Short-term effects of sunlight exposure on fundus blood flow perfusion in children: a randomised controlled trial.

AIM: To evaluate the short-term effects of different sunlight exposure on fundus blood flow perfusion (BFP) after near work. METHODS: In this parallel randomised controlled trial, 81 students aged 7-15 with spherical equivalent refraction between -2.00 and +3.00 diopters were randomly assigned to either a low-illuminance (4k lux) group (N=40) or high-illuminance (10k lux) (N=41). Following 1 hour indoor reading, participants had sunlight exposure matching their group's intensity for 15 minutes. BFPs in the superficial retina, deep retina and choroid were measured at four time points: pre-reading, post-reading, 5th-minute and 15th-minute sunlight exposure. RESULTS: Within the initial 5 minutes of sunlight exposure, the 10k lux group showed a tendency for decreased BFP, particularly in the choroid (superficial retina: -0.2, 95% CI -0.9 to 0.5; deep retina: -0.1, 95% CI -0.6 to 0.4; choroid: -0.4, 95% CI -0.8 to 0.0), while the 4k lux group exhibited an increase (superficial retina: 0.7, 95% CI 0.1 to 1.3; deep retina: 0.3, 95% CI -0.2 to 0.8; choroid: 0.1, 95% CI -0.2 to 0.5). From 5 to 15 minutes, BFP decreased in both groups. At the 5th-minute mark, the 10k lux group exhibited a greater decrease in choroid (10k -0.4 vs 4k 0.1, p=0.051). No significant difference was observed after 15 minutes of exposure. CONCLUSION: Higher illuminance sunlight exposure can restore fundus BFP more rapidly than lower; however, duration remains pivotal. To prevent myopia, continuous sunlight exposure for over 15 minutes is recommended to aid in reinstating the fundus BFP increased by near work. TRIAL REGISTRATION NUMBER: NCT05594732.

Quantification of Fundus Tessellation Reflects Early Myopic Maculopathy in a Large-Scale Population of Children and Adolescents.

Purpose: This study investigated the distribution of fundus tessellation density (FTD) in a Chinese pediatric population and its potential in reflecting early myopic maculopathy (tessellated fundus). Methods: Participants were enrolled from kindergartens, primary schools, and middle schools, with cluster sampling in Shanghai, China. A series of ophthalmic examinations was conducted. Based on fundus photograph, FTD was quantitatively assessed using an artificial intelligence algorithm, and tessellated fundus was diagnosed by well-trained ophthalmologists. Results: A total of 14,234 participants aged four to 18 years were included, with 7421 boys (52.1%). Tessellated fundus was observed in 2200 (15.5%) participants. The median of FTD was 0.86% (range 0.0-42.1%). FTD increased with age and axial length. In the logistics regression, larger FTD was independently associated with tessellated fundus (P < 0.001). The area under curves of receiver operating characteristic curve for categorizing tessellated fundus using FTD was 0.774, and the cutoff point of FTD was 2.22%. Conclusions: The density of fundus tessellation was consistent with the severity of myopia. FTD could help diagnose the early stage of myopic maculopathy, tessellated fundus, providing a new pattern for myopia screening and detection of early myopic fundus changes. Translational Relevance: Quantification of fundus tessellation with artificial intelligence could help detect early myopic maculopathy.

Development and validation of a smartwatch algorithm for differentiating physical activity intensity in health monitoring.

To develop and validate a machine learning based algorithm to estimate physical activity (PA) intensity using the smartwatch with the capacity to record PA and determine outdoor state. Two groups of participants, including 24 adults (13 males) and 18 children (9 boys), completed a sequential activity trial. During each trial, participants wore a smartwatch, and energy expenditure was measured using indirect calorimetry as gold standard. The support vector machine algorithm and the least squares regression model were applied for the metabolic equivalent (MET) estimation using raw data derived from the smartwatch. Exercise intensity was categorized based on MET values into sedentary activity (SED), light activity (LPA), moderate activity (MPA), and vigorous activity (VPA). The classification accuracy was evaluated using area under the ROC curve (AUC). The METs estimation accuracy were assessed via the mean absolute error (MAE), the correlation coefficient, Bland-Altman plots, and intraclass correlation (ICC). A total of 24 adults aged 21-34 years and 18 children aged 9-13 years participated in the study, yielding 1790 and 1246 data points for adults and children respectively for model building and validation. For adults, the AUC for classifying SED, MVPA, and VPA were 0.96, 0.88, and 0.86, respectively. The MAE between true METs and estimated METs was 0.75 METs. The correlation coefficient and ICC were 0.87 (p < 0.001) and 0.89, respectively. For children, comparable levels of accuracy were demonstrated, with the AUC for SED, MVPA, and VPA being 0.98, 0.89, and 0.85, respectively. The MAE between true METs and estimated METs was 0.80 METs. The correlation coefficient and ICC were 0.79 (p < 0.001) and 0.84, respectively. The developed model successfully estimated PA intensity with high accuracy in both adults and children. The application of this model enables independent investigation of PA intensity, facilitating research in health monitoring and potentially in areas such as myopia prevention and control.

