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.

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.

Photopic pupil size change in myopic orthokeratology and its influence on axial length elongation.

AIM: To explore the photopic pupil size behavior in myopic children undergoing overnight orthokeratology (ortho-k) over 1-year period and its effects on the axial elongation. METHODS: A total of 202 Chinese myopic children were enrolled in this prospective clinical trial. Ninety-five subjects in ortho-k group and eighty-eight subjects in spectacle group completed the 1-year study. Axial length (AL) was measured before enrollment and every 6mo after the start of ortho-k. The photopic pupil diameter (PPD) was determined using the Pentacam AXL and measured in an examination room with lighting of 300-310 Lx. Stepwise multiple linear regression analysis was used to identify variables contribution to axial elongation. RESULTS: Compared with spectacle group, the average 1-year axial elongation was significantly slower in the ortho-k group (0.25±0.27 vs 0.44±0.23 mm, P<0.0001). In ortho-k group, PPDs significantly decreased from 4.21±0.62 mm to 3.94±0.53 mm after 1mo of lens wear (P=0.001, Bonferroni correction) and the change lasts for 3-month visit. No significantly change during the other follow-up visits was found (P>0.05, Bonferroni correction). The 4.81 mm PPD may be a possible cutoff point in the ortho-k group. Subjects with PPD below or equal to 4.81 mm tended to have smaller axial elongation compared to subjects with PPD above 4.81 mm after 1-year period (t=-3.09, P=0.003). In ortho-k group, univariate analyses indicated that those with older age, greater degree of myopia, longer AL, smaller baseline PPD (PPDbaseline) experienced a smaller change in AL. In multivariate analyses, older age, greater AL and smaller PPDbaseline were associated with smaller increases in AL. In spectacle group, PPD tended to be stable (P>0.05, Bonferroni correction) and did not affect axial growth. CONCLUSION: PPDs experience significantly decreases at 1-month and 3-month ortho-k treatment. Children with smaller PPD tend to experience slower axial elongation and may benefit more from ortho-k.

Macular choroidal thickness in Chinese preschool children: decrease with axial length but no evident change with age.

AIM: To explore the distribution pattern of macular choroidal thickness (ChT) and its association with age as well as refractive status in Chinese preschoolers. METHODS: School-based, cross-sectional study. A total of 550 healthy preschool children aged 3 to 6 years old from 6 kindergartens were enrolled. Comprehensive ocular examinations, including measurement of visual acuity, axial length, intraocular pressure and slit-lamp examination before cycloplegia, as well as refraction measurement and swept-source optical coherence tomography (SS-OCT) examination after cycloplegia, were performed. The macular ChT in each sector of the ETDRS grid was measured by the built-in software of SS-OCT. RESULTS: The mean central ChT of the participants was 312±59 µm. The mean axial length and spherical equivalent refraction were 22.36±0.72 mm and 1.51±0.83 D, respectively. Axial length increased with age (P<0.001), while the spherical equivalent refraction was similar among different age groups. Similarly, no significant difference was observed in ChT in all sectors among different age groups (all P>0.05). The central ChT of 3-4, 5 and 6 years old children was 314±59 µm, 312±60 µm and 312±59 µm, respectively (P=0.920). No difference was observed in ChT in most of the sectors between genders. No statistical significant difference was observed among different refractive groups (all P>0.05), though the ChT of each sector seemed to be smaller in myopic children. Axial length and weight were the independent factors of central ChT. Children with longer axial length (ß=-21.184, P<0.001) and smaller weight (ß=1.502, P=0.041) tended to have thinner choroid. CONCLUSION: In preschool children, the ChT remains relatively stable with age, while a negative association between ChT and axial length existed. This will be helpful to elucidate the characteristics of ChT during the early refractive development.

The measurement of time spent outdoors in child myopia research: a systematic review.

