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

Global causes of blindness and distance vision impairment 1990–2020: a systematic review and meta-analysis

Background: Contemporary data on causes of vision impairment and blindness form an important basis for recommendations in public health policies. Refreshment of the Global Vision Database with recently published data sources permitted modeling of cause of vision loss data from 1990 to 2015, further disaggregation by cause, and forecasts to 2020. Methods: Published and unpublished population-based data on the causes of vision impairment and blindness from 1980 to 2015 were systematically analysed. A series of regression models were fit to estimate the proportion of moderate and severe vision impairment (MSVI; defined as presenting visual acuity <6/18 but ≥3/60 in the better eye) and blindness (presenting visual acuity <3/60 in the better eye) by cause by age, region, and year. Findings: Among the projected global population with MSVI (216.6 million; 80% uncertainty intervals [UI] 98.5-359.1), in 2015 the leading causes thereof are uncorrected refractive error (116.3 million; UI 49.4-202.1), cataract (52.6 million; UI 18.2-109.6), age-related macular degeneration (AMD; 8.4 million; UI 0.9-29.5), glaucoma (4.0 million; UI 0.6-13.3) and diabetic retinopathy (2.6 million; UI 0.2-9.9). In 2015, the leading global causes of blindness were cataract (12.6 million; UI 3.4-28.7) followed by uncorrected refractive error (7.4 million; UI 2.4-14.8) and glaucoma (2.9 million; UI 0.4-9.9), while by 2020, these numbers affected are anticipated to rise to 13.4 million, 8.0 million and 3.2 million, respectively. Cataract and uncorrected refractive error combined contributed to 55% of blindness and 77% of MSVI in adults aged 50 years and older in 2015. World regions varied markedly in the causes of blindness, with a relatively low prevalence of cataract and a relatively high prevalence of AMD as causes for vision loss in the High-income subregions. Blindness due to cataract and diabetic retinopathy was more common among women, while blindness due to glaucoma and corneal opacity was more common among men, with no gender difference related to AMD. Conclusions: The numbers of people affected by the common causes of vision loss have increased substantially as the population increases and ages. Preventable vision loss due to cataract and refractive error (reversible with surgery and spectacle correction respectively), continue to cause the majority of blindness and MSVI in adults aged 50+ years. A massive scale up of eye care provision to cope with the increasing numbers is needed if one is to address avoidable vision loss

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Alimentação nos primeiros três meses de vida dos bebês de uma coorte na cidade de Pelotas, Rio Grande do Sul Alimentación en los primeros tres meses de vida de los bebés de una coorte en la ciudad de Pelotas, Rio Grande do Sul (Brasil) Feeding during the first three months of life for infants of a cohort in Pelotas, Rio Grande do Sul, Brazil

OBJETIVO: Estudar o padrão alimentar nos primeiros três meses de vida de crianças nascidas na cidade de Pelotas (RS). MÉTODOS: Estudo de coorte prospectivo com os bebês nascidos entre setembro de 2002 e maio de 2003, na cidade de Pelotas (RS). Incluíram-se 2.741 bebês nas maternidades e uma amostra aleatória de 30% acompanhada no primeiro e terceiro meses de vida. Foram realizadas análises uni, bi e multivariada. Somente as variáveis com p<0,05 foram consideradas associadas ao desfecho de forma significante. RESULTADOS: Foram acompanhados 951 bebês no primeiro mês, dos quais 60% estavam em aleitamento materno exclusivo e 10% já estavam desmamados. As variáveis associadas ao desmame, neste período, foram: tabagismo na gravidez, escolaridade do pai inferior a quatro anos e uso de chupeta. No terceiro mês, 940 crianças foram acompanhadas: 29% haviam desmamado, 39% recebiam leite materno exclusivo e 59% utilizavam mamadeira. Tabagismo materno, escolaridade paterna e uso de chupeta, mantiveram-se associados ao desmame precoce. Houve aumento do uso de chupeta de 56 para 66% do primeiro para o terceiro mês, respectivamente. CONCLUSÕES: Comparado a estudos anteriores, evidenciou-se melhora nos índices de aleitamento materno, embora ainda inferiores aos valores ideais preconizados pela Organização Mundial de Saúde, o que ressalta a necessidade de estimulação à prática de aleitamento materno exclusivo no pré-natal e nos primeiros meses de vida.<br>OBJETIVO: Estudiar el estándar alimentar en los primeros tres meses de vida de niños nascidos en la ciudad de Pelotas (RS, Brasil). MÉTODOS: Estudio de coorte prospectivo con bebés nascidos entre septiembre de 2002 y mayo de 2003, en la ciudad de Pelotas (RS, Brasil). Se incluyó a 2.741 bebés en las maternidades y una muestra aleatoria de 30%, seguida en el primero y el tercero meses de vida. Se realizaron análisis uni, bi y multivariados, y solamente las variables con p<0,05 fueron consideradas asociadas al desfecho de modo estadísticamente significativo. RESULTADOS: Se siguió a 951 bebés el primer mes, de los que el 60% estaba en lactancia materna exclusiva y el 10% ya estaban desmamados. Las variables asociadas al destete en ese periodo fueron: tabaquismo en el embarazo, escolaridad del padre inferior a cuatro años y uso de chupete. En el tercer mes, 940 niños fueron seguidos: el 29% estaba desmamado, el 39% recibía leche materna exclusiva y el 59% usaba biberón. Tabaquismo materno, escolaridad paterna y uso de chupete se mantuvieron asociados al destete temprano. Hubo aumento del uso de chupete de 56 para 66% del primero para el tercer mes, respectivamente. CONCLUSIONES: Comparado a estudios anteriores, el presente estudio evidenció mejora en los índices de lactancia materna, aunque todavía inferiores a los valores ideales preconizados por la Organización Mundial de Salud, lo que pone de relieve la necesidad de estimulación práctica de lactancia materna exclusiva en el pre-natal y los primeros meses de vida.<br>OBJECTIVE: To study the feeding pattern in the first three months of babies born in the Pelotas city, in Sothern Brazil. METHODS: Prospective cohort study, with babies born between september 2002 and may 2003. Among 2,741 babies whose mothers were interviewed at the maternity ward, a random sample of 30% was followed up on the first and third months of age. Univariate, bivariate and multivariate analyses were applied. Variables with a p<0.05 were considered as associated. RESULTS: 951 babies were followed up on the first month, 60% were under exclusive maternal breastfeeding, and 10% were already weaned. Smoking during pregnancy, father's educational level lower than four years and the use of a pacifier were associated to weaning. On the third month, 29% had been weaned, 39% received maternal milk exclusively, and 59% were bottle fed. Smoking during pregnancy, father schooling and the use of a pacifier were associated with weaning. There was an increase in the pacifier use - from 56 to 66% between the first and the third month of life. CONCLUSIONS: When compared to previous studies, an improvement on the rates of breastfeeding was shown, though still lower than World Health Organization recommendations, which highlights the need for stimulation of exclusive breastfeeding during prenatal care and during the first months after birth