Effect modification of time spent outdoors on the association between early childhood overweight and myopia: a one-year follow-up study.

BACKGROUND: This study examined the moderating role of outdoor time on the relationship between overweight and myopia. METHODS: The data for this study was obtained from a prospective study in Shanghai, where non-myopic children wore wristwear and were followed up for 1 year. Eye examinations were performed at each visit. The modification effect was assessed on the additive scale using multivariable logistic regression, and relative excess risk due to interaction was used to calculate the modification effect. RESULTS: A total of 4683 non-myopic children were included with 32.20% being overweight at baseline. Following a 1-year period, 17.42% of children had myopia. When compared to those who spent <90 minutes outdoors, children who spent >120 had a relative risk of myopia onset that was reduced to 0.61. As time spent outdoors decreased, more risks of myopia onset were identified among overweight children than among normal children, the modification effect on the additive scale was -0.007, with ~70% of this effect attributed to the modifying influence of outdoor time. CONCLUSIONS: Increasing outdoor time can reduce myopia more among overweight children than normal. Future interventions should focus on outdoor activities among overweight children to reduce myopia risks.

Anisometropia and its association with refraction development in highly myopic children.

CLINICAL RELEVANCE: Anisometropia can affect visual development in children. Investigations of anisometropia in high myopes would explore potential causes related to anisometropia, highlighting the management of anisometropia in high myopia. BACKGROUND: The prevalence of anisometropia ranged from 0.6% to 4.3% in general paediatric population and from 7% to 14% in myopes. Anisometropia is regarded as an associated factor for myopia development, while myopia progression is a stimulus driving anisometropic development. The purpose of this study was to investigate the prevalence of anisometropia and its association with refraction development in Chinese children with high myopia. METHODS: In the cohort study, a total of 1,577 highly myopic (spherical equivalent ≤-5.0D) children aged 4-18 years were included. Refractive parameters (dioptre of sphere, dioptre of cylinder, corneal curvature radius, and axial length) of both eyes were measured after cycloplegia. The prevalence and degree of anisometropia were compared among refractive groups (non-parametric tests or chi-square tests), and regression analyses were used to determine associated factors of anisometropia. The statistical significance was set to P < 0.05 (two-tailed). RESULTS: In highly myopic children with a mean (standard deviation) age of 13.06 (2.80) years, the proportions of spherical equivalent anisometropia, cylindrical anisometropia and spherical anisometropia ≥1.00 D were 34.5%, 21.9% and 39.9%, respectively. There was more spherical equivalent anisometropia associated with more severe astigmatism (P for trend <0.001). In the multivariate regression analysis, more spherical equivalent anisometropia, cylindrical anisometropia and spherical anisometropia were associated with higher degrees of astigmatism (standard beta = -0.175, -0.148 and -0.191, respectively). More spherical anisometropia was associated with better spherical power (standard beta = 0.116). CONCLUSION: The proportion of anisometropia in highly myopic children was high, compared with previously reported general population, and more severe anisometropia was associated with higher degree of cylindrical power, but not spherical power.

Cutoff values of axial length/corneal radius ratio for determining myopia vary with age among 3-18 years old children and adolescents.

