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Ulcerative colitis (UC) is difficult to cure and easy to relapse, leading to poor quality of life for patients. Oxymatrine (OMT) is one of the main alkaloids of Sophora flavescens Aiton, which has many effects, such as anti-inflammation, anti-oxidative stress, and immunosuppression. This study aimed to investigate whether OMT could attenuate ulcerative colitis by inhibiting the NOD-like receptor family pyrin domain containing three (NLRP3) inflammasome-mediated pyroptosis. In this study, the UC rat models were established by 2,4,6-Trinitrobenzenesulfonic acid (TNBS) in vivo, while RAW264.7 cells and peritoneal macrophages were stimulated with Lipopolysaccharides/Adenosine Triphosphate (LPS/ATP) in vitro to simulate pyroptosis models, and Western blotting (WB) and other detection techniques were applied to analyze proteins involved in the NLRP3 inflammasome pathway. Our results showed that OMT alleviated colitis ulcers and pathological damage in the TNBS-induced UC rats and exhibited an inhibitory effect on pyroptosis at the early stage of UC. In the model group, the pyroptosis reached the peak at 24 h after modeling with the contents of active-cysteine-aspartic proteases-1 (caspase-1), Gasdermin D (GSDMD)-N, and cleaved-interleukin-1 beta (IL-1β) to the highest expression level. Meanwhile, we found that OMT (80 mg kg−1) remarkably decreased the expression levels of NLRP3, active-caspase-1, and cleaved-IL-1β at 24 h in the lesion tissue from UC rats. Further experiments on cells demonstrated that OMT at concentrations of 100 and 250 μM significantly inhibited cell death caused by NLRP3 inflammasome activation (p < 0.05), downregulated caspase-1, GSDMD, and decreased the levels of active-caspase-1, GSDMD-N, cleaved-IL-1β in RAW326.7 cells, and peritoneal macrophages. In summary, these results indicated that OMT could attenuate ulcerative colitis through inhibiting pyroptosis mediated by the NLRP3 inflammasome. The inhibition of the NLRP3 inflammasome may be a potential strategy for UC. [ABSTRACT FROM AUTHOR]

Background: Neovascular age-related macular degeneration (AMD) is responsible for the majority of severe vision loss cases and is mainly caused by choroidal neovascularization (CNV). This condition persists or recurs in a subset of patients and regresses after 5 or more years of anti-vascular endothelial growth factor (VEGF) treatment. The precise mechanisms of CNV continue to be elucidated. According to our previous studies, macrophages play a critical role in CNV. Herein, we aimed to determine the morphological changes in macrophages in CNV to help us understand the dynamic changes. Methods: Mice were subjected to laser injury to induce CNV, and lesion expansion and macrophage transformation were examined by immunofluorescence and confocal analysis. Several strategies were used to verify the dynamic changes in macrophages. Immunofluorescence and confocal assays were performed on choroidal flat mounts to evaluate the morphology and phenotype of macrophages in different CNV phases, and the results were further verified by western blotting and RT–PCR. Results: The location of infiltrated macrophages changed after laser injury in the CNV mouse model, and macrophage morphology also dynamically changed. Branching macrophages gradually shifted to become round with the progression of CNV, which was certified to be an M2 phenotypic shift. Conclusions: Dynamic changes in macrophage morphology were observed during CNV formation, and the round-shaped M2 phenotype could promote neovascularization. In general, the changes in morphology we observed in this study can help us to understand the critical role of macrophages in CNV progression and exploit a potential treatment option for CNV indicated by a shift in macrophage polarity. [ABSTRACT FROM AUTHOR]

