Near Vision Tasks and Optical Quality of the Eye

Purpose: To study the effect of near-vision reading task on optical quality of the eye when performed on a computer monitor and on printed paper, and to identify which of the two results in greater changes. Methods: Two groups of subjects performed a 30-min reading task in two different conditions: on a computer monitor and on printed paper. Ocular, corneal, and internal wavefront aberrations (Zernike coefficients up to 6th order), root-mean-square of low- and high-order aberrations, spherical equivalent, vectoral components of ocular astigmatism ( J45 and J0), and the compensation factor between internal and corneal aberrations were measured before and after the tasks. Their changes were analyzed in each group and between groups. Results: Statistically significant changes in wavefront aberrations and in root mean square of low- and high-order aberrations were observed in both groups which was significantly greater when the task was performed on printed paper. Partial loss of compensation mechanism and variation in spherical equivalent in a negative direction occurred after both reading tasks; however, it was statistically significant only with printed paper reading task. The vectoral components of ocular astigmatism did not show statistically significant changes in either groups. Conclusion: Near-vision reading tasks can change the optical quality of the eye, especially when the task is performed on printed paper

Variação das aberrações oculares com a acomodação em tempo real

Dissertação de mestrado em Optometria AvançadaA aberrometria é uma das técnicas disponíveis para a determinação da qualidade ótica do olho. Tem sido aplicada clinicamente e mostrado ser uma importante ferramenta de avaliação. As aberrações oculares variam com vários fatores, tal como a idade, diâmetro pupilar, erro refrativo e acomodação ocular. Para ter uma melhor compreensão dos mecanismos do olho humano, é importante analisar essas alterações das aberrações oculares. Neste trabalho é apresentada uma metodologia que permite variar de forma dinâmica a acomodação. Esta metodologia permite alterar o estímulo acomodativo e medir, in vivo e em tempo real, a variação das aberrações oculares. Para isso, foi montado um sistema que contém diferentes lentes de potência negativa que estimulam a acomodação, e que se encontra acoplado a um aberrómetro de Shack-Hartmann. Os dois sistemas encontram-se sincronizados permitindo determinar a cada momento, e simultaneamente, o estímulo acomodativo e a respetiva resposta em termos da variação das aberrações oculares. Para a análise dos dados obtidos, foram desenvolvidos algoritmos para calcular parâmetros acomodativos, como a resposta e atraso acomodativo, o tempo de resposta para acomodar e relaxar a acomodação. Com esta análise é possível obter uma informação detalhada do comportamento da acomodação em diferentes condições. São apresentados casos reais das aplicações desta técnica, nomeadamente em pacientes sintomáticos que não apresentaram alterações nos exames optométricos realizados habitualmente na prática clínica, mas que são detetáveis através da aplicação desta metodologia. Os resultados mostraram que o método desenvolvido é eficaz e com diversas aplicações como, por exemplo, no estudo das variações das propriedades óticas do olho como no diagnóstico e acompanhamento de disfunções acomodativas.Aberrometry is one of the techniques available for the measurement of the optical quality of the eye. It has been applied clinically and shown to be an important diagnosis and evaluation tool. The ocular aberrations are affected by several factors, such as age, pupil diameter, refractive error and ocular accommodation. To have a better and comprehensive knowledge of the human eye it is important to analyze these changes in the ocular aberrations. Here a new methodology to assess how the aberrations change with the accommodative eye is presented. This methodology permits in vivo and in real time accommodative stimulation and simultaneous acquisition of the variations of ocular aberrations. A system with several negative lenses that stimulate the ocular accommodation, coupled with a wavefront sensor by using a Shark-Hartmann sensor, was developed. These two systems are synchronized, allowing the detection of the ocular aberrations while the eye is under the influence of the accommodative stimulus. To analyze de data obtained, algorithms were developed to calculate some accommodative parameters, as the accommodative response and lag, the time of the response of the ocular accommodation and its relaxation. With such analysis it is possible to obtain detailed information about the ocular accommodation behavior under different viewing conditions. Data obtained from real observers performing the experimental procedure is presented, focusing on the applications of this technique to symptomatic patients who do not present changes or findings in the regular optometric exams in use in the optometric clinical practice, but are detected by applying this methodology. Results showed that the methodology developed is effective and with several applications, for example for studying the variations of the optical proprieties of the eye and in helping in the clinical diagnosis of patients with accommodative dysfunctions and posterior follow-up

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42·4% vs 44·2%; absolute difference -1·69 [-9·58 to 6·11] p=0·67; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5-8] vs 6 [5-8] cm H2O; p=0·0011). ICU mortality was higher in MICs than in HICs (30·5% vs 19·9%; p=0·0004; adjusted effect 16·41% [95% CI 9·52-23·52]; p<0·0001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0·80 [95% CI 0·75-0·86]; p<0·0001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status