Improving axial resolution in Structured Illumination Microscopy using deep learning.

Structured Illumination Microscopy (SIM) is a widespread methodology to image live and fixed biological structures smaller than the diffraction limits of conventional optical microscopy. Using recent advances in image up-scaling through deep learning models, we demonstrate a method to reconstruct 3D SIM image stacks with twice the axial resolution attainable through conventional SIM reconstructions. We further demonstrate our method is robust to noise and evaluate it against two-point cases and axial gratings. Finally, we discuss potential adaptions of the method to further improve resolution. This article is part of the Theo Murphy meeting issue 'Super-resolution structured illumination microscopy (part 1)'.

A systematic analysis of global anemia burden from 1990 to 2010.

Previous studies of anemia epidemiology have been geographically limited with little detail about severity or etiology. Using publicly available data, we estimated mild, moderate, and severe anemia from 1990 to 2010 for 187 countries, both sexes, and 20 age groups. We then performed cause-specific attribution to 17 conditions using data from the Global Burden of Diseases, Injuries and Risk Factors (GBD) 2010 Study. Global anemia prevalence in 2010 was 32.9%, causing 68.36 (95% uncertainty interval [UI], 40.98 to 107.54) million years lived with disability (8.8% of total for all conditions [95% UI, 6.3% to 11.7%]). Prevalence dropped for both sexes from 1990 to 2010, although more for males. Prevalence in females was higher in most regions and age groups. South Asia and Central, West, and East sub-Saharan Africa had the highest burden, while East, Southeast, and South Asia saw the greatest reductions. Iron-deficiency anemia was the top cause globally, although 10 different conditions were among the top 3 in regional rankings. Malaria, schistosomiasis, and chronic kidney disease-related anemia were the only conditions to increase in prevalence. Hemoglobinopathies made significant contributions in most populations. Burden was highest in children under age 5, the only age groups with negative trends from 1990 to 2010.

Global Vision Impairment and Blindness Due to Uncorrected Refractive Error, 1990-2010.

The purpose of this systematic review was to estimate worldwide the number of people with moderate and severe visual impairment (MSVI; presenting visual acuity <6/18, ≥3/60) or blindness (presenting visual acuity <3/60) due to uncorrected refractive error (URE), to estimate trends in prevalence from 1990 to 2010, and to analyze regional differences. The review focuses on uncorrected refractive error which is now the most common cause of avoidable visual impairment globally. : The systematic review of 14,908 relevant manuscripts from 1990 to 2010 using Medline, Embase, and WHOLIS yielded 243 high-quality, population-based cross-sectional studies which informed a meta-analysis of trends by region. The results showed that in 2010, 6.8 million (95% confidence interval [CI]: 4.7-8.8 million) people were blind (7.9% increase from 1990) and 101.2 million (95% CI: 87.88-125.5 million) vision impaired due to URE (15% increase since 1990), while the global population increased by 30% (1990-2010). The all-age age-standardized prevalence of URE blindness decreased 33% from 0.2% (95% CI: 0.1-0.2%) in 1990 to 0.1% (95% CI: 0.1-0.1%) in 2010, whereas the prevalence of URE MSVI decreased 25% from 2.1% (95% CI: 1.6-2.4%) in 1990 to 1.5% (95% CI: 1.3-1.9%) in 2010. In 2010, URE contributed 20.9% (95% CI: 15.2-25.9%) of all blindness and 52.9% (95% CI: 47.2-57.3%) of all MSVI worldwide. The contribution of URE to all MSVI ranged from 44.2 to 48.1% in all regions except in South Asia which was at 65.4% (95% CI: 62-72%). : We conclude that in 2010, uncorrected refractive error continues as the leading cause of vision impairment and the second leading cause of blindness worldwide, affecting a total of 108 million people or 1 in 90 persons.

Trends in mild, moderate, and severe stunting and underweight, and progress towards MDG 1 in 141 developing countries: a systematic analysis of population representative data.