PURPOSE: To investigate the effectiveness and cutoffs of axial length/corneal radius (AL/CR) ratio for myopia detection in children by age. METHODS: Totally, 21 kindergartens and schools were enrolled. Non-cycloplegic autorefraction (NCAR), axial length (AL), horizontal and vertical meridian of corneal radius (CR1, CR2), and cycloplegic autorefraction were measured. Receiver operating characteristic (ROC) curve was used to obtain the effectiveness and cutoff for myopia detection. RESULTS: Finally, 7803 participants aged 3-18 years with mean AL/CR ratio of 2.99 ± 0.16 were included. Area under the ROC curve (AUC) of AL/CR ratio for myopia detection (0.958 for AL/CR1, 0.956 for AL/CR2, 0.961 for AL/CR) was significantly larger than that of AL (0.919, all P < 0.001), while AUCs of the three were similar with different cutoffs (> 2.98, > 3.05, and > 3.02). When divided by age, the ROC curves of AL/CR ratio in 3- to 5-year-olds showed no significance or low accuracy (AUCs ≤ 0.823) in both genders. In ≥ 6-year-olds, the accuracies were promising (AUCs ≥ 0.883, all P < 0.001), the cutoffs basically increased with age (from > 2.93 in 6-year-olds to > 3.07 in 18-year-olds among girls, and from > 2.96 in 6-year-olds to > 3.07 in 18-year-olds among boys). In addition, boys presented slightly larger cutoffs than girls in all ages except for 16 and 18 years old. For children aged 3-5 years, AL/CR ratio or AL combined with NCAR increased AUC to > 0.900. CONCLUSION: AL/CR ratio provided the best prediction of myopia with age-dependent cutoff values for all but preschool children, and the cutoffs of boys were slightly larger than those of girls. For preschool children, AL/CR ratio or AL combined with NCAR is recommended to achieve satisfactory accuracy. AL/CR ratio calculated by two meridians showed similar predictive power but with different cutoffs.

Normative value of hyperopia reserve and myopic shift in Chinese children and adolescents aged 3-16 years.

BACKGROUND: This research aims to generate normative values of hyperopia reserve and refractive progression as effective tools to estimate the risk of myopia. METHODS: A 1-year follow-up study was conducted among Chinese children and adolescents aged 3-16 years selected from schools and kinder gardens using cluster sampling. All participants underwent examinations including visual acuity, axial length and cycloplegic autorefraction (1% cyclopentolate). Percentiles of spherical equivalent (SE) were calculated using Lambda-Mu-Sigma (LMS) method. Age-specific refractive progression and hyperopia reserve were determined by backward calculation. RESULTS: Of 3118 participants, 1702 (54.6%) were boys with a mean baseline age of 7.30 years. The 50th percentile of SE estimated by LMS decreased from 1.04 D at 3 years to -2.04 D at 16 years in boys, while from 1.29 D to -2.81 D in girls. The 1-year refractive progression of myopes (0.81 D) was greater than that of non-myopes (0.51 D). The normative value of hyperopia reserve was 2.64 (range: 2.40 D-2.88 D) at 3 years and -0.35 (range: -0.50 to -0.17) D at 16 years, with the maximum progression of 0.35 D at the age of 6 years. CONCLUSION: Age-specific normative values of hyperopia reserve and yearly myopic shift in children and adolescents aged 3-16 years were provided, helping identify and monitor myopia and giving prevention in advance.

Add-On Effect of 0.01% Atropine in Orthokeratology Wearers for Myopia Control in Children: A 2-Year Retrospective Study.

INTRODUCTION: Orthokeratology (OK) and low-concentration atropine are recommended approaches for controlling myopia. However, children with younger age and lower myopia are more likely to experience rapid axial progression during OK or atropine monotreatment. This study aimed to assess the efficacy of OK combined with low-concentration atropine for myopia control in children over 24 months and to determine whether the effect was sustainable. METHODS: In this retrospective study, we reviewed medical records of baseline and follow-up visits from children (7-14 years) applying OK for myopia control. Sixty-eight children receiving monoorthokeratology treatment (OK group) and 68 children who received 0.01% atropine in combination with orthokeratology simultaneously (AOK group) were included. A series of ophthalmic tests at baseline were conducted, and axial length (AL) was measured every 6 months. The comparison of AL change at different visits between the two groups was performed by repeated measures multivariate analyses of variance (RM-MANOVA). RESULTS: There were no significant differences in baseline characters between the two groups (p > 0.05). The AL significantly increased over time in both groups (all p < 0.05), and the 2-year change in AOK was 0.16 mm (36%) lower than in OK (0.28 ± 0.22 mm versus 0.44 ± 0.34 mm, p = 0.001). Compared with OK group, the significant suppression of AL elongation in the AOK group was observed in 0-6, 6-12, and 12-18 month periods (suppression rate: 62.5%, 33.3%, 38.5%, respectively, p < 0.05), while there was no significant difference in the 18-24 month period (p = 0.105). The multiple regression analysis showed an interaction between age and treatment effect (interaction coefficient = 0.06, p = 0.040), indicating one year age decrease approximately associated with 0.06 mm increased retardation in AL elongation in the AOK group. CONCLUSION: The add-on effect of 0.01% atropine in OK wearers only occurred within 1.5 years, and younger children benefited more from the combination treatment.