China karst is a global hotspot of increasing vegetation cover, with ecological conservation projects being considered as the main driver. New research using global datasets also indicates that rural outmigration has contributed to increasing biomass at national scale. However, the link between rural outmigration and vegetation cover increase has not been established at regional scale, and it remains unclear as to whether increases in biomass do, in fact, improve the environmental conditions. In this study, we use local field and statistical data on population density and rocky desertification areas to study population movements and changes in aboveground biomass in relation to rocky desertification in South China karst during 2000–2017. Our results show that the urban population in this region increased by 8.3 million people between 2005 and 2015, and the rural population decreased by 4.8 million people. We find that aboveground biomass increased most in rural areas with low human pressure, and that there was an almost linear relationship between increase in biomass and rural outmigration, with the highest increase in aboveground biomass density (1.5 MgC ha−1 yr−1) observed in areas where rural outmigration was highest, and the lowest increase in aboveground biomass density (1.1 MgC ha−1 yr−1) where rural outmigration was lowest. Rocky desertification areas decreased with a higher level of rural outmigration. Using local field data, our study confirmed that rural outmigration can generate a carbon sink at regional scale by reducing rocky desertification. [ABSTRACT FROM AUTHOR]

The atmospheric CO2 growth rate (CGR) variability is largely controlled by tropical temperature fluctuations. The sensitivity of CGR to tropical temperature γ CGR T has strongly increased since 1960, but here we show that this trend has ceased. Here, we use the long-term CO2 records from Mauna Loa and the South Pole to compute CGR, and show that γ CGR T increased by 200% from 1960–1979 to 1979–2000 but then decreased by 117% from 1980–2001 to 2001–2020, almost returning back to the level of the 1960s. Variations in γ CGR T are significantly correlated with changes in precipitation at a bi-decadal scale. These findings are further corroborated by results from a dynamic vegetation model, collectively suggesting that increases in precipitation control the decreased γ CGR T during recent decades. Our results indicate that wetter conditions have led to a decoupling of the impact of the tropical temperature variation on the carbon cycle. The authors show a recent decoupling of the tropical temperature variations and the carbon cycle that is driven by wetter conditions in the tropics. [ABSTRACT FROM AUTHOR]

Mapping forests with satellite images at local to global scale is done on a routine basis, but to go beyond the mapping of forest cover and towards characterizing forests according to their types, species and use, requires a dense time‐series of images. This knowledge is important, because ecological and economic values differ between forests. A new generation of low cost very high spatial resolution satellite images and the advent of deep learning enables improved abilities for distinguishing objects based on their structure, which could potentially also be applied to map different forest classes related to type, species and use. Here we use GF‐1 images at 2 m resolution and map six forest classes including different planted species for the karst region in southwest China, covering 806,900 km2. We compare the results with field data and show that accuracies range between 78% and 90%. We show a dominance of plantations (15%) and secondary forests (70%), and only remnants of natural forests (6%). The possibility to map forest classes based on their crown structure derived from low cost very high‐resolution satellite imagery paves the road towards sustainable forest management and restoration activities, supporting the creation of connected habitats, increasing biodiversity and improved carbon storage. No temporal information is needed for our approach, which saves costs and leads to rapid results that can be updated at a high temporal frequency. [ABSTRACT FROM AUTHOR]

The karst area in southwest China is, in recent decades, one of the world's regions with the fastest vegetation growth and increase in aboveground biomass. The improvement in the ecological conditions within this region can, to a large extent, be attributed to ecological protection projects. However, it remains unclear whether the observed increase in vegetation cover could mitigate rocky desertification at large scale. In this study, we utilized information from large field campaigns in the years 2005, 2011, and 2016, supported by satellite imagery interpretation and statistics on ecological protection projects, to explore the impact of restoration efforts on rocky desertification mitigation and vegetation resilience/resistance. The results show that restoration efforts caused a net decrease of 26.14% in areas affected by rocky desertification from 2005 to 2016. The larger the restoration efforts, the stronger the decrease in rocky desertification areas, and also the vulnerability of landscapes towards desertification; the probability of rocky desertification occurring decreased almost linearly with increased restoration efforts. In addition, both vegetation resilience and resistance against climate variations increased with restoration efforts. Restoration efforts were mainly responsible for the recovery of the ecosystem, showing that human impact is the main driver for the reversal of rocky desertification. Our study provides scientific evidence on rocky desertification control being an important step towards a sustainable development of the landscapes of Southwest China. [ABSTRACT FROM AUTHOR]

