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OBJECTIVES: To determine whether implementation of comprehensive in-school eyecare results in measurable benefits for children and young people in terms of visual status, classroom behaviours and how well their visual needs are met. DESIGN: School-based observational study. PARTICIPANTS & METHODS: 200 pupils [mean age 10 years 9 months, 70% male, majority moderate (40%) or severe (35%) learning difficulty] of a special education school in the UK. A sector-agreed in-school eyecare framework including full eye examination and cycloplegic refraction, dispensing of spectacles (as appropriate) and written reporting of outcomes to parents/teachers was applied. Classroom behaviours were observed and recorded prior to, and after, the in-school eyecare. Surveys were employed to obtain visual histories from parents/teachers. School records and statutory documents were reviewed for diagnostic and learning disability classifications. Visual function and ocular health were profiled at baseline and significant visual deficits identified. Where such deficits were previously unrecognised, untreated or not compensated for (e.g. correction of refractive error, enlargement of educational material) they were recorded as 'unmet visual need'. At follow-up, 2-5 months after initial (baseline) measures, eye examinations, parent/teacher surveys and behaviour observations were repeated. Follow-up measures were used to determine if measurable improvements were evident in visual function, ocular health, the level of unmet need and classroom behaviour following implementation of in-school eyecare. RESULTS: 199 participants completed baseline and follow-up measures. 122 (61%) participants presented with at least one significant visual or ocular health deficit and 90 (45%) participants had at least one unmet visual need. Younger pupils and those with no previous history of eyecare were more likely to demonstrate unmet visual needs at baseline (OR 1.12 95% CI 1.03 to 1.21) p = 0.012; (OR 4.44 95% CI 1.38 to 14.29 p = 0.007 respectively). On follow-up, the number of pupils with unmet visual needs dropped significantly to 36 (18%) (McNemar's test p<0.001). Visual and behavioural metrics of participants without significant visual deficits or whose visual needs were adequately addressed at baseline remained relatively unchanged between baseline and follow-up (Wilcoxon signed rank p>0.05). Where significant refractive deficits were corrected at follow-up, near visual acuity improved significantly (Wilcoxon signed rank p = 0.013), however, poor spectacle compliance was a persistent cause of unmet visual need. Off-task behaviour reduced significantly after actions to address unmet visual needs were communicated to parents and teachers (Wilcoxon signed rank p = 0.035). CONCLUSIONS: The present study demonstrates for the first time measurable visual and behaviour benefits to children in special education settings when they receive comprehensive in-school eye examinations, on-site spectacle dispensing and jargon-free reporting of outcomes to teachers and parents.
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Conducta Infantil , Educación Especial , Servicios de Salud Escolar , Selección Visual/métodos , Visión Ocular , Niño , Femenino , Humanos , Discapacidades para el Aprendizaje/complicaciones , Discapacidades para el Aprendizaje/psicología , Masculino , Trastornos de la Visión/complicaciones , Trastornos de la Visión/diagnóstico , Trastornos de la Visión/terapiaRESUMEN
[This corrects the article DOI: 10.1371/journal.pone.0220480.].
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An urgent need for rapid sensors to detect contamination of food grains by toxigenic fungi such as Aspergillus flavus prompted research and development of Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) as a highly sensitive probe for fungi growing on the surfaces of individual corn kernels. However, the photoacoustic technique has limited potential for screening bulk corn because currently available photoacoustic detectors can accommodate only a single intact kernel at a time. Transient infrared spectroscopy (TIRS), on the other hand, is a promising new technique that can acquire analytically useful infrared spectra from a moving mass of solid materials. Therefore, the potential of TIRS for on-line, noncontact detection of A. flavus contamination in a moving bed of corn kernels was explored. Early test results based on visual inspection of TIRS spectral differences predict an 85% or 95% success rate in distinguishing healthy corn from grain infected with A. flavus. Four unique infrared spectral features which identified infected corn in FTIR-PAS were also found to be diagnostic in TIRS. Although the technology is still in its infancy, the preliminary results indicate that TIRS is a potentially effective screening method for bulk quantities of corn grain.
