We present the results of a cluster-randomized controlled trial that evaluates the effects of a free, center-based parenting intervention on early cognitive development and parenting practices in 100 rural villages in China. We then compare these effects to a home-based intervention conducted in the same region, using the same parenting curriculum and public service system. We find that the center-based intervention significantly improved children’s cognitive skills by 0.11 standard deviations, accompanied by increases in the material investments, time investments, and parenting skills of caregivers. The average impact of the center-based intervention, however, was approximately half that of the home-visiting intervention. Analysis of the possible mechanisms suggests that the difference in effects was driven primarily by different patterns of compliance. Although children with lower levels of initial skills at baseline benefited the most from the center-based intervention, they were less likely to participate in the program.

Keywords: Center-based parenting intervention; home-based parenting intervention; early cognitive development; randomized controlled trial; program participation

Background
The coronavirus disease (COVID-19) has been identified as the cause of an outbreak of respiratory illness in Wuhan, Hubei Province, China beginning in December 2019. As of 31 January 2020, this epidemic had spread to 19 countries with 11 791 confirmed cases, including 213 deaths. The World Health Organization has declared it a Public Health Emergency of International Concern.

Methods
A scoping review was conducted following the methodological framework suggested by Arksey and O’Malley. In this scoping review, 65 research articles published before 31 January 2020 were analyzed and discussed to better understand the epidemiology, causes, clinical diagnosis, prevention and control of this virus. The research domains, dates of publication, journal language, authors’ affiliations, and methodological characteristics were included in the analysis. All the findings and statements in this review regarding the outbreak are based on published information as listed in the references.

Results
Most of the publications were written using the English language (89.2%). The largest proportion of published articles were related to causes (38.5%) and a majority (67.7%) were published by Chinese scholars. Research articles initially focused on causes, but over time there was an increase of the articles related to prevention and control. Studies thus far have shown that the virus’ origination is in connection to a seafood market in Wuhan, but specific animal associations have not been confirmed. Reported symptoms include fever, cough, fatigue, pneumonia, headache, diarrhea, hemoptysis, and dyspnea. Preventive measures such as masks, hand hygiene practices, avoidance of public contact, case detection, contact tracing, and quarantines have been discussed as ways to reduce transmission. To date, no specific antiviral treatment has proven effective; hence, infected people primarily rely on symptomatic treatment and supportive care.

Conclusions
There has been a rapid surge in research in response to the outbreak of COVID-19. During this early period, published research primarily explored the epidemiology, causes, clinical manifestation and diagnosis, as well as prevention and control of the novel coronavirus. Although these studies are relevant to control the current public emergency, more high-quality research is needed to provide valid and reliable ways to manage this kind of public health emergency in both the short- and long-term.

Background
Daily “eye exercises,” massaging of periocular acupuncture pressure points, have been part of China’s national vision care policy in schools for some 50 years. However, the effect of eye exercises on myopia progression and eyeglasses wear has not been definitively investigated. This study evaluates the effectiveness of eye exercises on visual acuity and the propensity of rural children to wear eyeglasses.

Methods
Cohort study in 252 randomly-selected rural schools with baseline in September 2012 and follow up surveys 9 and 21 months later. Outcomes were assessed using propensity-score matching (PSM), multivariate linear regression and logistic regression to adjust for differences between children performing and not performing eye exercises.

Results
Among 19,934 children randomly selected for screening, 2374 myopic (spherical equivalent refractive error ≤ − 0.5 diopters in either eye) children (11.9%, mean age 10.5 [Standard Error 1.08] years, 48.5% boys) had VA in either eye ≤6/12 without eyeglasses correctable to > 6/12 with eyeglasses. Among these who completed the 21-month follow up, 1217 (58.2%) children reported practicing eye exercises on school days and 874 (41.8%) did not. After propensity-score matching, 1652 (79%) children were matched: 826 (50%) in the Eye Exercises group and 826 (50%) in the No Exercise group. Performing eye exercises was not associated with change in LogMAR uncorrected visual acuity and wear of eyeglasses, using either logistic regression or PSM at 9 or 21 months.