Background: To evaluate quantitative changes in iris blood circulation in patients with ischemic risk.Methods: This observational case-control study included 79 patients with diabetic retinopathy (DR) and retinal vein occlusion (RVO). The RVO group included 21 patients; the monocular proliferative diabetic retinopathy (PDR) group included 19 patients; the nondiabetic retinopathy (NDR) group included 18 patients; and the healthy control group included 21 healthy controls. In the RVO group, we analyzed RVO affected eyes, RVO contralateral eyes, and healthy control eyes. We also compared eyes with PDR and contralateral eyes without PDR, patients with diabetes mellitus (DM) without DR, and healthy control eyes. The microvascular networks of the iris and retina were analyzed using optical coherence tomography angiography. The analysis included vessel area density (VAD) and vessel skeleton density (VSD) of iris and retina.Results: In the RVO group, the VAD and VSD of iris in the affected eye were higher than those in contralateral and healthy control eyes, and the VAD and VSD of contralateral eyes were higher than those of healthy control eyes. The retinal blood flow of the RVO eyes was less than that of the contralateral and healthy control eyes, but there were no difference between the contralateral eyes and healthy control eyes. The VAD and VSD of iris in PDR were larger than nonproliferative diabetic retinopathy (NPDR) and the NPDR were larger than NDR. There were no differences between NDR and healthy control eyes. Also, there were no differences among the four groups with respect to retinal blood flow.Conclusions: Compared with the retina, iris blood circulation quantitative analysis data seem to be more sensitive to ischemia and may be used as a new predictor of ischemic disease, even if further research is needed to better understand the clinical value and importance of this analysis.Trial Registration: The trial is registered with the clinical trial registration number nct03631108 . [ABSTRACT FROM AUTHOR]

Deep-ultraviolet (DUV) photodetection has garnered extensive research interest for its vital applications in many military and civil fields. In this work, we present the synthesis of a large-area two-dimensional (2D) PdTe2 multilayer, which can be directly transferred onto a GaN substrate to construct a vertical heterostructure for visible-blind DUV photodetection. Upon 265 nm light irradiation, the heterostructure displays a distinct photovoltaic behavior, enabling it to serve as a self-driven photodetector. The important photoresponse parameters, such as ${I}_{light}/{I}_{dark}$ ratio, responsivity, specific detectivity and DUV/visible (265 nm/450 nm) rejection ratio reach as high as 106, 168.5 mA/W, $5.3 \times 10^{12}$ Jones, and 104, respectively, at zero bias. The responsivity can be further enhanced to 254.6 mA/W by applying a small reverse bias of −1.0 V. In addition, the photodetector can function as a DUV light image sensor to reliably record an “H” pattern with a decent resolution. The present study paves a way for designing high-performance cost-effective DUV photodetectors towards practical optoelectronic applications. [ABSTRACT FROM AUTHOR]

Context: South China karst is undergoing large scale land-use conversions driven by reforestation projects aiming at combating land degradation. However, the spatial extent of these human induced land-use changes is largely unknown. Objectives: This study aims at quantifying land use changes in South China karst in the context of large scale restoration and reforestation projects. Results: We apply an extensive field survey on land-use mapping and find that 45,406 km2 of farmland have been converted to forest, while 41,811 km2 have been deforested (likely due to timber harvest), which corresponds to a forest expansion of 6%, and an 8% contraction of farmlands. We find that the converted areas agree well with satellite observed greening trends, explaining why South China karst is considered a global hot-spot of vegetation cover increase. In total, 43% of the farmland to forest conversions have taken place on sloping hills steeper than 25° and predominantly at larger distances from settlements. However, 19,464 km2 of the steep sloping areas were still farmland in 2016, which is 15% of the total farmland in South China karst. Conclusions: Large scale forest dynamics are observed on sloping hills. Given the low agricultural productivity but high erosion risk, considerations regarding loss of crop production and local food security must be balanced against gains in expected provisioning of ecosystem services (e.g. carbon sequestration, timber production). [ABSTRACT FROM AUTHOR]