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Aflatoxinas/aislamiento & purificación , Aspergillus flavus/aislamiento & purificación , Microbiología de Alimentos , Zea mays/microbiología , Humanos , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
PURPOSE: Limited data exist detailing the normal range of intraocular pressure (IOP) for healthy school age children. This study aims to describe the mean and normal range of IOP measurements that may be expected using the Icare rebound tonometer and to examine associations between visual function measures and IOP. METHODS: Six measurements of IOP from each eye were obtained from 211 normal children aged 6-15 years (79 females and 132 males) using the Icare tonometer. Other measures of visual function obtained included: visual acuity, non-cycloplegic retinoscopy, amplitude of accommodation, accommodative facility, and accommodative response. RESULTS: Statistical analysis (Mann-Whitney U test) demonstrated that the male subjects were more likely to have higher IOP measurements than the female subjects (mean IOP males 15.02 mm Hg (SD 2.19), mean IOP females 14.44 (SD 2.01) P=0.041). Analysis (Spearman's rho) showed a statistically significant association between age and IOP (right eye) in males (P<0.001) but no association for females (P=0.459). Using Spearman's rank analysis, statistically significant associations were found between IOP and amplitude of accommodation in males, for the whole data set (P=0.09) and for data up to age 11 (P<0.001). For females no statistically significant association was found for the whole data set (P=0.253) or for data up to age 11 (P=0.08). IOP was not significantly associated with visual acuity, refractive error, accommodative facility, or accommodative response. CONCLUSION: This study provides useful normative IOP data using the Icare tonometer for a European cohort of school age children.
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Envejecimiento/fisiología , Presión Intraocular/fisiología , Acomodación Ocular/fisiología , Adolescente , Austria , Niño , Femenino , Humanos , Masculino , Valores de Referencia , Tonometría Ocular , Agudeza Visual/fisiologíaRESUMEN
AIMS: To describe the prevalence of refractive error (myopia and hyperopia) and visual impairment in a representative sample of white school children. METHODS: The Northern Ireland Childhood Errors of Refraction study, a population-based cross-sectional study, examined 661 white 12-13-year-old and 392 white 6-7-year-old children between 2006 and 2008. Procedures included assessment of monocular logarithm of the minimum angle of resolution (logMAR), visual acuity (unaided and presenting) and binocular open-field cycloplegic (1% cyclopentolate) autorefraction. Myopia was defined as -0.50DS or more myopic spherical equivalent refraction (SER) in either eye, hyperopia as > or =+2.00DS SER in either eye if not previously classified as myopic. Visual impairment was defined as >0.30 logMAR units (equivalent to 6/12). RESULTS: Levels of myopia were 2.8% (95% CI 1.3% to 4.3%) in younger and 17.7% (95% CI 13.2% to 22.2%) in older children: corresponding levels of hyperopia were 26% (95% CI 20% to 33%) and 14.7% (95% CI 9.9% to 19.4%). The prevalence of presenting visual impairment in the better eye was 3.6% in 12-13-year-old children compared with 1.5% in 6-7-year-old children. Almost one in four children fails to bring their spectacles to school. CONCLUSIONS: This study is the first to provide robust population-based data on the prevalence of refractive error and visual impairment in Northern Irish school children. Strategies to improve compliance with spectacle wear are required.
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Hiperopía/epidemiología , Miopía/epidemiología , Trastornos de la Visión/epidemiología , Niño , Anteojos/estadística & datos numéricos , Femenino , Humanos , Hiperopía/fisiopatología , Masculino , Miopía/fisiopatología , Irlanda del Norte/epidemiología , Cooperación del Paciente/estadística & datos numéricos , Prevalencia , Factores Socioeconómicos , Trastornos de la Visión/fisiopatología , Agudeza Visual , Población BlancaRESUMEN
BACKGROUND: There is a paucity of data describing the prevalence of childhood refractive error in the United Kingdom. The Northern Ireland Childhood Errors of Refraction study, along with its sister study the Aston Eye Study, are the first population-based surveys of children using both random cluster sampling and cycloplegic autorefraction to quantify levels of refractive error in the United Kingdom. METHODS: Children aged 6-7 years and 12-13 years were recruited from a stratified random sample of primary and post-primary schools, representative of the population of Northern Ireland as a whole. Measurements included assessment of visual acuity, oculomotor balance, ocular biometry and cycloplegic binocular open-field autorefraction. Questionnaires were used to identify putative risk factors for refractive error. RESULTS: 399 (57%) of 6-7 years and 669 (60%) of 12-13 years participated. School participation rates did not vary statistically significantly with the size of the school, whether the school is urban or rural, or whether it is in a deprived/non-deprived area. The gender balance, ethnicity and type of schooling of participants are reflective of the Northern Ireland population. CONCLUSIONS: The study design, sample size and methodology will ensure accurate measures of the prevalence of refractive errors in the target population and will facilitate comparisons with other population-based refractive data.
