and TGFBR1 in the TGF-β Signaling Pathway: A Longitudinal Study in Chinese School-Aged Children

Background

Myopia is a complex multifactorial condition which involves several overlapping signaling pathways mediated by distinct genes. This prospective cohort study evaluated the associations of two genetic variants in the TGF-β signaling pathway with the onset and progression of myopia and ocular biometric parameters in Chinese school-aged children.

Methods

A total of 556 second grade children were examined and followed up for 3.5 years. Non-cycloplegic refraction and ocular biometric parameters were measured annually. Multivariate regression analysis was used to assess the effect of the TGFBR1 rs10760673 and TGFB2-AS1 rs7550232 variants on the occurrence and progression of myopia. A 10,000 permutations test was used to correct for multiple testing. Functional annotation of single nucleotide polymorphisms (SNPs) was performed using RegulomeDB, HaploReg, and rVarBase.

Results

A total of 448 children were included in the analysis. After adjustments for gender, age, near work time and outdoor time with 10,000 permutations, the results indicated that the C allele and the AC or CC genotypes of rs7550232 adjacent to TGFB2-AS1 were associated with a significantly increased risk of the onset of myopia in two genetic models (additive: P’ = 0.022; dominant: P’ = 0.025). Additionally, the A allele and the AA or AG genotypes of rs10760673 of TGFBR1 were associated with a significant myopic shift (additive: P’ = 0.008; dominant: P’ = 0.028; recessive: P’ = 0.027). Furthermore, rs10760673 was associated with an increase in axial length (AL) (P’ = 0.013, β = 0.03) and a change in the ratio of AL to the corneal radius of curvature (AL/CRC) (P’ = 0.031, β = 0.003). Analysis using RegulomeDB, HaploReg, and rVarBase indicated that rs7550232 is likely to affect transcription factor binding, any motif, DNase footprint, and DNase peak.

Conclusion

The present study indicated that rs10760673 and rs7550232 may represent susceptibility loci for the progression and onset of myopia, respectively, in school-aged children. Associations of the variants of the TGFBR1 and TGFB2-AS1 genes with myopia may be mediated by the TGF-β signaling pathway; this hypothesis requires validation in functional studies. This trial was registered as ChiCTR1900020584 at www.Chictr.org.cn.

IMI Impact of Myopia

The global burden of myopia is growing. Myopia affected nearly 30% of the world population in 2020 and this number is expected to rise to 50% by 2050. This review aims to analyze the impact of myopia on individuals and society; summarizing the evidence for recent research on the prevalence of myopia and high myopia, lifetime pathological manifestations of myopia, direct health expenditure, and indirect costs such as lost productivity and reduced quality of life (QOL). The principal trends are a rising prevalence of myopia and high myopia, with a disproportionately greater increase in the prevalence of high myopia. This forecasts a future increase in vision loss due to uncorrected myopia as well as high myopia-related complications such as myopic macular degeneration. QOL is affected for those with uncorrected myopia, high myopia, or complications of high myopia. Overall the current global cost estimates related to direct health expenditure and lost productivity are in the billions. Health expenditure is greater in adults, reflecting the added costs due to myopia-related complications. Unless the current trajectory for the rising prevalence of myopia and high myopia change, the costs will continue to grow. The past few decades have seen the emergence of several novel approaches to prevent and slow myopia. Further work is needed to understand the life-long impact of myopia on an individual and the cost-effectiveness of the various novel approaches in reducing the burden.

Iris surface features and anterior chamber depth in Chinese adolescents

Background

We aim to determine the association of iris surface features including crypts, color and contraction furrows with anterior chamber depth (ACD) in a school-based sample of Chinese teenagers.

Methods

Totally, 2346 students aged 13 to 14 years in Mojiang located in the Southwestern part of China contributed to this analysis. Iris surface features were graded based on standardized slit-lamp photographs. Ocular biometric parameters including ACD were measured using an IOL Master. Generalized estimating equation was incorporated in the linear regression models to assess the relationship between iris surface features and ACD.