Conclusions
We found no evidence for an effect of eye exercises on change in vision or eyeglasses wear.

Providing vision care to students in rural areas may serve the purpose of poverty alleviation by improving education and health. This study aims to provide a comprehensive review of myopia studies among rural students in China and offer policy recommendations for the national myopia prevention and control plan under “Targeted poverty alleviation through education”. The results show that in rural China, 25% of primary school students and 50% of lower secondary school students are myopic. Moreover, more than 70% of rural myopic students suffer from uncorrected vision, which negatively affects student academic performance and mental health. Correcting myopia also has a significant positive impact on student academic achievement. Studies show that vision screening is an effective way to identify myopia among rural students. Providing subsidies for the families of myopic students to obtain eyeglasses, and providing incentives to teachers, can significantly improve the uptake and usage rates of eyeglasses. A county hospital-based vision center may be an effective platform for reducing children's visual impairment in rural China.

Nearly one-quarter of all children under age 2 in China are left behind in the countryside as parents migrate to urban areas for work.We use a four-wave longitudinal survey following young children from 6 to 30 months of age to provide first evidence on the effects of parental migration on development, health, and nutritional outcomes in the critical first stages of life. We find that maternal migration has a negative effect on cognitive development: migration before children reach 12 months of age reduces cognitive development by 0.3 standard deviations at age 2. Possible mechanisms include reduced dietary diversity and engagement in stimulating activities, both known to be causally associated with skill development in early life. We find no effects on other dimensions of physical and social-emotional health.

PURPOSE:
To explore the accuracy and cost-effectiveness of three vision screening models among preschool children in rural China.

METHODS:
Vision screening was carried out among children aged 4-5 years in 65 preschools in two counties in Northwest China, using Crowded Single Lea Symbols to test visual acuity. Children were assigned randomly by school to one of three screening models: screening by teachers (15 schools, 1835 children), local optometrists (30 schools, 1718 children) or volunteers (20 schools, 2183 children). Children identifying ≥2 symbols incorrectly in either eye failed screening. Accuracy of screening was compared with screenings executed by experienced optometrists among 141 children selected randomly from the three screening models. Direct and indirect costs for each model were assessed. Costs to detect a true case failed screening were estimated.

RESULTS:
The sensitivity for three models ranged from 76.9% to 87.5%, specificity from 84.9% to 86.7% and standardized positive predictive value from 83.7% to 85.7%. None differed significantly between models. The costs per case detected were $37.53, $59.14 and $52.19 for the teachers, local optometrists and volunteers. In producing the cost estimates for teacher screening and local optometrist screening models, we used a salary payment that was identical for both models (with the salary being equal to that of the optometrist). The teacher screening model was the most cost-effective.

CONCLUSION:
Accuracy of screening by teachers, local optometrists and volunteers was the same in this setting, but the use of teachers was most cost-effective, reducing the cost per case detected by almost 40%.

PURPOSE:
To assess the prevalence of visual impairment and spectacles ownership among academic and vocational upper secondary school students in rural China.

METHODS:
This cross-sectional study included 5583 students from four academic upper secondary schools (AUSSs) and two vocational upper secondary schools (VUSSs) in Mei and Qianyang counties, Baoji Prefecture, Shaanxi Province. In March and April 2016, students underwent assessment of visual acuity (VA) and completed a questionnaire regarding spectacles use and family characteristics. Students with visual impairment (presenting VA ≤6/12 in the better eye) and students needing spectacles (uncorrected VA ≤6/12 in the better eye, which could be improved to >6/12 with refraction) were identified.