The purpose of this article is to summarize the methods most commonly used to measure time spent outdoors and provide a comprehensive review of time and activity recording methods with the aim of encouraging the development of new methods. PubMed, Embase and the Cochrane Library were searched from Jan. 1st, 1990 to Aug. 31th, 2017. Studies including the following specific terms: "outdoor", "outside", "outdoor activity", "outside activity", "outdoor time", "outside time", and "outdoor AND measurement of time spent outdoors" were considered for this review. In total, three kinds of outdoor time measurements were discussed. Questionnaires have the longest history and are the most thoroughly revised instruments for assessing time spent outdoors, but recall bias is their most substantial drawback. Global positioning system (GPS) tracking can distinguish between indoor and outdoor locations, but its utility is limited due to several factors such as subject compatibility. Light exposure measurement devices are newly emerging, but all of these devices require good subject cooperation. Further efforts and exploration are needed to develop better methods and new tools to record exposure to the outdoors in real time. Moreover, inventing a new device by combining two or more types of devices mentioned above and using the latest technology of en ergy supplementation and autoswitching may make the best use of the advantages and bypass the disadvantages of each tool.

The control effect of orthokeratology on axial length elongation in Chinese children with myopia.

BACKGROUND: To retrospectively compare axial elongation in children with different degrees of myopia wearing spectacles and undergoing ortho-k treatment. METHODS: The medical records of 128 patients who were fitted with spectacles or orthokeratology (ortho-k) lenses in our clinic between 2008 and 2009 were reviewed. Ortho-k group comprised 65 subjects and 63 subjects wearing spectacles were included in the control group. Subjects were also divided into low-myopia, moderate-myopia and high-myopia groups, based on the basic spherical equivalent refractive error. Axial length periodically measured over 2-year of lens wear and changes in axial length were compared between treatment groups and between subgroups with different degrees of myopia. RESULTS: The control group exhibited more changes in axial length than the ortho-k group at both 12 months (0.39 ± 0.21 mm vs 0.16 ± 0.17 mm, p <0.001) and 24 months (0.70 ± 0.35 mm vs 0.34 ± 0.29 mm, p <0.001). Axial length elongation was estimated to be slower by about 51% in the ortho-k group. Similar results were found for the subgroups (49%, 59% and 46% reductions, respectively). In the group with low and moderate myopia, the annual increases in axial length were significantly different between the ortho-k and control groups during both the first ( Low myopia: 0.19 ± 0.17 mm vs 0.40 ± 0.18 mm, p = 0.001; Moderate myopia: 0.14 ± 0.18 mm vs 0.45 ± 0.22 mm, p <0.001) and second ( Low myopia: 0.18 ± 0.14 mm vs 0.32 ± 0.19 mm, p = 0.012; Moderate myopia: 0.18 ± 0.16 mm vs 0.34 ± 0.30 mm, p = 0.030) years. In the high myopia groups, significant differences were only found between the ortho-k and control groups during the first year (0.16 ± 0.18 mm vs 0.34 ± 0.22 mm, p = 0.004). The 2-year axial elongation was significantly associated with initial age (p <0.001) and treatment (p <0.001), but not with gender, initial refractive error, initial axial length, initial corneal curvature. CONCLUSIONS: This 2-year study indicates that ortho-k contact lens wear is effective for reducing myopia progression in children with low, moderate and high myopia.

[Analysis of cataract surgical rate and its influencing factors in Shanghai, China].

OBJECTIVE: To explore the cataract surgical rate (CSR) of Shanghai from 2006 to 2012 and examine its influencing factors. METHODS: As of 2003, a cataract surgery registration form had been filled by physicians after every cataract surgery in Shanghai. The local eye disease prevention team then entered the relevant information into the Shanghai Cataract Operations Database. Based upon this database, CSR of Shanghai was calculated. And the number of cataract surgeries was compared between Shanghai urban and suburban districts as well as among different medical institutions. RESULTS: The overall CSR in Shanghai increased from 1741 in 2006 to 2313 in 2012. In 2012, CSR in urban districts reached 6013 while it stood at 460 and 584 in inner and outer suburb districts respectively. The number of hospitals performing cataract surgery in urban districts was much more than that in suburbs. And the average number of cataract surgeries per hospital per year in suburbs was only one third of that (748 cases) in urban areas. The number of cataract surgeries at in private hospitals increased rapidly during the past 7 years. The number of 1921 cases was nearly twice as many as that at tertiary hospitals in 2012. Phacoemulsification surgery was the most popular surgical choice for cataract removal, accounting for 98.40% of total cataract surgeries in 2012. CONCLUSION: Until 2012, CSR in Shanghai dropped below the target of World Health Organization (WHO). A low level of CSR in suburbs is a major influencing factor for the overall level of CSR in Shanghai.

Cross-sectional investigation of visual impairing diseases in Shanghai blind children school.