BACKGROUND: There is little information on country trends in the complete distributions of children's anthropometric status, which are needed to assess all levels of mild to severe undernutrition. We aimed to estimate trends in the distributions of children's anthropometric status and assess progress towards the Millennium Development Goal 1 (MDG 1) target of halving the prevalence of weight-for-age Z score (WAZ) below -2 between 1990 and 2015 or reaching a prevalence of 2·3% or lower. METHODS: We collated population-representative data on height-for-age Z score (HAZ) and WAZ calculated with the 2006 WHO child growth standards. Our data sources were health and nutrition surveys, summary statistics from the WHO Global Database on Child Growth and Malnutrition, and summary statistics from reports of other national and international agencies. We used a Bayesian hierarchical mixture model to estimate Z-score distributions. We quantified the uncertainty of our estimates, assessed their validity, compared their performance to alternative models, and assessed sensitivity to key modelling choices. FINDINGS: In developing countries, mean HAZ improved from -1·86 (95% uncertainty interval -2·01 to -1·72) in 1985 to -1·16 (-1·29 to -1·04) in 2011; mean WAZ improved from -1·31 (-1·41 to -1·20) to -0·84 (-0·93 to -0·74). Over this period, prevalences of moderate-and-severe stunting declined from 47·2% (44·0 to 50·3) to 29·9% (27·1 to 32·9) and underweight from 30·1% (26·7 to 33·3) to 19·4% (16·5 to 22·2). The largest absolute improvements were in Asia and the largest relative reductions in prevalence in southern and tropical Latin America. Anthropometric status worsened in sub-Saharan Africa until the late 1990s and improved thereafter. In 2011, 314 (296 to 331) million children younger than 5 years were mildly, moderately, or severely stunted and 258 (240 to 274) million were mildly, moderately, or severely underweight. Developing countries as a whole have less than a 5% chance of meeting the MDG 1 target; but 61 of these 141 countries have a 50-100% chance. INTERPRETATION: Macroeconomic shocks, structural adjustment, and trade policy reforms in the 1980s and 1990s might have been responsible for worsening child nutritional status in sub-Saharan Africa. Further progress in the improvement of children's growth and nutrition needs equitable economic growth and investment in pro-poor food and primary care programmes, especially relevant in the context of the global economic crisis. FUNDING: The Bill & Melinda Gates Foundation and the UK Medical Research Council.

Global prevalence of vision impairment and blindness: magnitude and temporal trends, 1990-2010.

PURPOSE: Vision impairment is a leading and largely preventable cause of disability worldwide. However, no study of global and regional trends in the prevalence of vision impairment has been carried out. We estimated the prevalence of vision impairment and its changes worldwide for the past 20 years. DESIGN: Systematic review. PARTICIPANTS: A systematic review of published and unpublished population-based data on vision impairment and blindness from 1980 through 2012. METHODS: Hierarchical models were fitted fitted to estimate the prevalence of moderate and severe vision impairment (MSVI; defined as presenting visual acuity <6/18 but ≥ 3/60) and the prevalence of blindness (presenting visual acuity <3/60) by age, country, and year. MAIN OUTCOME MEASURES: Trends in the prevalence of MSVI and blindness for the period 1990 through 2010. RESULTS: Globally, 32.4 million people (95% confidence interval [CI], 29.4-36.5 million people; 60% women) were blind in 2010, and 191 million people (95% CI, 174-230 million people; 57% women) had MSVI. The age-standardized prevalence of blindness in older adults (≥ 50 years) was more than 4% in Western Sub-Saharan Africa (6.0%; 95% CI, 4.6%-7.1%), Eastern Sub-Saharan Africa (5.7%; 95% CI, 4.4%-6.9%), South Asia (4.4%; 95% CI, 3.5%-5.1%), and North Africa and the Middle East (4.6%; 95% CI, 3.5%-5.8%), in contrast to high-income regions with blindness prevalences of ≤ 0.4% or less. The MSVI prevalence in older adults was highest in South Asia (23.6%; 95% CI, 19.4%-29.4%), Oceania (18.9%; 95% CI, 11.8%-23.7%), and Eastern and Western Sub-Saharan Africa and North Africa and the Middle East (95% CI, 15.9%-16.8%). The MSVI prevalence was less than 5% in all 4 high-income regions. The global age-standardized prevalence of blindness and MSVI for older adults decreased from 3.0% (95% CI, 2.7%-3.4%) worldwide in 1990 to 1.9% (95% CI, 1.7%-2.2%) in 2010 and from 14.3% (95% CI, 12.1%-16.2%) worldwide to 10.4% (95% CI, 9.5%-12.3%), respectively. When controlling for age, women's prevalence of blindness was greater than men's in all world regions. Because the global population has increased and aged between 1990 and 2010, the number of blind has increased by 0.6 million people (95% CI, -5.2 to 5.3 million people). The number with MSVI may have increased by 19 million people (95% CI, -8 to 72 million people) from 172 million people (95% CI, 142-198 million people) in 1990. CONCLUSIONS: The age-standardized prevalence of blindness and MSVI has decreased in the past 20 years. However, because of population growth and the relative increase in older adults, the blind population has been stable and the population with MSVI may have increased