Land use policies have turned southern China into one of the most intensively managed forest regions in the world, with actions maximizing forest cover on soils with marginal agricultural potential while concurrently increasing livelihoods and mitigating climate change. Based on satellite observations, here we show that diverse land use changes in southern China have increased standing aboveground carbon stocks by 0.11 ± 0.05 Pg C y−1 during 2002–2017. Most of this regional carbon sink was contributed by newly established forests (32%), while forests already existing contributed 24%. Forest growth in harvested forest areas contributed 16% and non-forest areas contributed 28% to the carbon sink, while timber harvest was tripled. Soil moisture declined significantly in 8% of the area. We demonstrate that land management in southern China has been removing an amount of carbon equivalent to 33% of regional fossil CO2 emissions during the last 6 years, but forest growth saturation, land competition for food production and soil-water depletion challenge the longevity of this carbon sink service. Forest management may play an important role in climate change mitigation. Here, Tong et al. combine remote sensing and machine learning modelling to map forest cover dynamics in southern China during 2002–2017, showing effects on carbon sequestration that are extensive but of uncertain longevity and possible negative impact on soil water. [ABSTRACT FROM AUTHOR]

Multiple ecological engineering projects have been implemented in semiarid and subhumid Northern China since 1978 with the purpose to combat desertification, control dust storms, and improve vegetation cover. Although a plethora of local studies exist, the effectiveness of these projects has not been studied in a systematic and comprehensive way. Here, we used multiple satellite‐based time‐series data as well as breakpoint analysis to assess shifts in leaf area index (a proxy for green vegetation cover), gross primary production, and aboveground biomass in Northern China. We documented increased vegetation growth in northwest and southeastern parts of the region, despite drought anomalies as documented by the standardized precipitation‐evapotranspiration index during 1982–2016. Significant breakpoints in leaf area index were observed for over 72.5% of the southeastern and northwestern regions, and 70.6% of these breakpoints were detected after 1999, which correspond well to the areas with the highest ecological engineering efforts. Areas with negative trends were mainly located in the Inner Mongolian Plateau, Hulun Biur, Horqin Sand Land, and urban areas. The Loess Plateau had the largest increase in vegetation growth, followed by the north parts of Northern China where biomass increased more in the provinces of Shanxi, Liaoning, Shannxi, Hebei, and Beijing than Xinjiang, Inner Mongolia, Tianjin, and Qinghai. Our results show that multiple ecological engineering projects in the region have increased vegetation cover, production, and aboveground biomass that have led to improved environmental conditions in the study area. [ABSTRACT FROM AUTHOR]

The Loess Plateau in China is prone to widespread land degradation (soil erosion, deforestation, and water loss), and therefore, ecological restoration programmes aiming to re‐establish the ecosystem by revegetation have been implemented during recent decades. Consequently, a widespread increase in vegetation cover has been reported, but the state and dynamics of forests remain largely unknown. Here, we used field and satellite data to produce annual forest probability scores at 250 × 250 m between 2001 and 2016. We classified the forest dynamics into three types: net gain, net loss, and fluctuation. Assuming that an increasing probability score reflects forest growth, we categorised the annual forest areas into different growing stages indicating the transition between planting and mature forest. In total, the area of forest increase was 48,786 km2, and the percentage of forested areas of the region changed from 8.19% to 15.82% within 16 years. In areas of forest net gain, there was a clear transition from low‐ to high‐probability forest areas, providing evidence that a general forest transition is occurring on the Loess Plateau. The method developed for continuous monitoring of forest probability scores offers a benchmarking for further decision making on ecological restoration of the region and for mapping of afforestation projects elsewhere. The findings on major forest increases demonstrate that land degradation is in fact reversible, with implications for many ecosystem services (e.g., carbon storage and provisioning of forest products). [ABSTRACT FROM AUTHOR]