RESULTS:
Among 5583 students (54% boys, mean age 16.4±1.0 years) in grades 10 and grade 11 attending AUSSs (n=4549) and VUSSs (n=1034), visual impairment was detected in 4026 students. Among the AUSS students, 3425 (75%) needed spectacles; 2551 (75%) had them. Among the VUSS students, 601 (58%) needed spectacles; this proportion was significantly smaller (P=0.004), as was the proportion who had spectacles (n=212, 35%, P<0.001), compared with the AUSS students. Multivariate analysis showed that ownership of spectacles among children who needed them was associated with worse uncorrected VA (P<0.001), male sex (P<0.001), and residence in an urban area (P<0.034). Spectacles ownership was also strongly associated with AUSS education (P<0.001).

CONCLUSION:
There is a high rate of unmet need in visual care among upper secondary school students. Lack of spectacles ownership among children who needed them was significantly associated with VUSS education.

KEYWORDS:
China; Eyeglasses; Rural population; Students; Vision disorders

Background
To assess the prevalence of visual impairment and rate of wearing spectacles in schools for children of migrant workers in Shanghai, China.

Methods
Children from grade 1 to 5 in schools for children of migrant workers were randomly chosen for ocular examinations. All children were screened for uncorrected visual acuity and presenting visual acuity. After screening, the children whose uncorrected visual acuity was 20/40 or less received ocular motility evaluation, cycloplegic refraction/non-cycloplegic refraction, and external eye, anterior segment, media, and fundus examinations.

Results
A total of 9673 children were enumerated and 9512 (98.34%) participated in this study. The prevalence of uncorrected, presenting, and best-corrected visual acuity of 20/40 or worse in the better eye were 13.33%, 11.26%, and 0.63%, respectively. The rate of wearing spectacles of the children with visual impairment in one or both eyes was 15.50%. Of these, 26.05% were wearing spectacles with inaccurate prescriptions. Refractive error was a major cause of visual impairment, accounting for 89.48% of all the visual impairment causes. Other causes of visual impairment included amblyopia accounting for 10.12%; congenital cataract, 0.1%; congenital nystagmus, 0.1%; ocular prosthesis, 0.1%; macular degeneration, 0.05%; and opaque cornea, 0.05%.

Conclusions
This is the first study of the prevalence and causes of visual impairment in schools for children of migrant workers in Shanghai, China. The visual impairment rate in schools for children of migrant workers in suburbs of Shanghai in the best eye before vision correction was lower than those of urban children in mainstream schools in Guangzhou in 2012, and higher than students in rural of Beijing in 1998 and in suburb of Chongqing in 2007. The refractive error was the principal cause of the visual impairment of the children of migrant workers. The rate of wearing spectacles was low and the percentage of inaccurate prescriptions, among those who wore spectacles, was high. Uncorrected refractive error was a significant cause of visual impairment in migrant children.

The past four decades have witnessed unprecedented economic growth and rapidly rising food demand in China. This paper provides an introduction to readers with useful information summarising the development of China’s agricultural sector and the transformation of its rural economy over the 40 years of economic reform. It is, however, impossible to cover all aspects of this recent and rich history in a single journal special issue. Nevertheless, we are of the view that these papers address the most fundamentally important and insightful topics including: land reform and rural development; technology progress and productivity growth; changing food consumption patterns; rural education and human capital accumulation; and poverty alleviation.

ABSTRACT The migration of hundreds of millions of rural Chinese workers to the city has contributed substantially to China’s economic growth since the beginning of the country’s economic reform in 1978. However, this migration has also led to societal issues, including more than 60 million left-behind children. Empirical studies that seek to measure the impact of being left-behind on academic performance have led to inconsistent results, perhaps because the effects may be different for first-parent migration (migration during the first period of time in which one parent migrates) and second-parent migration (migration when the remaining parent leaves the home). Here we have examined how school performance changes before and after the second parent out-migrates. We use a panel dataset of over 5,000 students from 72 primary schools in rural China. Using a difference-in-difference approach, supported by a placebo test, we find that second-parent migration has statistically significant negative impacts on student performance. Importantly, our data provide convincing evidence that second-parent migration has a more negative impact on academic performance than first-parent migration. Our results have broad implications for China’s future economic growth and inequality.