Myopic maculopathy among Chinese children with high myopia and its association with choroidal and retinal changes: the SCALE-HM study.

AIMS: To investigate myopic maculopathy in Chinese children with high myopia and its association with choroidal and retinal changes. METHODS: This cross-sectional study included Chinese children aged 4-18 years with high myopia. Myopic maculopathy was classified by fundus photography and retinal thickness (RT) and choroidal thickness (ChT) in the posterior pole were measured by swept-source optical coherence tomography. A receiver operation curve was used to determine the efficacy of fundus factors in classifying myopic maculopathy. RESULTS: In total, 579 children aged 12.8±3.2 years with a mean spherical equivalent of -8.44±2.20 D were included. The proportions of tessellated fundus and diffuse chorioretinal atrophy were 43.52% (N=252) and 8.64% (N=50), respectively. Tessellated fundus was associated with a thinner macular ChT (OR=0.968, 95% CI: 0.961 to 0.975, p<0.001) and RT (OR=0.977, 95% CI: 0.959 to 0.996, p=0.016), longer axial length (OR=1.545, 95% CI: 1.198 to 1.991, p=0.001) and older age (OR=1.134, 95% CI: 1.047 to 1.228, p=0.002) and less associated with male children (OR=0.564, 95% CI: 0.348 to 0.914, p=0.020). Only a thinner macular ChT (OR=0.942, 95% CI: 0.926 to 0.959, p<0.001) was independently associated with diffuse chorioretinal atrophy. When using nasal macular ChT for classifying myopic maculopathy, the optimal cut-off value was 129.00 µm (area under the curve (AUC)=0.801) and 83.85 µm (AUC=0.910) for tessellated fundus and diffuse chorioretinal atrophy, respectively. CONCLUSION: A large proportion of highly myopic Chinese children suffer from myopic maculopathy. Nasal macular ChT may serve as a useful index for classifying and assessing paediatric myopic maculopathy. TRIAL REGISTRATION NUMBER: NCT03666052.

The rate of orthokeratology lens use and associated factors in 33,280 children and adolescents with myopia: a cross-sectional study from Shanghai.

OBJECTIVES: To investigate the rate of orthokeratology lens (ortho-k lens) use and its associated factors in children and adolescents with myopia. METHODS: Cross-sectional study. Children from 104 primary and middle schools in Shanghai were enrolled by cluster sampling. Ophthalmic examinations were conducted and information was obtained using questionnaires for associated factors analysis. RESULTS: A total of 72,920 children and adolescents were included, among which 32,259 were the potential population for ortho-k lens use. A total of 1021 participants used ortho-k lenses, equating to a use rate of 1.4% in the total population and 3.1% in the potential population. Age (OR 0.91, 95% CI: 0.88-0.95, p < 0.001), BMI (≥95th percentile: OR 0.48, 95% CI: 0.35-0.66, p < 0.001), age at initiation of refractive correction (≤12 years: OR 1.75, 95% CI: 1.31-2.33, p < 0.001), and parental myopia (either: OR 2.09, 95% CI: 1.58-2.75, p < 0.001; both: OR 3.94, 95% CI: 3.04-5.11, p < 0.001) were independently associated with ortho-k lens use. Of the ortho-k lenses users, 12.4% had a logMAR CVA of ≥0.3. A correction target (SE) of ≤-3.0 D (OR 2.05, 95% CI: 1.38-3.05, p < 0.001) and a sleeping duration of ≤6 h (OR 4.19, 95% CI: 2.03-8.64, p < 0.001) were factors independently associated with CVA ≥ 0.3. CONCLUSIONS: A certain proportion of children and adolescents in Shanghai chose to wear ortho-k lenses, related to the situation of parents and children themselves. Health education and follow-ups should be strengthened to ensure orthokeratology application quality.

Effect of Repeated Low-level Red Light on Myopia Prevention Among Children in China With Premyopia: A Randomized Clinical Trial.