Spatio-temporal estimates of HIV risk group proportions for adolescent girls and young women across 13 priority countries in sub-Saharan Africa.

The Global AIDS Strategy 2021-2026 identifies adolescent girls and young women (AGYW) as a priority population for HIV prevention, and recommends differentiating intervention portfolios geographically based on local HIV incidence and individual risk behaviours. We estimated prevalence of HIV risk behaviours and associated HIV incidence at health district level among AGYW living in 13 countries in sub-Saharan Africa. We analysed 46 geospatially-referenced national household surveys conducted between 1999-2018 across 13 high HIV burden countries in sub-Saharan Africa. Female survey respondents aged 15-29 years were classified into four risk groups (not sexually active, cohabiting, non-regular or multiple partner[s] and female sex workers [FSW]) based on reported sexual behaviour. We used a Bayesian spatio-temporal multinomial regression model to estimate the proportion of AGYW in each risk group stratified by district, year, and five-year age group. Using subnational estimates of HIV prevalence and incidence produced by countries with support from UNAIDS, we estimated new HIV infections in each risk group by district and age group. We then assessed the efficiency of prioritising interventions according to risk group. Data consisted of 274,970 female survey respondents aged 15-29. Among women aged 20-29, cohabiting (63.1%) was more common in eastern Africa than non-regular or multiple partner(s) (21.3%), while in southern countries non-regular or multiple partner(s) (58.9%) were more common than cohabiting (23.4%). Risk group proportions varied substantially across age groups (65.9% of total variation explained), countries (20.9%), and between districts within each country (11.3%), but changed little over time (0.9%). Prioritisation based on behavioural risk, in combination with location- and age-based prioritisation, reduced the proportion of population required to be reached in order to find half of all expected new infections from 19.4% to 10.6%. FSW were 1.3% of the population but 10.6% of all expected new infections. Our risk group estimates provide data for HIV programmes to set targets and implement differentiated prevention strategies outlined in the Global AIDS Strategy. Successfully implementing this approach would result in more efficiently reaching substantially more of those at risk for infections.

National, regional, and global trends in infertility prevalence since 1990: a systematic analysis of 277 health surveys.

BACKGROUND: Global, regional, and national estimates of prevalence of and tends in infertility are needed to target prevention and treatment efforts. By applying a consistent algorithm to demographic and reproductive surveys available from developed and developing countries, we estimate infertility prevalence and trends, 1990 to 2010, by country and region. METHODS AND FINDINGS: We accessed and analyzed household survey data from 277 demographic and reproductive health surveys using a consistent algorithm to calculate infertility. We used a demographic infertility measure with live birth as the outcome and a 5-y exposure period based on union status, contraceptive use, and desire for a child. We corrected for biases arising from the use of incomplete information on past union status and contraceptive use. We used a Bayesian hierarchical model to estimate prevalence of and trends in infertility in 190 countries and territories. In 2010, among women 20-44 y of age who were exposed to the risk of pregnancy, 1.9% (95% uncertainty interval 1.7%, 2.2%) were unable to attain a live birth (primary infertility). Out of women who had had at least one live birth and were exposed to the risk of pregnancy, 10.5% (9.5%, 11.7%) were unable to have another child (secondary infertility). Infertility prevalence was highest in South Asia, Sub-Saharan Africa, North Africa/Middle East, and Central/Eastern Europe and Central Asia. Levels of infertility in 2010 were similar to those in 1990 in most world regions, apart from declines in primary and secondary infertility in Sub-Saharan Africa and primary infertility in South Asia (posterior probability [pp] ≥0.99). Although there were no statistically significant changes in the prevalence of infertility in most regions amongst women who were exposed to the risk of pregnancy, reduced child-seeking behavior resulted in a reduction of primary infertility among all women from 1.6% to 1.5% (pp=0.90) and a reduction of secondary infertility among all women from 3.9% to 3.0% (pp>0.99) from 1990 to 2010. Due to population growth, however, the absolute number of couples affected by infertility increased from 42.0 million (39.6 million, 44.8 million) in 1990 to 48.5 million (45.0 million, 52.6 million) in 2010. Limitations of the study include gaps in survey data for some countries and the use of proxies to determine exposure to pregnancy. CONCLUSIONS: We analyzed demographic and reproductive household survey data to reveal global patterns and trends in infertility. Independent from population growth and worldwide declines in the preferred number of children, we found little evidence of changes in infertility over two decades, apart from in the regions of Sub-Saharan Africa and South Asia. Further research is needed to identify the etiological causes of these patterns and trends.

