1,720,978 research outputs found
TWENTY-THREE-GAUGE PARS PLANA VITRECTOMY, DENSIRON-68, AND 360 degrees ENDOLASER VERSUS COMBINED 20-GAUGE PARS PLANA VITRECTOMY, SCLERAL BUCKLE, AND SF6 FOR PSEUDOPHAKIC RETINAL DETACHMENT WITH INFERIOR RETINAL BREAKS
No full textPurpose: To compare the anatomical and functional outcomes of 23-gauge pars plana vitrectomy (PPV) with Densiron-68 tamponade and 360 degrees endolaser versus 20-gauge PPV with encircling scleral buckling (ESB) and an SF6 gas tamponade for the repair of primary pseudophakic retinal detachment with inferior retinal breaks. Methods: Prospective, randomized, comparative, interventional study. Eighty-two eyes of 82 consecutive patients were randomly assigned to 1 of the 2 treatment groups: 23-gauge PPV/Densiron-68 (44 eyes, 54%) or 20-gauge PPV/ESB/SF6 (20%) (38 eyes, 46%). The inclusion criterion was the presence of primary pseudophakic retinal detachment with at least 1 retinal break between the 4- and 8-o'clock positions. The study protocol involved a minimum of 7 visits: baseline, day of surgery, 1 week, and 1, 3, 6, and 9 months postoperation. Densiron-68 removal was performed within 12 weeks of the initial surgery. Two surgical procedures were required in the Densiron group to remove the oil. Results: After the primary procedure, the retina was reattached in 90% (40 of 44) of cases in the 23-gauge PPV/Densiron group and in 92% (35 of 38) of cases in the 20-gauge PPV/ESB/SF6 group (P=0.2, Fisher's exact test). After resolution of redetachments, final anatomical success rate rose to 97% (43 of 44) in the 23-gauge PPV/Densiron group and 94% (36 of 38) in the 20-gauge PPV/SB/SF6 group (P=0.32, Fisher's exact test). Mean final best-corrected visual acuity (logarithm of the minimum angle of resolution) was 0.40 in the 23-gauge PPV/Densiron group and 0.48 in the 20-gauge PPV/ESB/SF6 group (P=0.31, t-test). Operative time was significantly less in the 23-gauge PPV/Densiron group (P=0.002, t-test). No statistically significant difference in the complication rate between the two groups was recorded. Conclusion: Twenty-three-gauge PPV combined with Densiron-68 and 360 degrees endolaser and 20-gauge PPV combined with ESB/SF6 seemed to have similar efficacy in the repair of primary pseudophakic retinal detachment. Supplementary scleral buckling can be avoided using a Densiron-68 tamponade for retinal detachment with inferior retinal breaks. RETINA 31: 686-691, 201
Sub-Macular Surgery: Is Still an Option for Age-Related Macular Degeneration?