Importance: Myopia is a global concern, but effective prevention measures remain limited. Premyopia is a refractive state in which children are at higher risk of myopia, meriting preventive interventions. Objective: To assess the efficacy and safety of a repeated low-level red-light (RLRL) intervention in preventing incident myopia among children with premyopia. Design, Setting, and Participants: This was a 12-month, parallel-group, school-based randomized clinical trial conducted in 10 primary schools in Shanghai, China. A total of 139 children with premyopia (defined as cycloplegic spherical equivalence refraction [SER] of -0.50 to 0.50 diopter [D] in the more myopic eye and having at least 1 parent with SER ≤-3.00 D) in grades 1 to 4 were enrolled between April 1, 2021, and June 30, 2021; the trial was completed August 31, 2022. Interventions: Children were randomly assigned to 2 groups after grade stratification. Children in the intervention group received RLRL therapy twice per day, 5 days per week, with each session lasting 3 minutes. The intervention was conducted at school during semesters and at home during winter and summer vacations. Children in the control group continued usual activities. Main Outcomes and Measures: The primary outcome was the 12-month incidence rate of myopia (defined as SER ≤-0.50 D). Secondary outcomes included the changes in SER, axial length, vision function, and optical coherence tomography scan results over 12 months. Data from the more myopic eyes were analyzed. Outcomes were analyzed by means of an intention-to-treat method and per-protocol method. The intention-to-treat analysis included participants in both groups at baseline, while the per-protocol analysis included participants in the control group and those in the intervention group who were able to continue the intervention without interruption by the COVID-19 pandemic. Results: There were 139 children (mean [SD] age, 8.3 [1.1] years; 71 boys [51.1%]) in the intervention group and 139 children (mean [SD] age, 8.3 [1.1] years; 68 boys [48.9%]) in the control group. The 12-month incidence of myopia was 40.8% (49 of 120) in the intervention group and 61.3% (68 of 111) in the control group, a relative 33.4% reduction in incidence. For children in the intervention group who did not have treatment interruption secondary to the COVID-19 pandemic, the incidence was 28.1% (9 of 32), a relative 54.1% reduction in incidence. The RLRL intervention significantly reduced the myopic shifts in terms of axial length and SER compared with the control group (mean [SD] axial length, 0.30 [0.27] mm vs 0.47 [0.25] mm; difference, 0.17 mm [95% CI, 0.11-0.23 mm]; mean [SD] SER, -0.35 [0.54] D vs -0.76 [0.60] D; difference, -0.41 D [95% CI, -0.56 to -0.26 D]). No visual acuity or structural damage was noted on optical coherence tomography scans in the intervention group. Conclusions and Relevance: In this randomized clinical trial, RLRL therapy was a novel and effective intervention for myopia prevention, with good user acceptability and up to 54.1% reduction in incident myopia within 12 months among children with premyopia. Trial Registration: ClinicalTrials.gov Identifier: NCT04825769.

Machine Learning-Based Integration of Metabolomics Characterisation Predicts Progression of Myopic Retinopathy in Children and Adolescents.

Myopic retinopathy is an important cause of irreversible vision loss and blindness. As metabolomics has recently been successfully applied in myopia research, this study sought to characterize the serum metabolic profile of myopic retinopathy in children and adolescents (4-18 years) and to develop a diagnostic model that combines clinical and metabolic features. We selected clinical and serum metabolic data from children and adolescents at different time points as the training set (n = 516) and the validation set (n = 60). All participants underwent an ophthalmologic examination. Untargeted metabolomics analysis of serum was performed. Three machine learning (ML) models were trained by combining metabolic features and conventional clinical factors that were screened for significance in discrimination. The better-performing model was validated in an independent point-in-time cohort and risk nomograms were developed. Retinopathy was present in 34.2% of participants (n = 185) in the training set, including 109 (28.61%) with mild to moderate myopia. A total of 27 metabolites showed significant variation between groups. After combining Lasso and random forest (RF), 12 modelled metabolites (mainly those involved in energy metabolism) were screened. Both the logistic regression and extreme Gradient Boosting (XGBoost) algorithms showed good discriminatory ability. In the time-validation cohort, logistic regression (AUC 0.842, 95% CI 0.724-0.96) and XGBoost (AUC 0.897, 95% CI 0.807-0.986) also showed good prediction accuracy and had well-fitted calibration curves. Three clinical characteristic coefficients remained significant in the multivariate joint model (p < 0.05), as did 8/12 metabolic characteristic coefficients. Myopic retinopathy may have abnormal energy metabolism. Machine learning models based on metabolic profiles and clinical data demonstrate good predictive performance and facilitate the development of individual interventions for myopia in children and adolescents.

Axial length changes in progressive and non-progressive myopic children in China.