Abstract: Above‐ground vegetation biomass is one of the major carbon sinks and provides both provisioning (e.g., forestry products) and regulating ecosystem services (by sequestering carbon). Continuing deforestation and climate change threaten this natural resource but can effectively be countered by national conservation policies. Here we present time series (1999–2017) derived from complementary satellite systems to describe a phenomenon of global significance: the greening of South China Karst. We find a major increase in growing season vegetation cover from 69% in 1999 to 81% in 2017 occurring over ~1.4 million km2. Over 1999–2012, we report one of the globally largest increases in biomass to occur in the South China Karst region (on average +4% over 0.9 million km2), which accounts for ~5% of the global areas characterized with increases in biomass. These increases in southern China's vegetation have occurred despite a decline in rainfall (−8%) and soil moisture (−5%) between 1999 and 2012 and are derived from effects of forestry and conservation activities at an unprecedented spatial scale in human history (~20,000 km2 yr−1 since 2002). These findings have major implications for the provisioning of ecosystem services not only for the Chinese karst ecosystem (e.g., carbon storage, water filtration, and timber production) but also for the study of global carbon cycles. [ABSTRACT FROM AUTHOR]

In this work, a hierarchical structured cobalt sulfide/cobalt basic salt nanocomposite is successfully synthesized by using cobalt basic salt nanowires as a precursor through a vapor-phase hydrothermal process. The as-obtained hierarchical structured cobalt sulfide/cobalt basic salt nanocomposite can be applied as an electrode material for supercapacitors, it exhibits a high specific capacitance of 1984 F g−1 at a current density of 1 A g−1, a good rate capability of 78.6% capacitance retention at a high current density of 20 A g−1 and an excellent cycle stability of 90.2% capacitance retention after 5000 charge–discharge cycles. The specific capacitance of the cobalt sulfide/cobalt basic salt nanocomposite is much higher than that of the cobalt basic salt. The excellent electrochemical performances of the cobalt sulfide/cobalt basic salt nanocomposite can be attributed to its unique hierarchical nanostructure. [ABSTRACT FROM AUTHOR]

A labeled green fluorescent polystyrene sulfonate (LNaPSS) has been synthesized using atom transfer radical polymerization of a styrene sulfonate monomer with a fluorescent co-monomer, fluorescein thiocyanate-vinyl aniline. As a result this 100 % sulfonated polymer contains no hydrophobic patches along the chain backbone besides the fluorescent marker itself. The concentration of the fluorescent monomer was kept low to maintain the characteristic properties of the anionic polyelectrolyte, LNaPSS. ATRP conditions facilitated the production of polymers spanning a range of molecular weights from 35,000 to 175,000 in gram-scale batches with polydispersity indices of 1.01-1.24. Molecular weight increased with the monomer to initiator ratio. Gel permeation chromatography results show a unimodal distribution, and the polymer structure was also confirmed by H NMR and FT-IR spectroscopy. Fluorescence spectroscopy confirmed covalent bonding of fluorescein isothiocyanate to the polymer, indicating that the polymer is suitable as a probe in fluorescence microscopy. To demonstrate this ability, the polymer was used to locate structural features in salt crystals formed during drying, as in the evaporation of sea mist. A second application to probe diffusion studies is also demonstrated. [ABSTRACT FROM AUTHOR]