No full textPurpose: This review summarizes the data reported in peer-reviewed literature on the effects of submacular surgery for age-related macular degeneration (AMD) associated with choriodal neovascularization (CNV). Methods: A review of the MEDLINE database has been performed in order to examine the therapeutic effects of submacular surgical treatments in patients affected by AMD. Results: The multicenter studies conducted by the Submacular Surgery Trials Research Group compare the removal of the CNV complex, both with (336) and without blood (454), with observation in patients affected by AMD. At a 1-year follow-up, no benefit in preventing visual loss had been shown. Furthermore, complications occurred in the surgery arm such as retinal detachment and lens opacification. No differences have been found between submacular surgery and laser photocoagulation in terms of visual acuity and quality of life. As yet, there are no randomized controlled trials concerning retinal pigment epithelium and choroid translocation or macular translocation, but only prospective, non-controlled case series with low quality of evidence. Conclusions: No evidence of potential benefit from submacular removal of the CNV complex due to AMD has been shown. Randomized clinical trails (RCT) concerning other submacular surgical approaches are not available. There are sufficient non-comparative data on retinal pigment epithelium (RPE) graft to warrant an RCT especially in patients with large subretinal haemorrhages, RPE rip or in Anti-VEGF non-responders
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
Evaluación de los cambios vasculares en la mácula en pacientes con desprendimiento de retina regmatógeno mediante el uso de un software de estudio semiautomático de angiografía por tomografía de coherencia óptica
Full text linkIntroducció: El despreniment de retina regmatogen (DRR) és una condició greu que afecta l'agudesa visual i requereix una intervenció quirúrgica urgent. La visió postoperatòria depèn de diversos factors, entre ells els canvis en la microvasculatura retiniana, la qual pot ser estudiada utilitzant l'angiografia per tomografia de coherència òptica (OCTA). Objectiu: Demostrar l'existència de canvis vasculars en els ulls amb despreniment de retina regmatogen abans i després de la cirurgia vitreoretiniana de reparació, mesurats a través d'un software d'estudi semiautomàtic en imatges de OCTA. Mètodes: Es va dissenyar un estudi prospectiu i observacional amb 67 pacients sotmesos a VPP per DRR primari no complicat entre maig de 2020 i juny de 2021. Es van excloure 18 pacients per miopia alta, malalties oculars concomitants o baixa qualitat de les imatges. Es van realitzar avaluacions oftalmològiques completes i imatges de l'OCTA preoperatories i als 1, 3 i 6 mesos postcirurgia. Es va utilitzar un software semiautomàtic per quantificar els canvis i analitzar la morfologia vascular. Resultats: Els pacients es van agrupar segons l'estat preoperatori de la màcula en dos grups: màcula ON i màcula OFF. En el grup màcula ON, els índexs de diàmetre i densitat vascular (VDI i VAD) preoperatoris van ser significativament inferiors en els ulls afectats en comparació amb l'ull contralateral, especialment en el plexe capil·lar profund. En el grup màcula OFF, el VDI va ser significativament inferior en ambdós plexes, i la densitat de vasos esqueletitzats (VSD) en el plexe superficial va augmentar. En el grup màcula ON, un 34,8% dels pacients van experimentar una millora visual significativa (≥ 0,1 LogMAR) al sisè mes. Els paràmetres preoperatoris VDI i VSD van resultar ser predictors de millora visual en aquest grup. En el grup màcula OFF, la recuperació visual va ser més variable, amb una tendència a la millora dels paràmetres vasculars, tot i que no es va assolir significació estadística. L'agudesa visual preoperatòria va ser el principal factor pronòstic en aquest grup. Conclusions: Es van trobar canvis microvasculars significatius en ambdós grups de DRR en comparació amb els ulls contralaterals. Aquests canvis es relacionen amb l'agudesa visual, sent factors predictors en el grup màcula ON. En el grup màcula OFF, només l'agudesa visual preoperatòria va ser útil com a biomarcador de recuperació visual. L'anàlisi mitjançant OCTA i aquest nou software d'estudi va permetre caracteritzar la morfologia vascular i els seus canvis durant l'evolució clínica del DRR.Introducción: El desprendimiento de retina regmatógeno (DRR) es una condición grave que afecta la agudeza visual y requiere intervención quirúrgica urgente. La visión postoperatoria depende de varios factores, entre ellos los cambios en la microvasculatura retiniana, la cual puede ser estudiada utilizando la angiografía por tomografía de