National, regional, and global estimates of anaemia by severity in women and children for 2000-19: a pooled analysis of population-representative data.

BACKGROUND: Anaemia causes health and economic harms. The prevalence of anaemia in women aged 15-49 years, by pregnancy status, is indicator 2.2.3 of the UN Sustainable Development Goals, and the aim of halving the anaemia prevalence in women of reproductive age by 2030 is an extension of the 2025 global nutrition targets endorsed by the World Health Assembly (WHA). We aimed to estimate the prevalence of anaemia by severity for children aged 6-59 months, non-pregnant women aged 15-49 years, and pregnant women aged 15-49 years in 197 countries and territories and globally for the period 2000-19. METHODS: For this pooled analysis of population-representative data, we collated 489 data sources on haemoglobin distribution in children and women from 133 countries, including 4·5 million haemoglobin measurements. Our data sources comprised health examination, nutrition, and household surveys, accessed as anonymised individual records or as summary statistics such as mean haemoglobin and anaemia prevalence. We used a Bayesian hierarchical mixture model to estimate haemoglobin distributions in each population and country-year. This model allowed for coherent estimation of mean haemoglobin and prevalence of anaemia by severity. FINDINGS: Globally, in 2019, 40% (95% uncertainty interval [UI] 36-44) of children aged 6-59 months were anaemic, compared to 48% (45-51) in 2000. Globally, the prevalence of anaemia in non-pregnant women aged 15-49 years changed little between 2000 and 2019, from 31% (95% UI 28-34) to 30% (27-33), while in pregnant women aged 15-49 years it decreased from 41% (39-43) to 36% (34-39). In 2019, the prevalence of anaemia in children aged 6-59 months exceeded 70% in 11 countries and exceeded 50% in all women aged 15-49 years in ten countries. Globally in all populations and in most countries and regions, the prevalence of mild anaemia changed little, while moderate and severe anaemia declined in most populations and geographical locations, indicating a shift towards mild anaemia. INTERPRETATION: Globally, regionally, and in nearly all countries, progress on anaemia in women aged 15-49 years is insufficient to meet the WHA global nutrition target to halve anaemia prevalence by 2030, and the prevalence of anaemia in children also remains high. A better understanding of the context-specific causes of anaemia and quality implementation of effective multisectoral actions to address these causes are needed. FUNDING: USAID, US Centers for Disease Control and Prevention, and Bill & Melinda Gates Foundation.

Effective refractive error coverage in adults aged 50 years and older: estimates from population-based surveys in 61 countries.

BACKGROUND: In 2021, WHO Member States endorsed a global target of a 40-percentage-point increase in effective refractive error coverage (eREC; with a 6/12 visual acuity threshold) by 2030. This study models global and regional estimates of eREC as a baseline for the WHO initiative. METHODS: The Vision Loss Expert Group analysed data from 565 448 participants of 169 population-based eye surveys conducted since 2000 to calculate eREC (met need/[met need + undermet need + unmet need]). A binary logistic regression model was used to estimate eREC by Global Burden of Disease (GBD) Study super region among adults aged 50 years and older. FINDINGS: In 2021, distance eREC was 79·1% (95% CI 72·4-85·0) in the high-income super region; 62·1% (54·7-68·8) in north Africa and Middle East; 49·5% (45·0-54·0) in central Europe, eastern Europe, and central Asia; 40·0% (31·7-48·2) in southeast Asia, east Asia, and Oceania; 34·5% (29·4-40·0) in Latin America and the Caribbean; 9·0% (6·5-12·0) in south Asia; and 5·7% (3·1-9·0) in sub-Saharan Africa. eREC was higher in men and reduced with increasing age. Global distance eREC increased from 2000 to 2021 by 19·0%. Global near vision eREC for 2021 was 20·5% (95% CI 17·8-24·4). INTERPRETATION: Over the past 20 years, distance eREC has increased in each super region yet the WHO target will require substantial improvements in quantity and quality of refractive services in particular for near vision impairment. FUNDING: WHO, Sightsavers, The Fred Hollows Foundation, Fondation Thea, Brien Holden Vision Institute, Lions Clubs International Foundation.