Results

A significant trend of increasing ACDs with more contraction furrows were observed. On average, the mean ACD was 3.03 mm in participants with contraction furrows of grade 1 while it was 3.10 mm in those with grade 3 (mean difference, 0.07 mm, P = 0.01). Adjusting for other potential confounders such as gender, height and weight did not significantly changed the associations. Compared with individuals with contraction furrows of grade 1, those with grade 3 had a greater ACD of 0.06 mm (95% confidence interval: 0.01, 0.11) in multivariate-adjusted model. There were no significant relationships between ACD and iris crypts or color. (P > 0.10).

Conclusions

More iris contraction furrows are associated with greater ACDs while the association with iris color and crypts were not significant.

Associations of outdoor activity and screen time with adiposity: findings from rural Chinese adolescents with relatively low adiposity risks

Background

Whether and to what extent outdoor activity and screen time are relevant to adiposity among rural adolescents remain largely unknown as most of relevant evidence was generated from high-income countries and urban areas. This study aimed to investigate associations of outdoor activity and screen time with adiposity among early adolescents living in rural southwest China.

Methods

In this cross-sectional study, seventh graders (n = 2264) were recruited from 10 middle schools of a rural county. Overweight and obesity was assessed using adolescents’ body mass index and waist circumference. Adolescents’ outdoor activity and screen time were measured using self-reported daily time spending on outdoor activity, watching TV, playing video games, and computers on weekdays and weekends, respectively.

Results

The prevalence of overweight/obesity and high waist circumferences were 8.0 and 4.9% and were higher among those from one-child families and with parents having high school or higher education and whose fathers were not farmers. Adolescents who did not have ≥1 h outdoor activity on weekdays were more likely to be overweight/obese (OR: 1.86, 95% CI: 1.30, 2.66) and have high waist circumferences (OR: 2.22, 95%CI: 1.39, 3.57). Adolescents who had > 2 h screen time on weekends were more likely to have high waist circumferences (OR: 2.08, 95% CI: 1.14, 3.80). Lack of outdoor activity and excessive screen time also showed synergistic effects on overweight/obesity (OR: 1.93. 95% CI: 1.15, 3.24) and high waist circumferences (OR: 3.02, 95% CI: 1.54, 5.94).

Conclusions

Lack of outdoor activity and excessive screen time were relevant to adiposity among rural Chinese adolescents even when the obesity prevalence was low. Efforts to promote active lifestyles may help prevent rural adolescents from losing their advantage in the era of the global obesity epidemic.

Measuring health-related quality of life in elementary and secondary school students using the Chinese version of the EQ-5D-Y in rural China

BACKGROUND

To measure health-related quality of life (HRQOL) of elementary and secondary school students in rural China using the simplified Chinese version of the EQ-5D-Y.

METHOD

Both the samples of students were from a school-based cohort study in a county located in southwestern China. The students self-completed the EQ-5D-Y. Feasibility was evaluated according to the percentages of missing values. Known group validity was assessed by comparing the frequency of reporting EQ-5D-Y problems between groups known to differ in health status.

RESULTS

A total of 1728 elementary students and 2116 secondary students were included in the analysis. Their respective mean age was 8.7 (range: 7-15) years and 14.8 (range: 11-18) years, with girls being 45.1 and 50.1%, respectively. The missing values in both samples were quite low. Elementary students were less likely to have problems on'having pain or discomfort' and 'feeling worried, sad or unhappy' dimensions, but more likely to report problems on the dimensions related to physical functioning. Gender difference in HRQOL was only detected for secondary students in terms of 'doing usual activities', 'having pain or discomfort,' and 'feeling worried, sad or unhappy' (P < 0.05 for all). The significant differences in HRQOL were not observed for the other characteristics.

CONCLUSIONS

It appears that the EQ-5D-Y is feasible and valid instrument in school-aged children and adolescents in rural China; but it suffers from similar disadvantages to those found in other general populations. The HRQOL distributions measured by the EQ-5D-Y were also provided.

Distribution and Determinants of Peripapillary Retinal Nerve Fiber Layer Thickness and Its Association with Sleep Quality in Chinese Teenagers

Purpose

We aimed to evaluate the distribution and determinants of peripapillary retinal nerve fiber layer (pRNFL) thickness and its associations with general sleep quality in Chinese school students.