Background: The aim of the present study was to investigate the prevalence and characteristics of primary open-angle glaucoma among the urban population of Pudong New District, Shanghai.Methods: Three residents' committees were randomly selected from Pudong New District, and residents aged 50 and older were screened for primary open-angle glaucoma (POAG) from March to April 2011. In remote screening, the tests on visual acuity, refraction, intraocular pressure (IOP), and the photographs of anterior segment and fundus were used to identify POAG suspect. The suspected subjects were then reexamined with the tests on IOP, gonioscopy, Humphrey visual field test, and retinal nerve fiber layer (RNFL) thickness by optical coherence tomography (OCT). POAG was diagnosed according to the criteria defined by International Society for Geographic and Epidemiological Ophthalmology (ISGEO). Finally, POAG risk factors were evaluated using logistic regression analysis.Results: A total of 2528 citizens out of 3,146 eligible residents (80.36 %) participated in this study. Among the citizens, 72 were diagnosed to have POAG, giving the crude prevalence rate of 2.85 % (95 % CI:2.20 %-3.50 %) in general and age- and gender-adjusted prevalence rate of 2.8 % (95 % CI: 2.78 %-2.83 %). Among the 72 POAG patients, only 22 cases had IOP exceeding 21 mmHg while other 50 cases had IOP of 21 mmHg or less; nine cases had one eye blind (12.5 %). Intriguingly, only eight cases (11.11 %) had been diagnosed with POAG before this screening.Conclusions: More efforts are required for early screening and education on POAG in communities, especially in a POAG high-risk population. [ABSTRACT FROM AUTHOR]

Availability of high-resolution satellite rainfall products provides a great opportunity to monitor precipitation frequently over large and remote areas. However, the accuracies of these products need thorough assessment before they can be widely used. The objective of this study is to evaluate the accuracies of Tropical Rainfall Measuring Mission Multisatellite Precipitation Analysis 3B42 products (TMPA V6 and TMPA V7) using a network of 75 rain gauges over Southwestern China. The study region has a complex terrain, which makes it challenging for TMPA rainfall products to give reliable estimates. The results show that the TMPA products tend to underestimate the occurrences of rainfall events. Furthermore, TMPA V6 always underestimates the precipitation, while V7 generally overestimates rainfall in wet season and underestimates it in dry season. Under- and overestimation of rainfall by the two products can be mainly attributed to false alarm events. The overall accuracies of the two products depend heavily on the time scale. At the daily scale, these products may not be reliable; however, the overall accuracies are improved substantially when the time scale is extended from daily to monthly and seasonal scales. Reliability of the TMPA precipitation estimates is also dependent on the climate zones and elevation to some extent and shows clear seasonal variations. In the wet months from May to September, the estimates for TMPA 3B42 V6 and V7 tend to be more accurate. In comparison, the accuracy of V7 is improved slightly over V6. However, V7 still has some major limitations in reproducing precipitation in dry seasons and in high-elevation regions with complex terrains, suggesting that further improvements in TMPA precipitation retrieval algorithms are still needed for this type of regions. [ABSTRACT FROM AUTHOR]

Background: To investigate the distribution of peripheral anterior chamber depth (ACD) and the relationship between peripheral ACD and gonioscopy compared to other ocular parameters for primary angle closure disease (PACD) screening. We performed a population-based survey in Pudong New District of Shanghai, China, in 2011.Methods: Cross-sectional study. Adults 50 and older were enrolled from a population-based study using cluster random sampling in Pudong New District, Shanghai. Remote ocular screening was performed with digital anterior eye structure photography. Van Herrick measurements were used to evaluate the peripheral ACD, the depth of the peripheral anterior chamber, and corneal thickness (CT), and the ACD to CT ratio was calculated. Subjects with peripheral ACD less than 0.5 CT were made follow-up appointments for clinical examination with gonioscopy. Receiver operating characteristic curves (ROC) were generated to show the performance of different tests in screening for primary angle closure disease (PACD).Results: Two thousand five hundred twenty-eight adults participated in the study with 91 patients diagnosed with PACD. Two thousand four hundred sixty-three subjects had valid data in the right eye available for analysis. The mean peripheral ACD values for men and women were significantly different: 1.04 ± 0.46 (range 0.11-2.93) CT and 0.87 ± 0.41 (range 0.12-2.96) CT respectively (t = - 4.18; P<0.0001). Multivariate logistic regression analysis reveals that peripheral ACD declined by 0.31 CT (P < 0.0001) per diopter of SE and was 0.19 CT (P < 0.0001) shallower in women than in men (r2 = 0.1304, P < 0.0001). Peripheral ACD performed best in screening for PACD.Conclusions: Peripheral ACD measurement is recommended for PACD screening in community elderly Chinese. [ABSTRACT FROM AUTHOR]