Scalable Bayesian inference for self-excitatory stochastic processes applied to big American gunfire data.

The Hawkes process and its extensions effectively model self-excitatory phenomena including earthquakes, viral pandemics, financial transactions, neural spike trains and the spread of memes through social networks. The usefulness of these stochastic process models within a host of economic sectors and scientific disciplines is undercut by the processes' computational burden: complexity of likelihood evaluations grows quadratically in the number of observations for both the temporal and spatiotemporal Hawkes processes. We show that, with care, one may parallelize these calculations using both central and graphics processing unit implementations to achieve over 100-fold speedups over single-core processing. Using a simple adaptive Metropolis-Hastings scheme, we apply our high-performance computing framework to a Bayesian analysis of big gunshot data generated in Washington D.C. between the years of 2006 and 2019, thereby extending a past analysis of the same data from under 10,000 to over 85,000 observations. To encourage widespread use, we provide hpHawkes, an open-source R package, and discuss high-level implementation and program design for leveraging aspects of computational hardware that become necessary in a big data setting.

Prevalence and causes of vision loss in sub-Saharan Africa in 2015: magnitude, temporal trends and projections.

BACKGROUND: This study aimed to assess the prevalence and causes of vision loss in sub-Saharan Africa (SSA) in 2015, compared with prior years, and to estimate expected values for 2020. METHODS: A systematic review and meta-analysis assessed the prevalence of blindness (presenting distance visual acuity <3/60 in the better eye), moderate and severe vision impairment (MSVI; presenting distance visual acuity <6/18 but ≥3/60) and mild vision impairment (MVI; presenting distance visual acuity <6/12 and ≥6/18), and also near vision impairment (

Prevalence and causes of vision loss in East Asia in 2015: magnitude, temporal trends and projections.

BACKGROUND: To determine the prevalence and causes of blindness and vision impairment (VI) in East Asia in 2015 and to forecast the trend to 2020. METHODS: Through a systematic literature review and meta-analysis, we estimated prevalence of blindness (presenting visual acuity <3/60 in the better eye), moderate-to-severe vision impairment (MSVI; 3/60≤presenting visual acuity <6/18), mild vision impairment (mild VI: 6/18≤presenting visual acuity <6/12) and uncorrected presbyopia for 1990, 2010, 2015 and 2020. A total of 44 population-based studies were included. RESULTS: In 2015, age-standardised prevalence of blindness, MSVI, mild VI and uncorrected presbyopia was 0.37% (80% uncertainty interval (UI) 0.12%-0.68%), 3.06% (80% UI 1.35%-5.16%) and 2.65% (80% UI 0.92%-4.91%), 32.91% (80% UI 18.72%-48.47%), respectively, in East Asia. Cataract was the leading cause of blindness (43.6%), followed by uncorrected refractive error (12.9%), glaucoma, age-related macular degeneration, corneal diseases, trachoma and diabetic retinopathy (DR). The leading cause for MSVI was uncorrected refractive error, followed by cataract, age-related macular degeneration, glaucoma, corneal disease, trachoma and DR. The burden of VI due to uncorrected refractive error, cataracts, glaucoma and DR has continued to rise over the decades reported. CONCLUSIONS: Addressing the public healthcare barriers for cataract and uncorrected refractive error can help eliminate almost 57% of all blindness cases in this region. Therefore, public healthcare efforts should be focused on effective screening and effective patient education, with access to high-quality healthcare.

VARIABLE PRIORITIZATION IN NONLINEAR BLACK BOX METHODS: A GENETIC ASSOCIATION CASE STUDY1.