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Errores de Refracción/epidemiología , Adolescente , Niño , Métodos Epidemiológicos , Femenino , Humanos , Masculino , Irlanda del Norte/epidemiología , Examen Físico/métodos , Proyectos de Investigación , Pruebas de VisiónRESUMEN
Dynamic retinoscopy (DR) is an objective technique that has been used successfully to examine accommodative function of non-communicative patients. However, there are few studies examining its repeatability and validity. This paper addresses the repeatability and validity of a form of DR (a modified Nott technique), by comparing results to the Shin-Nippon SRW-5000 Autorefractor whose validity and repeatability have previously been demonstrated. Accommodative responses of 41 subjects (aged 6-43 years) were assessed using DR and the Shin-Nippon SRW-5000 Autorefractor. Three different target demands were used (10, 6 and 4 D). DR was shown to be repeatable for all target demands (paired t-test, p > 0.05). The results demonstrated good agreement between the autorefractor and DR. The results of the present study suggest that DR is a repeatable and valid objective technique for assessing accommodative function.
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Acomodación Ocular , Oftalmoscopios , Oftalmoscopía/métodos , Retina/fisiología , Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Errores de Refracción , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
A discussion of the photoacoustic spectroscopy of condensed matter is presented with emphasis on the role of the sample and the sample cell in the photoacoustic signal waveform. The spectrometer and sample cell are described, and an experimental evaluation of the system performance is given. Data on various samples are reported, and sample geometry, signal saturation, and scattered light effects are analyzed. The relationship between photoacoustic spectra and absorption and reflection spectra is developed.
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Transient infrared transmission spectroscopy is a new method that can acquire analytically useful transmission spectra from moving, optically thick solids. No sample preparation is required. The spectra are of sufficient quality for accurate quantitative compositional analysis. The method works by the creation of a thin, short-lived, chilled layer at the sample surface. Blackbody-like thermal emission from the bulk of the sample is selectively absorbed as it passes through the chilled layer, so the transmission spectrum of the layer is superimposed on the observed thermal emission. Spectra of polycarbonate, beeswax, and copolymers of methyl and butyl methacrylate are presented. Compositional analysis of the methacrylate copolymers with a standard error of prediction of only 0.87 mol % is demonstrated.
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Técnicas de Química Analítica/métodos , Espectrofotometría Infrarroja/métodosRESUMEN
FT-IR/PAS (Fourier transform infrared/photoacoustic spectroscopy) was used to evaluate the secondary structure of proteins. Four well-studied proteins, concanavalin A, hemoglobin, lysozyme, and trypsin, which have different distributions of secondary structures, were used for assignments of the infrared bands and evaluating the accuracy of FT-IR/PAS methods. Secondary structure contents estimated from FT-IR/PAS and other physical methods (e.g., X-ray diffraction, CD, and traditional FT-IR) show good agreement. In addition, the secondary structure can be evaluated with as little as 0.5 micrograms of protein (concanavalin A), suggesting that FT-IR/PAS is a sensitive and useful technique that could be applied to studies of the folding of recombinant and mutant proteins where only small amounts of material are available. Recombinant phosphorylase kinase gamma 1-300 subunit expressed in Escherichia coli was found in the inclusion bodies. We found that renatured phosphorylase kinase gamma 1-300 subunit has two kinase forms: one has a 10-fold higher activity than the other one. Both fractions, however, are the same as judged from sodium dodecylsulfate-polyacrylamide gel electrophoresis. Differences in conformation were demonstrated by using the FT-IR/PAS method, which showed that the low-activity form has more beta-sheet structure than the form with high activity. Analysis of these kinase forms by CD confirms the interpretation made by the FT-IR/PAS method.
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Estructura Secundaria de Proteína , Proteínas Recombinantes/química , Sensibilidad y Especificidad , Espectroscopía Infrarroja por Transformada de Fourier/instrumentaciónRESUMEN
A common product was identified by HPLC from the heating of, alpha and beta isomers of, aspartyl glycine in the dry state. Fast atom-bombardment (FAB) mass spectrometry and Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) showed that the product is a cyclic imide. Cyclic imide formation also was shown to occur with the tripeptides Gly-Asp-Gly and Gly-Asn-Gly. The cyclization of aspartyl peptides depends upon protonation of the beta-carboxyl group and can be promoted by acidification or by heating the NH4+ salt in the dry state.