Trends in prevalence of blindness and distance and near vision impairment over 30 years: an analysis for the Global Burden of Disease Study

Published Online December 1, 2020Background: To contribute to the WHO initiative, VISION 2020: The Right to Sight, an assessment of global vision impairment in 2020 and temporal change is needed. We aimed to extensively update estimates of global vision loss burden, presenting estimates for 2020, temporal change over three decades between 1990–2020, and forecasts for 2050. Methods: We did a systematic review and meta-analysis of population-based surveys of eye disease from January, 1980, to October, 2018. Only studies with samples representative of the population and with clearly defined visual acuity testing protocols were included. We fitted hierarchical models to estimate 2020 prevalence (with 95% uncertainty intervals [UIs]) of mild vision impairment (presenting visual acuity ≥6/18 and <6/12), moderate and severe vision impairment (<6/18 to 3/60), and blindness (<3/60 or less than 10° visual field around central fixation); and vision impairment from uncorrected presbyopia (presenting near vision <N6 or <N8 at 40 cm where best-corrected distance visual acuity is ≥6/12). We forecast estimates of vision loss up to 2050. Findings: In 2020, an estimated 43·3 million (95% UI 37·6–48·4) people were blind, of whom 23·9 million (55%; 20·8–26·8) were estimated to be female. We estimated 295 million (267–325) people to have moderate and severe vision impairment, of whom 163 million (55%; 147–179) were female; 258 million (233–285) to have mild vision impairment, of whom 142 million (55%; 128–157) were female; and 510 million (371–667) to have visual impairment from uncorrected presbyopia, of whom 280 million (55%; 205–365) were female. Globally, between 1990 and 2020, among adults aged 50 years or older, age-standardised prevalence of blindness decreased by 28·5% (–29·4 to –27·7) and prevalence of mild vision impairment decreased slightly (–0·3%, –0·8 to –0·2), whereas prevalence of moderate and severe vision impairment increased slightly (2·5%, 1·9 to 3·2; insufficient data were available to calculate this statistic for vision impairment from uncorrected presbyopia). In this period, the number of people who were blind increased by 50·6% (47·8 to 53·4) and the number with moderate and severe vision impairment increased by 91·7% (87·6 to 95·8). By 2050, we predict 61·0 million (52·9 to 69·3) people will be blind, 474 million (428 to 518) will have moderate and severe vision impairment, 360 million (322 to 400) will have mild vision impairment, and 866 million (629 to 1150) will have uncorrected presbyopia. Interpretation: Age-adjusted prevalence of blindness has reduced over the past three decades, yet due to population growth, progress is not keeping pace with needs. We face enormous challenges in avoiding vision impairment as the global population grows and ages.Rupert R A Bourne ... Robert James Casson ... et al. (GBD 2019 Blindness and Vision Impairment Collaborators on behalf of the Vision Loss Expert Group of the Global Burden of Disease Study

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

Preoperative mitomycin, ifosfamide, and cisplatin followed by esophagectomy in squamous cell carcinoma of the esophagus: pathologic complete response induced by chemotherapy leads to long-term survival.

PURPOSE: Squamous cell carcinoma of the esophagus remains an aggressive disease with a poor prognosis, even after curative-intent surgery. This article analyzes the impact of preoperative chemotherapy with mitomycin, ifosfamide, and cisplatin (MIC) on a cohort of 68 patients. PATIENTS AND METHODS: From 1988 to 1994, 68 patients with potentially operable squamous cell carcinoma of the esophagus were entered onto two phase II trials of neoadjuvant chemotherapy with mitomycin 6 mg/m2, ifosfamide 3 g/m2, and cisplatin 50 mg/m2 and received between two and four cycles of treatment at 3-weekly intervals. Two patients were removed from the analysis when they were found to have malignancy other than squamous cell carcinoma of the esophagus. RESULTS: Forty (61%) of 66 patients had a radiologic response to chemotherapy (18 complete responses and 22 partial responses), and 52 (79%) of 66 patients went on to have the primary tumor resected. There were nine pathologic complete responders, seven of whom remain fit and well after at least 60 months of follow-up. The overall median survival was 12.4 months (95% confidence interval, 9.6 to 18.8 months). The complete response and node-negative patients survived significantly longer than those in other categories (log-rank chi2 = 18.8; P <.001): on average 13 months longer than the node-positive or nonresected category (22.0 v 9.4 months). The toxicity of the regimen was low. CONCLUSION: MIC is an easily administered, well-tolerated, and efficacious regimen as neoadjuvant therapy for patients with squamous cell carcinoma of the esophagus. These results warrant further investigation

Enterprise education: the need for differentation

There has been a proliferation of enterprise courses in the UK in the last ten years. The aims, curricula and target groups for these courses are diverse. Efforts have been made to identify the generic characteristics of enterprise education (See Johnson, 1988). However, the interpretation of the concept enterprise is varied and reflects diverse teaching methods and educational objectives which suggests that it may be time to abandon the general label of enterprise education. This paper explores the characteristics of enterprise education and argues for a distinction to be made between the occupationally focused small business courses and more ‘progressive’ forms of enterprise education which may be more correctly called competency education initiatives

The magnitude and breadth of hepatitis C virus-specific CD8+ T cells depend on absolute CD4+ T-cell count in individuals coinfected with HIV-1

CD8+ T-cell responses are an essential antiviral host defense in persistent viral infections, and their sustained effectiveness is thought to be critically dependent on CD4+ T-helper cells. To determine the relationship between HIV-1–induced CD4+ T-cell depletion and hepatitis C virus (HCV)–specific CD8+ T-cell responses during viral persistence, we studied 103 persons positive for HCV, 74 coinfected with HIV-1. CD8+ T-cell responses to the entire HCV polyprotein were determined by using an interferon-γ enzyme-linked immunospot (ELISpot) assay. Although HIV-1 infection by itself was not associated with a diminished HCV-specific response, HIV-1–associated CD4+ depletion was associated with significantly lower HCV-specific CD8+ T cells (R = 0.48, P < .0001). In contrast, declining CD4+ counts over the same range were not associated with diminished Epstein-Barr virus (EBV)– (R = 0.19, P = .31) or HIV-1–specific (R = –0.13, P = .60) CD8+ T-cell responses in persons infected with all viruses. These data indicate that frequencies of circulating HCV-specific CD8+ T-cell responses are sensitive to absolute CD4+ T-cell counts and provide a possible explanation for the accelerated HCV disease course in persons coinfected with HIV-1 and HCV