The central aim in this paper is to address variable selection questions in nonlinear and nonparametric regression. Motivated by statistical genetics, where nonlinear interactions are of particular interest, we introduce a novel and interpretable way to summarize the relative importance of predictor variables. Methodologically, we develop the "RelATive cEntrality" (RATE) measure to prioritize candidate genetic variants that are not just marginally important, but whose associations also stem from significant covarying relationships with other variants in the data. We illustrate RATE through Bayesian Gaussian process regression, but the methodological innovations apply to other "black box" methods. It is known that nonlinear models often exhibit greater predictive accuracy than linear models, particularly for phenotypes generated by complex genetic architectures. With detailed simulations and two real data association mapping studies, we show that applying RATE enables an explanation for this improved performance.

Prevalence and causes of vision loss in Latin America and the Caribbean in 2015: magnitude, temporal trends and projections.

OBJECTIVE: To estimate the prevalence and causes of blindness and vision impairment for distance and near in Latin America and the Caribbean (LAC) in 2015 and to forecast trends to 2020. METHODS: A meta-analysis from a global systematic review of 283 cross-sectional, population-representative studies from published and unpublished sources from 1980 to 2014 in the Global Vision Database included 17 published and 6 unpublished studies from LAC. RESULTS: In 2015, across LAC, age-standardised prevalence was 0.38% in all ages and 1.56% in those over age 50 for blindness; 2.06% in all ages and 7.86% in those over age 50 for moderate and severe vision impairment (MSVI); 1.89% in all ages and 6.93% in those over age 50 for mild vision impairment and 39.59% in all ages and 45.27% in those over 50 for near vision impairment (NVI). In 2015, 117.86 million persons were vision impaired; of those 2.34 million blind, 12.46 million with MSVI, 11.34 million mildly impaired and 91.72 million had NVI. Cataract is the most common cause of blindness. Undercorrected refractive-error is the most common cause of vision impairment. CONCLUSIONS: These prevalence estimates indicate that one in five persons across LAC had some degree of vision loss in 2015. We predict that from 2015 to 2020, the absolute numbers of persons with vision loss will increase by 12% to 132.33 million, while the all-age age-standardised prevalence will decrease for blindness by 15% and for other distance vision impairment by 8%. All countries need epidemiologic research to establish accurate national estimates and trends. Universal eye health services must be included in universal health coverage reforms to address disparities, fragmentation and segmentation of healthcare.

Prevalence and causes of vision loss in North Africa and Middle East in 2015: magnitude, temporal trends and projections.

BACKGROUND: To assess the prevalence and causes of vision impairment in North Africa and the Middle East (NAME) from 1990 to 2015 and to forecast projections for 2020. METHODS: Based on a systematic review of medical literature, the prevalence of blindness (presenting visual acuity (PVA) <3/60 in the better eye), moderate and severe vision impairment (MSVI; PVA <6/18 but ≥3/60) and mild vision impairment (PVA <6/12 but ≥6/18) was estimated for 2015 and 2020. RESULTS: The age-standardised prevalence of blindness and MSVI for all ages and genders decreased from 1990 to 2015, from 1.72 (0.53-3.13) to 0.95% (0.32%-1.71%), and from 6.66 (3.09-10.69) to 4.62% (2.21%-7.33%), respectively, with slightly higher figures for women than men. Cataract was the most common cause of blindness in 1990 and 2015, followed by uncorrected refractive error. Uncorrected refractive error was the leading cause of MSVI in the NAME region in 1990 and 2015, followed by cataract. A reduction in the proportions of blindness and MSVI due to cataract, corneal opacity and trachoma is predicted by 2020. Conversely, an increase in the proportion of blindness attributable to uncorrected refractive error, glaucoma, age-related macular degeneration and diabetic retinopathy is expected. CONCLUSIONS: In 2015 cataract and uncorrected refractive error were the major causes of vision loss in the NAME region. Proportions of vision impairment from cataract, corneal opacity and trachoma are expected to decrease by 2020, and those from uncorrected refractive error, glaucoma, diabetic retinopathy and age-related macular degeneration are predicted to increase by 2020.

Prevalence and causes of vision loss in South-east Asia and Oceania in 2015: magnitude, temporal trends and projections.