Methods

1063 grade 7 students aged 13 to 14 years with pRNFL thickness data from a school-based study on grade 7 students in Southwestern China participated in the study. The pRNFL thickness was measured on the optical coherence tomography images of a circular scan centered on the optic disc. Refractive error was measured after cycloplegia using an autorefractor and biometric parameters including axial length (AL) were measured by an IOLMaster. Participants' sleep quality was measured by the Children's Sleep Habits Questionnaire (CSHQ).

Results

The mean pRNFL thickness was 106.8 ± 10.7 μm among the 1063 participants. There was an increasing trend of spherical equivalent and a decreasing trend of AL with RNFL thickness. In multivariate analysis, each diopter of spherical equivalent increase was associated with 0.64 μm increase in pRNFL thickness. Girls had an increased mean pRNFL thickness compared with boys with a mean difference of 1.65 μm. Per 10 μm increase in pRNFL thickness was significantly associated with a 0.5 reduction in CSHQ score (better sleep quality).

Conclusions

More myopic refractive error was the major ocular determinant of decreased pRNFL thickness. In addition, students with thinner pRNFL tended to have a worse sleep quality.

The Lack of Association of Breastfeeding and Myopia in Children and Adolescents: Finding from a School-Based Study and a Meta-Analysis of the Literature

Background: We aimed to assess the relationship between breastfeeding and myopia in a school-based study in rural China. In addition, we performed a systematic review and meta-analysis to confirm the association from available observational studies. Materials and Methods: The school-based study of 2,346 grade 7 students (mean age: 13.8 years) was conducted in southwestern part of China. Myopia was defined as spherical equivalent of less than -0.50 diopter and information regarding breastfeeding was ascertained through a questionnaire. We also performed the literature search in three databases (PubMed, EMBASE, and Cochrane Central Register of Controlled Trials) and reference lists of retrieved studies. Effect estimates were pooled using random-effects models. Results: In our school-based study, the association between breastfeeding and myopia was marginally nonsignificant after adjusting for potential confounders, including gender, body mass index, parental myopia, time for reading and writing after school, and time outdoors (odds ratio = 0.75, 95% confidence interval: 0.55-1.04, p = 0.09). In the meta-analysis of eight studies, no significant association was observed. Conclusion: Current evidence did not support that breastfeeding could reduce the risk of myopia in children and adolescents.

Central Corneal Thickness and Its Association with Birth Parameters in Chinese Adolescents

Purpose: To examine the distribution and determinants of central corneal thickness (CCT) including birth weight and gestational age in a school-based samples of Grade 7 students in rural China. Methods: 2346 (93.5%) grade 7 students with a mean age of 13.8 years participated in the study. CCT was measured for both eyes using the LenStar LS900. Information regarding birth weight and gestational age was retrieved from the participants' delivery records. A linear regression model was established to examine the relationship of birth weight, gestational age and other factors with CCT. Results: The mean CCT in this population was 534.7 µm and boys had a greater CCT compared with girls (P = .06). CCT was positively related to axial length (r = 0.056) while negatively related to anterior chamber depth (r = -0.076) and corneal power (r = -0.105) . In multivariate analyses, the cornea was 19.35µm thinner in individuals with low birth weight compared with those with normal. In addition, the cornea was 25.25µm thinner in prematurely born adolescents compared with full-term ones. The combined effect of birth weight and gestational age on CCT was not statistically significant (P for interaction = 0.12) Conclusions: Low birth weight and small gestational age are associated with thinner corneas in adolescence. This disparity across groups with different levels of birth parameters should be taken into account by future studies investigating CCT as risk factors or diagnostic tests for glaucoma.

Prevalence of amblyopia and strabismus in Hani school children in rural southwest China: a cross-sectional study

PURPOSE

To determine the prevalence rate of amblyopia and strabismus in Chinese Hani ethnic school-aged children.

METHODS

All grade 1 and grade 7 students in Mojiang Hani Autonomous County, located in southwest China, were invited for comprehensive eye examinations performed by experienced ophthalmologists and optometrists, including visual acuity, ocular alignment and movements, cycloplegic autorefraction, anterior segment and fundus examinations. Standard definitions of amblyopia and strabismus were applied to calculate their prevalence rate.

