1,721,052 research outputs found
L’ipovisione: epidemioLogia, risvoLti medico- LegaLi, aspetti
No full textL’ipovisione è una realtà poco conosciuta, che, erroneamente, viene spesso assimilata alla cecità. Essa invece si caratterizza autonomamente non solo da un punto di vista medico-oftalmologico, ma altresì anche patologico e psicosociale.
L’ipovisione è una condizione di ridotta capacità visiva, tale da condizionare l’autonomia dell’individuo: può essere correttamente definita come un danno visivo non correggibile per mezzo dei comuni occhiali da vista o di lenti a contatto.
Condizioni di ipovisione giovanile sono per lo più di natura congenita, nell’adulto la patologie più frequenti che inducono una ridotta acuità visiva si riassumono più frequentemente nella degenerazione maculare senile, la retinopatia diabetica, la miopia elevata, la cataratta, la retinite pigmentosa, il glaucoma, il cheratocono e le conseguenze traumatiche.
La capacità visiva di tutti i giorni diviene un grosso handicap a casa,
sul lavoro, a scuola: influisce sulle abitudini quotidiane come la lettura,
la scrittura, l’autonomia domestica e personale, la distinzione dei volti, guardare la televisione o muoversi in maniera indipendente
Effect of refractive correction on the accuracy of frequency-doubling technology matrix
No full textPurpose: To investigate the effect of refractive correction on the reliability and accuracy of frequency-doubling technology (FDT) Matrix examinations.Methods: Forty-eight eyes of healthy people were submitted to the FDT Matrix 30/2 threshold program. They had experience in perimetry, normal eye examination, and negative history for glaucoma and/or neurological diseases. The subjects were randomized into groups A (24 subjects) and B (24 subjects). The FDT Matrix 30/2 examinations were carried out in 3 different sessions. At the first session, groups A and B underwent the examinations with their best refractive correction. In the second session, group A underwent the FDT 30/2 examination with best refractive correction and the group B without it. In the third session, the groups were matched and followed the same protocol. The perimetric and reliability indexes and the time of examination with or without correction were considered. The Student t test was used when the distribution of the data was normal, whereas Mann-Whitney when the distribution of the data was not normal. After a Bonferroni correction, a P value <0.001 was considered as statistically significant.Results: Mean deviation reduced statistically significantly when refractive correction was used (-2.65 +/- 3.71 vs. -1.41 +/- 3.51 dB; P<0.006). All the other perimetric indexes and data considered did not change significantly when the subjects did the examination with or without the refractive correction.Conclusions: The statistically significant reduction of mean deviation obtained with corrective lens showed that a better general accuracy and reliability of FDT responses was obtained with refractive correction. Pattern standard deviation constancy with or without correction confirmed that a localized defect is the first sign of visual field defect and that the absence of differences of pattern standard deviation between the 2 sessions is related to the absence of pathologic conditions in the eyes studied. Finally, as FDT Matrix is less influenced by other nonconventional perimetric techniques by refractive errors, the use of corrective lens is advisable to improve the accuracy and reliability of the results obtained and to optimize their performance
Caso clinico di un corpo estraneo corneale con diagnosi e management conservativo a lungo termine
No full textPurpose: To describe the diagnosis and
management of one case of a patient with a welltolerated
and long-standing retained intracorneal
brick foreign body.
Methods: Observational case report.
Results: A 42-years old man was admitted to our
clinic with an intracorneal brick foreign body well
demarcated in the posterior stroma of the right eye
(RE ) cornea in the correspondence of the inferior
quadrant at 6.30 o’ clock.
No signs of perforation were underlined at
slit-lamp-examination (SLE ) and fundus
biomicroscopy examination: the foreign body
stopped at 98 μ distance from corneal endothelium,
well tolerated and encapsulated, almost simulating
a sort of breach like a corneal tunnel.
Optical Coherence Tomography-Visante (Visante
1000, Carl Zeiss Meditec Inc, Dublin, CA , USA)
examination of the anterior segment of the RE
and color anterior segment photographs were
carried out to compare foreign body position and
corneal tissue reactions in the follow up visits”
Conclusion: Treatment options and classic
studies teach us that intracorneal foreign bodies
must be removed especially to avoid the danger
of the infections, but in some cases it is possible
obtain to a conservative management because
they can be well-tolerated by the eye without
sympthoms and preserving outcomes in visualacuity
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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