BACKGROUND: To assess prevalence and causes of vision impairment in South-east Asia and Oceania regions from 1990 to 2015 and to forecast the figures for 2020. METHODS: Based on a systematic review of medical literature, prevalence of blindness (presenting visual acuity (PVA) <3/60 in the better eye), moderate and severe vision impairment (MSVI; PVA <6/18 but ≥3/60), mild vision impairment (PVA <6/12 but ≥6/18) and near vision impairment (>N5 or N8 in the presence of normal vision) were estimated for 1990, 2010, 2015 and 2020. RESULTS: The age-standardised prevalence of blindness for all ages and both genders was higher in the Oceania region but lower for MSVI when comparing the subregions. The prevalence of near vision impairment in people≥50 years was 41% (uncertainty interval (UI) 18.8 to 65.9). Comparison of the data for 2015 with 2020 predicts a small increase in the numbers of people affected by blindness, MSVI and mild VI in both subregions. The numbers predicted for near VI in South-east Asia are from 90.68 million in 2015 to 102.88 million in 2020. The main causes of blindness and MSVI in both subregions in 2015 were cataract, uncorrected refractive error, glaucoma, corneal disease and age-related macular degeneration. There was no trachoma in Oceania from 1990 and decreasing prevalence in South-east Asia with elimination predicted by 2020. CONCLUSIONS: In both regions, the main challenges for eye care come from cataract which remains the main cause of blindness with uncorrected refractive error the main cause of MSVI. The trend between 1990 and 2015 is for a lower prevalence of blindness and MSVI in both regions.

Prevalence and causes of blindness and vision impairment: magnitude, temporal trends and projections in South and Central Asia.

BACKGROUND: To assess prevalence and causes of vision loss in Central and South Asia. METHODS: A systematic review of medical literature assessed the prevalence of blindness (presenting visual acuity<3/60 in the better eye), moderate and severe vision impairment (MSVI; presenting visual acuity <6/18 but ≥3/60) and mild vision impairment (MVI; presenting visual acuity <6/12 and ≥6/18) in Central and South Asia for 1990, 2010, 2015 and 2020. RESULTS: In Central and South Asia combined, age-standardised prevalences of blindness, MSVI and MVI in 2015 were for men and women aged 50+years, 3.72% (80% uncertainty interval (UI): 1.39-6.75) and 4.00% (80% UI: 1.41-7.39), 16.33% (80% UI: 8.55-25.47) and 17.65% (80% UI: 9.00-27.62), 11.70% (80% UI: 4.70-20.32) and 12.25% (80% UI:4.86-21.30), respectively, with a significant decrease in the study period for both gender. In South Asia in 2015, 11.76 million individuals (32.65% of the global blindness figure) were blind and 61.19 million individuals (28.3% of the global total) had MSVI. From 1990 to 2015, cataract (accounting for 36.58% of all cases with blindness in 2015) was the most common cause of blindness, followed by undercorrected refractive error (36.43%), glaucoma (5.81%), age-related macular degeneration (2.44%), corneal diseases (2.43%), diabetic retinopathy (0.16%) and trachoma (0.04%). For MSVI in South Asia 2015, most common causes were undercorrected refractive error (accounting for 66.39% of all cases with MSVI), followed by cataract (23.62%), age-related macular degeneration (1.31%) and glaucoma (1.09%). CONCLUSIONS: One-third of the global blind resided in South Asia in 2015, although the age-standardised prevalence of blindness and MSVI decreased significantly between 1990 and 2015.

Prevalence and causes of vision loss in high-income countries and in Eastern and Central Europe in 2015: magnitude, temporal trends and projections.

BACKGROUND: Within a surveillance of the prevalence and causes of vision impairment in high-income regions and Central/Eastern Europe, we update figures through 2015 and forecast expected values in 2020. METHODS: Based on a systematic review of medical literature, prevalence of blindness, moderate and severe vision impairment (MSVI), mild vision impairment and presbyopia was estimated for 1990, 2010, 2015, and 2020. RESULTS: Age-standardised prevalence of blindness and MSVI for all ages decreased from 1990 to 2015 from 0.26% (0.10-0.46) to 0.15% (0.06-0.26) and from 1.74% (0.76-2.94) to 1.27% (0.55-2.17), respectively. In 2015, the number of individuals affected by blindness, MSVI and mild vision impairment ranged from 70 000, 630 000 and 610 000, respectively, in Australasia to 980 000, 7.46 million and 7.25 million, respectively, in North America and 1.16 million, 9.61 million and 9.47 million, respectively, in Western Europe. In 2015, cataract was the most common cause for blindness, followed by age-related macular degeneration (AMD), glaucoma, uncorrected refractive error, diabetic retinopathy and cornea-related disorders, with declining burden from cataract and AMD over time. Uncorrected refractive error was the leading cause of MSVI. CONCLUSIONS: While continuing to advance control of cataract and AMD as the leading causes of blindness remains a high priority, overcoming barriers to uptake of refractive error services would address approximately half of the MSVI burden. New data on burden of presbyopia identify this entity as an important public health problem in this population. Additional research on better treatments, better implementation with existing tools and ongoing surveillance of the problem is needed.