coherencia óptica (OCTA). Objetivo: Demostrar la existencia de cambios vasculares en los ojos con desprendimiento de retina regmatógeno antes y después de la cirugía vitreorretiniana de reparación, medidos a través de un software de estudio semiautomático en imágenes de OCTA. Métodos: Se diseñó un estudio prospectivo y observacional con 67 pacientes sometidos a VPP por DRR primario no complicado entre mayo de 2020 y junio de 2021. Se excluyeron 18 pacientes por miopía alta, enfermedades oculares concomitantes o baja calidad de imágenes. Se realizaron evaluaciones oftalmológicas completas e imágenes de OCTA preoperatorias y a los 1, 3 y 6 meses postcirugía, se utilizó un software semiautomático para cuantificar los cambios y analizar la morfología vascular. Resultados: Los pacientes se agruparon según el estado preoperatorio de la mácula en dos grupos: mácula ON y mácula OFF. En el grupo mácula ON, los índices de diámetro y densidad vascular (VDI y VAD) preoperatorios fueron significativamente menores en los ojos afectados comparados con el ojo contralateral, especialmente en el plexo capilar profundo. En el grupo mácula OFF, el VDI fue significativamente menor en ambos plexos, y la densidad de vasos esqueletonizados (VSD) en el plexo superficial aumentó. En el grupo mácula ON, un 34,8% de los pacientes experimentó una mejoría visual significativa (≥ 0,1 LogMAR) al sexto mes. Los parámetros preoperatorios VDI y VSD resultaron ser predictores de mejoría visual en este grupo. En el grupo mácula OFF, la recuperación visual fue más variable, con una tendencia a la mejoría en los parámetros vasculares, aunque sin alcanzar significancia estadística. La agudeza visual preoperatoria fue el principal factor pronóstico en este grupo. Conclusiones: Se encontraron cambios microvasculares significativos en ambos grupos de DRR comparados con los ojos contralaterales. Estos cambios se relacionan con la agudeza visual, siendo factores predictivos en el grupo mácula ON. En el grupo mácula OFF, solo la agudeza visual preoperatoria fue útil como biomarcador de recuperación visual. El análisis mediante OCTA y este nuevo software de estudio permitió caracterizar la morfología vascular y sus cambios durante la evolución clínica del DRR.Introduction: Rhegmatogenous retinal detachment (RRD) is a serious condition that affects visual acuity and requires urgent surgical intervention. Postoperative visual acuity depends on several factors, including changes in retinal microvasculature, which can be studied using optical coherence tomography angiography (OCTA). Objective: To demonstrate the existence of vascular changes in eyes with rhegmatogenous retinal detachment before and after vitreoretinal surgery, measured by a semi-automated software in OCTA images. Methods: A prospective and observational study was designed with 67 patients who underwent 25G pars plana vitrectomy (PPV) for uncomplicated primary RRD between May 2020 and June 2021. Eighteen patients were excluded due to high myopia, concomitant ocular diseases, or poor image quality. Complete ophthalmological evaluations and OCTA images were obtained preoperatively and at 1, 3, and 6 months post-surgery. A semi-automated software was used to quantify the vascular changes and analyze vascular morphology. Results: Patients were grouped according to the preoperative status of the macula into groups: macula ON and macula OFF. In the macula ON group, preoperative vascular diameter index (VDI) and vascular area density (VAD) were significantly lower in affected eyes compared to the contralateral eye, particularly in the deep capillary plexus. In the macula OFF group, VDI was significantly lower in both plexuses, and the skeleton vessel density (VSD) in the superficial plexus increased. In the macula ON group, 34.8% of patients experienced a significant visual improvement (≥ 0.1 LogMAR) at six months. Preoperative VDI and VSD parameters were predictors of visual acuity improvement in this group. In the macula OFF group, final visual acuity outcomes were variable, showing a trend toward improvement in vascular parameter measurements, although this did not achieve statistical significance. Preoperative visual acuity emerged as the primary prognostic factor in this group. Conclusions: Significant microvascular changes were found in both RRD groups compared to contralateral eyes. These changes were related to visual acuity, acting as predictive factors in the macula ON group. In the macula OFF group, only preoperative visual acuity served as a predictor of visual recovery. OCTA analysis and this semi-automatic software allowed for the characterization of vascular morphology and its changes during follow-up of RRD
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