BACKGROUND: The control of blindness in children is a high priority within the VISION 2020 initiative. To determine the causes of severe visual impairment and blindness in children from Shanghai Blind Children School (SBCS) can provide useful information on childhood blindness in Shanghai. METHODS: A cross-sectional investigation of students in SBCS was conducted in May 2010. The World Health Organization/Prevention of Blindness (WHO/PBL) eye examination record system for children with low vision and blindness was used. The results were further compared with the findings of two previous investigation studies conducted in 1986 and 2004, respectively in SBCS. RESULTS: Of the 146 children observed, 80 children (54.8%) were blind (best corrected best visual acuity less than 0.05), 27 children (18.5%) had severe visual impairment (best corrected visual acuity less than 0.1 but better than or equal to 0.05), and 34 children (23.3%) had moderate visual impairment (best corrected visual acuity less than 0.3 but better than or equal to 0.1). The major affected anatomic sites in the 107 children with severe visual impairment and blindness (SVI/BL) were retina (47.7%), whole globe (16.8%), optic nerve (13.1%) and lens (9.3%). The leading causes of SVI/BL were retinopathy of prematurity (ROP, 25.2%), followed by retinal dystrophy (15.9%), optic nerve atrophy (9.3%) and microphthalmos (9.3%). The two leading etiologic categories of SVI/BL were perinatal/neonatal (36.4%) and congenital/hereditary groups (29.0%). The leading cause of moderate visual impairment was aphakia after cataract surgery (congenital cataract, 44.1%). Compared with the findings in two previous investigations in SBCS, the proportion of ROP in visual impairing diseases increased, while the proportion of disorders of the lens (cataract and aphakia) significantly decreased. CONCLUSIONS: The leading cause of childhood blindness in SBCS nowadays is ROP. It is projected that without improvement in perinatal medical care that ROP will continue to be a major cause of childhood blindness.

[A prevalence investigation of blindness and vision impairment in 2009 in older adults of Dachang Blocks of Baoshan District, Shanghai, China].

OBJECTIVE: To investigate the prevalence of blindness and low vision and the leading causes of blindness in residents aged≥60 years in Dachang Blocks of Baoshan District, Shanghai, China. METHODS: A cross-sectional study was carried out by Shanghai Eye Disease Prevention & Treatment Center and the Center for Disease Control and Prevention in Baoshan District of Shanghai from October to December in 2009. Randomly cluster sampling was used to identify the adults aged≥60 years who had lived in Dachang Blocks of Baoshan District, Shanghai for more than 10 years. Presenting visual acuity (PVA) and best-corrected visual acuity (BCVA) based on autorefraction and subjective refraction were measured separately in each eye. External eye, anterior segment and ocular fundus were examined by the ophthalmologist using slit lamp-microscopes direct ophthalmoscopy and non-mydriatic digital camera. And the leading causes of visual impairment were assured. The Chi square test was used between the groups of rate comparison. RESULTS: Of 5199 enumerated subjects≥60 years of age, 87.42% (4545/5199) were examined. All subjects were urban population who were originally changed from the rural population in nearly 10 years. In this population, with best-corrected visual acuity, 30 persons were diagnosed as blindness, 145 persons were diagnosed as low vision. The prevalence of blindness and low vision were 0.67%, 3.19%, respectively. Low vision was associated with female gender. It was statistically significant difference (χ2=4.88, P<0.05). The leading causes of blindness were cataract, macular degeneration, ocular absence or atrophy, glaucoma, and diabetic retinopathy or corneal diseases. With presenting visual acuity, 39 persons were diagnosed as blindness, 401 persons were diagnosed as low vision. The prevalence of blindness and low vision were 0.86%, 8.82%, respectively. Blindness and low vision were associated with older age. The prevalence of blindness and low vision increased rapidly in aged 75 years or older people. The leading causes of blindness were cataract, uncorrected refractive error, macular degeneration, ocular absence or atrophy, glaucoma. Low vision was associated with female gender. It had statistically significant difference (χ2=13.345, P<0.01). CONCLUSIONS: In rapidly urbanized and aging community of Shanghai, cataract, uncorrected refractive error, macular degeneration were the leading causes of blindness with presenting visual acuity. The prevalence of low vision in females was higher than that of males which had statistically significant difference. These kinds of residents needed more targeted eye health education and services.