Improved prediction accuracy for disease risk mapping using Gaussian process stacked generalization.

Maps of infectious disease-charting spatial variations in the force of infection, degree of endemicity and the burden on human health-provide an essential evidence base to support planning towards global health targets. Contemporary disease mapping efforts have embraced statistical modelling approaches to properly acknowledge uncertainties in both the available measurements and their spatial interpolation. The most common such approach is Gaussian process regression, a mathematical framework composed of two components: a mean function harnessing the predictive power of multiple independent variables, and a covariance function yielding spatio-temporal shrinkage against residual variation from the mean. Though many techniques have been developed to improve the flexibility and fitting of the covariance function, models for the mean function have typically been restricted to simple linear terms. For infectious diseases, known to be driven by complex interactions between environmental and socio-economic factors, improved modelling of the mean function can greatly boost predictive power. Here, we present an ensemble approach based on stacked generalization that allows for multiple nonlinear algorithmic mean functions to be jointly embedded within the Gaussian process framework. We apply this method to mapping Plasmodium falciparum prevalence data in sub-Saharan Africa and show that the generalized ensemble approach markedly outperforms any individual method.

Magnitude, temporal trends, and projections of the global prevalence of blindness and distance and near vision impairment: a systematic review and meta-analysis.

BACKGROUND: Global and regional prevalence estimates for blindness and vision impairment are important for the development of public health policies. We aimed to provide global estimates, trends, and projections of global blindness and vision impairment. METHODS: We did a systematic review and meta-analysis of population-based datasets relevant to global vision impairment and blindness that were published between 1980 and 2015. We fitted hierarchical models to estimate the prevalence (by age, country, and sex), in 2015, of mild visual impairment (presenting visual acuity worse than 6/12 to 6/18 inclusive), moderate to severe visual impairment (presenting visual acuity worse than 6/18 to 3/60 inclusive), blindness (presenting visual acuity worse than 3/60), and functional presbyopia (defined as presenting near vision worse than N6 or N8 at 40 cm when best-corrected distance visual acuity was better than 6/12). FINDINGS: Globally, of the 7·33 billion people alive in 2015, an estimated 36·0 million (80% uncertainty interval [UI] 12·9-65·4) were blind (crude prevalence 0·48%; 80% UI 0·17-0·87; 56% female), 216·6 million (80% UI 98·5-359·1) people had moderate to severe visual impairment (2·95%, 80% UI 1·34-4·89; 55% female), and 188·5 million (80% UI 64·5-350·2) had mild visual impairment (2·57%, 80% UI 0·88-4·77; 54% female). Functional presbyopia affected an estimated 1094·7 million (80% UI 581·1-1686·5) people aged 35 years and older, with 666·7 million (80% UI 364·9-997·6) being aged 50 years or older. The estimated number of blind people increased by 17·6%, from 30·6 million (80% UI 9·9-57·3) in 1990 to 36·0 million (80% UI 12·9-65·4) in 2015. This change was attributable to three factors, namely an increase because of population growth (38·4%), population ageing after accounting for population growth (34·6%), and reduction in age-specific prevalence (-36·7%). The number of people with moderate and severe visual impairment also increased, from 159·9 million (80% UI 68·3-270·0) in 1990 to 216·6 million (80% UI 98·5-359·1) in 2015. INTERPRETATION: There is an ongoing reduction in the age-standardised prevalence of blindness and visual impairment, yet the growth and ageing of the world's population is causing a substantial increase in number of people affected. These observations, plus a very large contribution from uncorrected presbyopia, highlight the need to scale up vision impairment alleviation efforts at all levels. FUNDING: Brien Holden Vision Institute.