1,720,957 research outputs found
Optical coherence tomography, frequency-doubling technology, and colour Doppler imaging in ocular hypertension
No full textPURPOSE: To study in ocular hypertension (OH) the retinal nerve fibre layer (RNFL) with optical coherence tomography (OCT) and the neuronal function with frequency-doubling technology (FDT) to assess which of the two methods was more sensitive in detecting early glaucomatous damage. Furthermore, a colour Doppler imaging (CDI) of the optic nerve was carried out to highlight any correlation with RNFL thickness and FDT abnormality. MATERIALS AND METHODS: We enrolled 28 ocular hypertensive patients who underwent OCT of the RNFL and FDT. Moreover, we performed a CDI of the ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary arteries (PCAs). RESULTS: The patients with OH following OCT revealed a significant thinning in the RNFL as compared to the control group only in the inferior quadrant: 122.250+/-14.091 vs131.750+/-10.729 mum (P<0.045). As regards FDT, there was a significant difference between the two groups only for pattern standard deviation (PSD): 3.873+/-1.488 vs1.938+/-0.704 dB (P<0.044). In OH and in the control group, CDI resistance index (RI) in the OA was 0.768+/-0.012 vs0.745+/-0.019 (P<0.022), in the CRA was 0.66+/-0.012 vs0.645+/-0.019 (P<0.032), and in PCAs was 0.673+/-0.039 vs0.622+/-0.012 (P<0.037). The OCT had a sensitivity of 83% but only in the inferior RNFL quadrant. The FDT-PSD revealed a sensitivity of 85%. CONCLUSIONS: Both FDT and OCT detect early glaucomatous damage with a slightly superior sensitivity of FDT vsOCT. The CDI measurements suggest that circulatory abnormalities may have a role in the development of OCT and FDT damage.
PMID: 16888642 [PubMed - in process
Prostaglandin Analogs and Blood-Aqueous Barrier Integrity: A Flare Cell Meter Study.
No full textTo study, with an abjective method, inflammation of the anterior segment of the glaucomatous eye after treatment with latanoprost, travoprost and bimatoprost. The flare meter analysis shows that the eyes treated with bimatoprost and travoprost have a less significantly broken blood-aqueous barrier and their anterior chamber is also significantly less inflamed
Selective laser trabeculoplasty vs Argon laser trabeculoplasty in open angle glaucoma.
No full textPurpose: To compare the effectiveness in lowering the intraocular pressure and the anterior chamber reaction after selective laser trabeculoplasty (SLT) or argon laser trabeculosplasty (ALT).
Methods: Thirty patients aged from 42 to 73 were randomised to treatment with either SLT or ALT. SLT was performed by a 532 nm Nd:YAG laser and ALT by a 532 nm argon laser. Before laser trabeculoplasty we perfomed an evaluation of anterior chamber cellularity with a flare-cell meter (Kowa 500). ALT was performed using 50 applications of 50 μm, 0.1 msec. duration and a power ranged from 450 mW to 620 mW (mean 513.333±48.990). SLT was performed using 50 spots with a size of 400 μm, pulse duration of 3 ns and a power ranged from 0.400 to 0.700 (mean 0.572±0.115). One day after we performed a flare cell meter evaluation. Intraocular pressure was evaluated one day, one week, one and three months after.
Results We treated 24 eyes in each group. Baseline the IOP in the SLT group and in ALT group was 23.263±2.600 mm/Hg vs 22.632±2.967 mm/Hg (p<0.459) the day after treatment we found 18.705±2.800 mm/Hg vs 19.633±2.780 mm/Hg (p<0.430). One month later 16.713±2.100 mm/Hg vs 17.650±2.600 mm/Hg (p<0.390) and after three months 14.842±2.167 mm/Hg vs 16.053±2.223 mm/Hg (p<0.317). The baseline anterior chamber flare-cell in SLT and ALT was 4.600±1.405 photons/ms vs 6.311±3.416 photons/ms (p<0.169) and the day after treatment was 5.960±0.983 photons/ms vs 13.289±2.153 photons/ms (p<0.027).
Conclusions: SLT appears to be statistically equivalent to ALT in lowering IOP during the first three months after treatment even if the SLT patients have a greater drop in IOP. We found a lower anterior chamber reaction one day after SLT
Indagine laser flare-meter nella retinopatia diabetica.
No full textGli autori hanno valutato, mediante laser-flare meter, la cellularità dell'acqueo in pazienti diabetici con vari gradi di retinopatia. Sonos tati studiati 150 pazienti affetti da diabete tipo II non insulino dipendente suddivisi in tre gruppi: gruppo A (50 pz) senza segni di retinopatia diabetica (RD), gruppo B (54 pz) con RD background e gruppo C (46 pz) con RD proliferante. In tuti i pz sonos tati dosati l'emoglobina glicosilata (HbA10) e il tasso ematico di PGI2 inotlre si è provveduto a valutare la cellularità dell'acqueo con laser flare-meter Kowa FM500. I risultati sono stati comparati con quelli di 20 soggetti sani. Per l'analisi statistica abbiamo utilizzato il test t di Student per dati non appaiati e il test di correlazione di SPearman considerando positivo un p<0.05. I valori del flare a livellod ell'acqueo sono risultati essere di 4.681 +/- 0.818 photon/m (Gruppo Controllo), 7.650 +/- 1.834 photon/m (gruppo A), 9.040 +/- 2.984 photon/m (Gruppo B) e 18.730 +/- 3.384 photon/m (Gruppo C), Le percentuali di HbA10 sono risultate rispettivamente di 3.860 +/- 0.937% (Gruppo di COntrollo, 6.570+/- 0.773% (Gruppo A), 9.350 +/- 0.619% (Gruppo B) e di 10.390 +/- 1.369% /Gruppo C) mentre il tasso di PGI2 è risultato essere di 13.540 +/- 1.021 nmol/l (Gruppo COntrollo, 14.670 +/- 1.394 nmol/l (Gruppo A), 17.900 +/- 1.528 nmol/L (Gruppo B) e di 4.910 +/- 0.927 nmol/l (Gruppo C).
Alla luce dei nostri risultati riteniamo che nel diabetico la cellularità dell'acqueo presenti una duplice origine: inizialmente infiammatoria e solo successivamente nella fase proliferativa da rottura della barriera emato-retinica
Analisi della superficie oculare in pazienti affetti da malattie reumatiche.
No full textL'interessamento della superficie oculare è stato studiato in 122 pazienti in corso di sindrome di Sjogren primaria (SSI, n=40), patologia autoimmune non Sjogren (n=51), Sindrome Sicca (n=31), mediante una serie di analisi funzionali e questionario sintomatologico validato. I risultati del nostro lavoro dimostrano come la sintomatologia soggettiva ed una serie di funzioni (secrezione lacrimale basale, il turnover lacrimale, la sensibilità corneale, l'integrità della superficie) della sufperficie oculare appaiano significativamente alterate nella condizione di SSI. I dati ottenuti dimostrano la necessità di ampliare la valutazione del coinvolgimento oculare in corso di malattia reumatica e suggeriscono un percorso più articolato per fornire un più preciso orientamento diagnostico
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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