Background: To investigate the prevalence and risk factors of undercorrected refractive error (URE) among people with diabetes in the Baoshan District of Shanghai, where data for undercorrected refractive error are limited.Methods: The study was a population-based survey of 649 persons (aged 60 years or older) with diabetes in Baoshan, Shanghai in 2009. One copy of the questionnaire was completed for each subject. Examinations included a standardized refraction and measurement of presenting and best-corrected visual acuity (BCVA), tonometry, slit lamp biomicroscopy, and fundus photography.Results: The calculated age-standardized prevalence rate of URE was 16.63% (95% confidence interval [CI] 13.76-19.49). For visual impairment subjects (presenting vision worse than 20/40 in the better eye), the prevalence of URE was up to 61.11%, and 75.93% of subjects could achieve visual acuity improvement by at least one line using appropriate spectacles. Under multiple logistic regression analysis, older age, female gender, non-farmer, increasing degree of myopia, lens opacities status, diabetic retinopathy (DR), body mass index (BMI) index lower than normal, and poor glycaemic control were associated with higher URE levels. Wearing distance eyeglasses was a protective factor for URE.Conclusion: The undercorrected refractive error in diabetic adults was high in Shanghai. Health education and regular refractive assessment are needed for diabetic adults. Persons with diabetes should be more aware that poor vision is often correctable, especially for those with risk factors. [ABSTRACT FROM AUTHOR]

Background: To investigate the prevalence and risk factors of visual impairment associated with refractive error and the unmet need for spectacles in a special suburban senior population in Baoshan District of Shanghai, one of several rural areas undergoing a transition from rural to urban area, where data of visual impairment are limited.Methods: The study was a population based survey of 4545 Chinese aged (age: >60 years or older ) at Baoshan, Shanghai, in 2009. One copy of questionnaire was completed for each subject. Examinations included a standardized refraction and measurement of presenting and best corrected visual acuity (BCVA) as well as tonometry, slit lamp biomicroscopy, and fundus photography.Results: The prevalence of mild (6/12 to 6/18), moderate (6/18 to 6/60) and severe visual impairment was 12.59%, 8.38% and 0.44%, respectively, and 5.26%, 3.06% and 0.09% with refractive correction. Visual impairment was associated with age, gender, education and career, but not insurance . The prevalence of correctable visual impairment was 5.81% (using 6/18 cutoff) and 13.18% (using 6/12 cutoff). Senior people and women were significantly at a higher risk of correctable visual impairment, while the well-educated on the contrary. The prevalence of undercorrected refractive error (improves by 2 or more lines with refraction) was 24.84%, and the proportion with undercorrected refractive error for mild, moderate , severe and no visual impairment was 61.54%, 67.98%, 60.00% and 14.10%, respectively. The spectacle coverage rate was 44.12%. Greater unmet need for spectacles was observed among elderly people, females, non-peasant, and subjects with less education and astigmatism only.Conclusions: High prevalence of visual impairment, visual impairment alleviated by refractive correction, and low spectacle coverage existed among the senior population in Baoshan District of Shanghai. Education for the public of the importance of regular examination and appropriate and accessible refraction service might be helpful to solve the problem. [ABSTRACT FROM AUTHOR]