1,720,958 research outputs found
Perfluorocarbon liquid assisted large retinal epithelium patching in sub-macular hemorrhage secondary to age related macular degeneration
No full textWe investigate the safety and feasibility of large retinal pigmentary epithelium (RPE)-Choroid-free graft after surgical drainage of massive sub-macular hemorrhage (SMH) due to age-related macular degeneration (ARMD). Four previously untreated patients (three females and one male) underwent to three port pars plana vitrectomy, induction of retinal detachment and peripheral temporal 180A degrees retinotomy. The retina was then folded nasally, to allow access for removal of sub-macular Hg and CNV complex. A full-thickness-large autologus Chorio-RPE patch was grafted. Silicone oil was used as endotemponade for approximately 12 weeks. After removal of silicone oil, the patients were followed-up for 6 months. SMH was completely removed in all cases. It was possible to graft a large RPE patch safely that is sufficiently large to cover the entire defect of macular RPE. At last follow-up, improvement in visual acuity (from 3 +/- 0.9 to 55 +/- 9 ETDRS letters) and recovery of central fixation was observed in all patients. Our surgical technique for large elevated SMH seems to be feasible and efficacious approach to harvest and relocate large RPE patch and to save limited vision in selected patients
Primary vitrectomy with Densiron-68 for rhegmatogenous retinal detachment
No full textBackground To report a retrospective non-comparative interventional study on the effectiveness and ocular tolerance of a heavy silicone oil tamponade (HSO, Densiron-68) for primary inferior rhegmatogenous retinal detachment (RRD). Methods Forty-one eyes of 41 consecutive patients were recruited between January 2004 and August 2006. Primary vitrectomy with Densiron-68, a heavy silicone oil, was used in all cases. Inclusion criteria were primary RRD with at least one retinal break between 4 and 8 clock hours. The study protocol consisted of a minimum of eight clinic visits: baseline, surgery, 1 week, 1 month and 3 months after the initial surgery; removal of oil and 1 week, 1 month and 3 months postoperatively. The primary endpoint was anatomical re-attachment of the retina. Cases were judged successful when there was reattachment of the retina in the absence of any tamponade agent. The secondary endpoint was to record the visual function and any complications arising from the surgery. Out of 41 patients initially included in the study, 33 completed all follow-up visits. Results Anatomical success was achieved in 91% of cases (30 out of 33) with one retinal operation, and rose to 94% (31 out of 33) with additional surgery. Mean visual acuity improved from logMAR 1.19 (SD 0.9) to 0.5 (SD 0.51, p=0.001). No significant ocular hypertension, clinically significant emulsification of the tamponade or inflammation developed during follow-up. Conclusion With Densiron-68, high anatomical and functional success rates can be achieved with primary vitrectomy for RRD and predominantly inferior pathology
Can a preoperative bevacizumab injection prevent recurrent postvitrectomy diabetic vitreous haemorrhage?
No full textAims To evaluate the recurrence rate of vitreous haemorrhage (VH) in patients treated with one intravitreal bevacizumab (IVB) injection (2.5 mg/0.1 ml) before planned pars plana vitrectomy for treatment of diabetic non-clearing VH. Methods Prospective pilot study of 32 eyes of 31 consecutive diabetic patients who underwent IVB injection within 1 week before surgery for persistent VH in the presence of active proliferative diabetic retinopathy. Three masked retinal specialists graded the amount of VH from grade 0 to grade 3 with slit-lamp biomicroscopy. Main outcome measures were the rate of recurrence of the VH, improvement in visual acuity, incidence of cataract formation, and postoperative complications through a follow-up of 6 months. Results The percentage of severe recurrent VH with no fundus details (grade 3) was 3% at 1 week follow-up and 3, 6, and 6% respectively at 1-, 3-, and 6-month follow-up. The mean best-corrected visual acuity (BCVA) improved from 1.6 (1/60) to 0.40 (6/15) logMAR (P - 0.02) in 29 out of 32 eyes (91%). In all, 12 out of 22 (54%) phakic eyes developed cataract during the follow-up period, and 10 (31%) of them underwent cataract surgery. Conclusions Our study suggests that IVB injection few days before planned surgery seems to be efficacious and safe as an adjuvant treatment to prevent rebleeding in eyes undergoing pars plana vitrectomy for treatment of diabetic vitreous haemorrhage. IVB facilitates the surgery and reduces the need for extensive delamination and segmentation, decreasing the possibility of significant early active postoperative VH. Eye (2009) 23, 1698-1701; doi: 10.1038/eye.2008.354; published online 28 November 200
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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