RESULTS

A total of 1656 (91.0% response rate) grade 1 Hani students and 1394 (92.8% response rate) grade 7 Hani students participated in the study. Amblyopia was present in 25 Hani students (0.82%, 95% CI 0.55% to 1.20%), with no significant differences in grade (p=0.42) and gender (p=0.69). Among these 25 amblyopic children, 17 had unilateral amblyopia and eight had bilateral amblyopia, including 16 anisometropic, eight binocular refractive and one strabismic. Strabismus was found in 59 Hani students (1.93%, 95% CI 1.50% to 2.48%), including 47 with intermittent exotropia, six with constant exotropia, five with constant esotropia and one with unilateral superior oblique palsy. The prevalence rate of strabismus was higher in grade 7 students than grade 1 students with borderline significance (2.44%vs1.50%, p=0.07), but was similar by gender (2.16% in boys vs 1.68% in girls, p=0.36).

CONCLUSION

The prevalence of amblyopia and strabismus in Chinese Hani school children are both lower than that previously reported for Chinese Han children in China and for many other racial/ethnic populations from non-China studies. Refractive error is the major cause for amblyopia and intermittent exotropia is the primary strabismus type.

Iris Color and Lens Thickness in Chinese Teenagers

Purpose

We aimed to determine the association of iris color with lens thickness (LT) in a school-based sample of Chinese teenagers.

Methods

In total, 2346 grade 7 students, from 10 middle schools, aged 13 to 14 years in Mojiang located in Southwestern China were included in the analysis. A grading system was developed to assess iris color based on standardized slit-lamp photographs. LT was measured by the LenStar LS900. Refractive error was measured after cycloplegia using an autorefractor and ocular biometric parameters, including axial length (AL), were measured using an IOL Master.

Results

There was a significant trend of decreasing LTs with darker iris color. On average, eyes with “grade 1” (the lightest) iris color, when compared with those with “grade 5” (the darkest), had greater LTs (mean difference, 0.1 mm). After adjusting for other potential confounders including sex, height, and ALs in generalized estimating equation models, the trend was similar and did not change significantly. Compared with individuals with iris color of grade 1, those with grade 5 had a thinner lens of 0.1 mm (95% confidence interval [CI]: 0.01, 0.19) in sex-adjusted model and a 0.09 mm (95% CI: 0, 0.18) in multivariate-adjusted model.

Conclusions

Lighter iris color might be associated with greater LTs in Chinese teenagers. The biological mechanisms underlying the association warrant further clarification.

Translational Relevance

As LT is an important refractive component, knowledge on the effect of iris color on LTs may assist in the design of novel technologies, which could control refractive development.

Low prevalence of myopia among school children in rural China

Background

We aim to assess the prevalence of myopia in Chinese school children with low educational pressure and explore which factors could explain the differences in prevalence between generations.

Methods

A school-based epidemiologic study including 2432 grade 1 and 2346 grade 7 students was conducted from 2016 in rural areas of China. Each participant’s refractive status was measured before and after cycloplegia using an autorefractor and axial length (AL) was measured using an IOL Master. The questionnaires were completed by the parents or legal guardians of the children to collect detailed information regarding risk factors. Myopia was defined as spherical equivalent less than − 0.50D.

Results

Grade 7 students had a higher prevalence of myopia (29.4% vs. 2.4%; P < 0.001) and high myopia (0.4% vs. 0.1%; P < 0.001) compared with grade 1 students. Grade 7 students also had longer ALs (23.50 mm vs. 23.37 mm; p = 0.004) after adjusting for the effect of gender, height and other myopia-related risk factors. Adjustment for time spent on reading and writing after school per day led to a reduction in the excess prevalence of myopia in grade 7 students by 15.1%. In addition, adjustment for time outdoors reduced the excess prevalence of myopia in grade 7 students by 33.4%.

Conclusions

We reported a relatively lower prevalence of myopia in school students in rural China, suggesting that Chinese may not have a genetic predisposition to myopia and environmental factors may play a major role in the development of school myopia in Chinese children.