PURPOSE: Due to pubertal development and crystalline lens compensation, axial length (AL) continues to increase among non-progressive myopic children (absolute annual spherical equivalent (SE) progression less than 0.25 diopter), but the amount is unknown. This study was to investigate the cutoff of AL change to accurately differentiate between progressive and non-progressive myopes. METHODS: A total of 8,546 myopic and treatment-naive children aged 6-10 years were enrolled from two cohort studies. AL with optical biometer and cycloplegic SE with auto refraction were evaluated at baseline and annually. Annual AL change was calculated, and the percentiles of annual axial elongation among progressive and non-progressive myopes were estimated by quantile regression with restricted cubic spline. Area under receiver-operating characteristic (ROC) curve (AUROC), positive predictive value (PPV), and negative predictive value (NPV) were applied to evaluate the accuracy of predicting progressive and non-progressive myopes. RESULTS: Among 8,546 myopic children, 603 (7.06%) were non-progressive myopes. Annual AL changes among non-progressive myopes remained stable with the median annual change being 0.25 mm, while the median for progressive myopes decreased with age from 0.58 to 0.42 mm. AUROC for distinguishing between non-progressive and progressive myopes was 0.88 and was > 0.85 for each age group. Annual AL change, the cutoff of 0.20 mm/year, had significantly high PPV and NPV in predicting progressive myopes with high proportion of progressive myopes and non-progressive myopes with low proportions of progressive myopes. CONCLUSION: Myopic children with non-progressive status had markedly less axial elongation than progressive ones. AL changes with cutoff of 0.20 mm/year could differentiate between non-progressive and progressive status and may be an alternative for evaluating progressive status.

Association between axial length elongation and spherical equivalent progression in Chinese children and adolescents.

BACKGROUND: It is generally believed that a 1-mm axial length (AL) elongation of the eye corresponds to a -3.00 D spherical equivalent (SE) progression, but this is disputed. PURPOSE: To investigate the association between AL elongation and SE progression among children and adolescents. METHODS: A prospective cohort study of 710 children and adolescents aged 6-16 years was included. Ophthalmic examinations, including cycloplegic SE, AL and corneal curvature, were performed at baseline and 1-year follow-up. The ratio of SE change (ΔSE) to AL change (ΔAL) (ΔSE/ΔAL) was calculated, and its association with age and refractive status was explored using a general linear model. RESULTS: Among all participants, 396 (55.77%) were male, with 265 (37.32%) myopes at baseline. The average 1-year ΔSE and ΔAL were 0.61 ± 0.40 D and 0.33 ± 0.22 mm, respectively. Both ΔSE and ΔAL gradually decreased with age (p < 0.001). In the general linear model analyses, age and refractive status were independently associated with ΔSE/ΔAL after adjustment for covariates (age: ß̂$$ \hat{\beta} $$  = 0.04, p < 0.05; myopia vs nonmyopia: ß̂$$ \hat{\beta} $$  = 0.28, p < 0.05). Based on the developed formula ΔSE/ΔAL = 1.74 + 0.05*age (for myopes), mean ΔSE/ΔAL in myopes increased from 2.06 D/mm in the 6-year-olds to 2.59 D/mm in the 16-year-olds. In nonmyopes, ΔSE/ΔAL = 1.33 + 0.05*age, and the ratio increased from 1.65 D/mm in the 6-year-olds to 2.18 D/mm in the 16-year-olds. CONCLUSIONS: The ratio of ΔSE/ΔAL varied with age and refractive status in children and adolescents. The age-specific ΔSE/ΔAL could be used to estimate SE progression through the actual AL change.

Effects of environmental factors on refractive development of children and adolescents in different pubertal stages / 中国学校卫生

Objective@#To explore the effect of puberty on refractive development of children and adolescents and its interaction with outdoor activities, near work and the use of electronic products, so as to provide a reference for strategies for intervening myopia.@*Methods@#Cluster sampling method was used to select 776 students aged 7-13 from a nine year consistent school in Shanghai to participate and were followed up for 2 years. All participants underwent cycloplegic refraction and ocular axial length measurement once a year, as well as pubertal development, average daily outdoor time, near work time and time of electronic products usage. The influencing factors and interaction effects of refractive parameters in different puberty stages were analyzed by generalized estimation equation.@*Results@#At baseline, 634 children participated in cycloplegic refraction, of which 350 were myopic (55.2%). There were significant differences in axial length, average daily outdoor time, near work time and time of using electronic products at different stages of puberty ( F = 4.10 ，4.24，5.54，9.20， P <0.05). There was interaction between puberty and outdoor time on axial length development ( β =0.133, P < 0.05), and the interaction between puberty and the time of near work or using electronic products was not statistically significant ( P >0.05).@*Conclusion@#Puberty may play a regulatory role in the relationship between outdoor time and refractive development among Chinese children and adolescents.

Online learning related screen use and associated factors in school aged children in Shanghai during the COVID-19 epidemic / 中国学校卫生

Objective@#To understand the online learning related screen use duration and screen types in school aged children in Shanghai during the COVID-19 epidemic.@*Methods@#Random clustering sampling was used to select 5 591 parents of students from 8 primary and junior schools that are in the sampling pool of the national myopia survey in districts of Jiading, Pudong and Baoshan in Shanghai in April 2020. Electronic questionnaire was administered to parents regarding their child s online learning related screen use.@*Results@#On average, the median weekly duration of online learning related screen use was 13.33 hours, the curricular and extracurricular parts of which were 10(8.75，16.67) and 0(0，3.33) hours, respectively. About 29.44% of investigated school aged children only used small size screen for online learning. Children in higher grades, being myopic and parents neither being myopic were associated with reporting higher weekly duration( P <0.05); children in higher grades of primary school and parents neither being myopic were associated with a higher likelihood of using small size screen for online learning( P <0.05).@*Conclusion@#At the early stage of the COVID-19 epidemic, the burden associated with online learning related screen use was high in school aged children in Shanghai. Health education regarding online learning related screen use should be addressed in parents to guide their children to use screen appropriately.

Effects of sunlike spectrum LED illumination on retinal blood perfusion in children and adolescents: a randomized controlled trial / 中国学校卫生

Objective@#To analyze the effect of sunlike spectrum LED illumination on retinal blood flow perfusion, and to explore the the correlation between sunlike spectrum LED illumination and eye health indicators in children and adolescents.@*Methods@#A randomized control double blind trial was conducted. The ordinary LED table lamp in the control group(11) and the sunlike spectrum LED table lamp in the experimental group(12) had a fitting degree of 87% and 95% with the daylighting spectrum, respectively. Two sample independent t test and multivariable linear regression model were applied to compare the changes of retinal blood perfusion before and after the trial.@*Results@#After near reading for 1 hour, the retinal capillary density in the superficial and deep layers of the subjects in the ordinary LED illumination group decreased (superficial layer: -3.05±2.04 , P <0.01; deep layer: -4.03± 4.94, P =0.02), no significant decrease was found in the sunlike spectrum LED illumination group (superficial layer: -0.59± 1.44, P =0.18; deep layer: -0.49±4.27, P =0.70). Multivariable regression analysis found that compared with ordinary LED illumination, sunlike spectrum LED illumination could significantly alleviate the decrease in capillary density in the superficial and deep retinal layers, respectively ( β =2.83, 95% CI =1.54-4.12, P <0.01; β =4.21,95% CI =0.58-7.84, P =0.02).@*Conclusion@#Sunlike spectrum LED illumination can alleviate the decrease in retinal blood perfusion caused by near work among children and adolescents, suggesting that it may delay the onset and development of myopia. Prevention and control of myopia needs to pay attention to the spectral power distribution of artificial illumination.

Study on the growth curve of uncorrected visual acuity of children and adolescents with relative safe refractive range / 中国学校卫生

Objective@#To analyze the distribution of uncorrected visual acuity in children and adolescents aged 3-18 years with relative safe refractive range, and to develop the growth curve and reference range of uncorrected visual acuity in children and adolescents of different ages, so as to provide reference for formulating the referral threshold for myopia screening practice.@*Methods@#Using cluster sampling method, 9 146 children and adolescents aged 3-18 years old in Shanghai were selected for uncorrected visual acuity, cycloplegic refraction, slit lamp and other ophthalmic examinations, and the percentiles and growth curve of uncorrected visual acuity of children and adolescents in the relative safe refractive range were fitted by LMS method. Besides, the area under the ROC curve and the sensitivity and specificity of different cut-off values were analyzed.@*Results@#The uncorrected visual acuity was skewed, with a median of 4.8. There were 4 675 individuals with safe refraction, the median of uncorrected visual acuity in which was 4.9. The LMS curve showed that the uncorrected visual acuity increased with age in the lower age group, and gradually stabilized to the best level at the age of 6-10. P 50 was 4.8 in 3-4 years old, 4.9 in 5-8 years old, 5.0 in 9 years old and above. The area under ROC curve of uncorrected visual acuity predicting refractive abnormality increased with age, with the lowest value of 0.55(95%CI=0.50-0.61) at 3 years old and the highest value of 0.95 (95%CI=0.94-0.96) at 12-18 years old. The Youden index was the highest for P25 at 3-6 years old, and the highest for P 10 at 7 years old and above. With the increase of the cut off value, the sensitivity increased and the specificity decreased.@*Conclusion@#The uncorrected visual acuity increases gradually with age, and reaches the best level after 6-10 years old. The screening effect of uncorrected visual acuity predicting refractive abnormality increased with age. It is suggested that the referral threshold of children and adolescents with abnormal uncorrected visual acuity should be set according to their ages, and P 25-P 75 can be selected according to the screening purposes.

Effects of baby-friendly practices on breastfeeding duration in China: a case-control study.

BACKGROUND: The Baby-Friendly Hospital Initiative is generally considered an effective way to promote breastfeeding. Although China has the largest number of baby-friendly hospitals in the world, research on baby-friendly practices in China is limited, and the rate of exclusive breastfeeding (EBF) at 6 months, 20.7%, compared to the 2025 global goal of 50% is low. It is, therefore, important to determine the factors that remain significant barriers to EBF in China. To explore how the key baby-friendly practices affect EBF duration in China, we used a case-control study to compare the effects of baby-friendly-related practices on both EBF and non-breastfeeding (NBF) mothers at 3 months and to investigate the effects of both single and comprehensive baby-friendly practices in promoting EBF duration at 3 months, which is one step toward EBF at 6 months. METHODS: Participants were recruited from four maternal and child health hospitals in western (Chongqing), eastern (Qingdao), southern (Liuzhou), and central China (Maanshan). A total of 421 mothers (245 in the EBF group, 176 in the NBF group) of infants aged 3 months were surveyed through a self-reported questionnaire from April 2018 to March 2019. The experience of baby-friendly practices and breastfeeding during hospitalization were assessed with yes/no questions. Socio-demographic factors that influenced breastfeeding at 3 months were analyzed using bivariate and multivariate logistic regression analyses. RESULTS: Of mothers in the EBF group, 65.57% reported engaging in at least seven baby-friendly practices compared to 47.72% of mothers in the NBF group. Significantly more mothers in the EBF group engaged in baby-friendly practices than in the NBF group. These practices included "breastfeeding within one hour after birth" (74.29% vs. 59.09%), "breastfeeding on demand" (86.48% vs. 75.00%), and "never use a pacifier" (46.53% vs. 31.25%). After adjusting for confounding variables, we found that the mothers who engaged in fewer than seven baby-friendly practices were about 1.7 times less likely to breastfeed than were those who engaged in seven or more baby-friendly practices (odds ratio [OR] 1.720, 95% confidence interval [CI] 1.106, 2.667). Further, the mothers who did not breastfeed on demand were as likely to not breastfeed up to 3 months (OR 2.263, 95% CI 1.265, 4.049), as were mothers who did not breastfeed during hospitalization (OR 4.379, 95% CI 1.815, 10.563). CONCLUSIONS: These data from hospitals in China suggest that higher compliance with baby-friendly practices may have a positive impact on EBF at 3 months, particularly in terms of promoting the implementation of breastfeeding on demand and breastfeeding during hospitalization in China.

The Possible Effects of Breastfeeding on Infant Development at 3 Months: A Case-Control Study.

Objective: To examine the influence of exclusive breastfeeding on infant development among 3-month-old infants in a Chinese population. Methods: Mothers and their 3-month-old infants were recruited from four maternal and child health hospitals from April 2018 to March 2019. Based on the infants' feeding patterns, the mother-infant dyads were divided into two groups: exclusive breastfeeding and formula feeding groups. Infant development was evaluated using the Chinese version of the Ages and Stages Questionnaires, 3rd edition (ASQ-C), and maternal depression, parenting confidence, and infant temperament were also assessed using the relevant scales/questionnaires. Multivariate logistic regression analysis was conducted to explore the effects of feeding patterns on infant development at 3 months. Results: The data from 417 mother-infant dyads were analyzed. For the breastfeeding group and formula feeding group, the risk of developmental delay measured by the ASQ-C was 4.1% (10/244) and 9.3% (16/173) respectively for the communication domain; 5.7% (14/244) and 8.1% (14/173) for problem-solving domain and 6.2% (15/244) and 12.1% (21/173) for personal-social domain, respectively. Compared with exclusive breastfeeding, formula feeding was a risk factor for delayed development of communication (adjusted odd ratio [aOR] = 2.60, 95% confidence interval [CI] = 1.42-4.75) problem-solving (aOR = 1.91, 95% CI = 1.06-3.45), and personal-social skills (aOR = 1.96, 95% CI = 1.12-3.42). Conclusions: Exclusive breastfeeding is important for infant communication, problem solving, and social interaction at the age of 3 months. Formula-fed infants may be at a higher risk of developmental delay than exclusively breast-fed infants. It is necessary to encourage mothers to establish and continuous breastfeeding.