1,720,981 research outputs found
Optical Coherence Tomography Angiography Features in Post-COVID-19 Pneumonia Patients: A Pilot Study
Full text linkPurpose: This study investigated changes in retinal vessel density in macular and papillary regions in post-SARS-CoV-2 pneumonia patients by means of optical coherence tomography angiography (OCTA). Design: Prospective, observational, cohort study. Methods: Forty eyes of 40 patients (mean age: 49.7 ± 12.6 years old) post-SARS-CoV-2 infection and 40 healthy subjects were enrolled in this study. COVID-19 patients had to be fully recovered from COVID-19 pneumonia and were evaluated 6 months after COVID-19 infection. The primary outcome resulted from OCTA studies of the following vascular structures: vessel density (VD) in the retinal superficial capillary plexus (SCP), deep capillary plexus (DCP), and radial peripapillary capillaries (RPC) compared to those of controls. Structural spectral domain (SD)-OCT parameters were also evaluated: ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL). Results: The patients showed a significant reduction in VD of the SCP in whole images and in the DCP in all sectors compared to those in healthy subjects (P <.05). COVID-19 patients featured a reduced VD of the RPC compared to that in controls (P <.001). No differences were found in the GCC, whereas the RNFL was reduced in the COVID-19 group compared to that in controls (P = .012). Significant correlations were found between the RNFL and VD of the SCP, DCP, RPC, and FAZ area in the COVID-19 group (P <.05). Conclusions: OCTA showed retinal vascular changes in subjects fully recovered from COVID-19 pneumonia. These findings could be a consequence of a thrombotic microangiopathy that affected retinal structures as well as other systemic organs. OCTA could represent a valid, noninvasive biomarker of early vascular dysfunction after SARS-CoV-2 infection
Optical Coherence Tomography Angiography Findings After Intravitreal Ranibizumab in Patients With Coats Disease
Full text link: The aim of this retrospective study was to describe the vascular features in eyes with Coats disease, using optical coherence tomography angiography (OCTA), at baseline and after 3 monthly intravitreal injections of ranibizumab. Fifteen eyes of 15 consecutive patients affected by Coats' disease were recruited in this study. All patients underwent the best-corrected visual acuity (BCVA) evaluation, fundus examination, fluorescein angiography (FA), indocyanine green angiography (ICGA), multicolor imaging, structural Spectral Domain (SD)-OCT and OCTA at baseline and 1 month after the third monthly ranibizumab injection (loading phase). Fifteen patients completed the study, of whom nine were males and six females. Mean age was 20.4 ± 2 years. BCVA was 0.46 ± 0.11 logMar and 0.47 ± 0.12 logMar at baseline and after treatment, respectively (p = 0.164). SD-OCT revealed no significant decrease in central macular thickness (486.33 μm ± 93.37 at baseline vs. 483.4 μm ± 80.97 after treatment; p = 0.915). The subretinal exudates persisted in macular region after intravitreal injections. OCTA showed a general vascular rarefaction in superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillary (CC) that did not change after loading phase. This study showed no functional and vascular improvement following 3 monthly ranibizumab injections. OCTA, non-invasive technique, could be useful during follow up of these patients and provide a better understand of pathogenesis of this disorder
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
Mid-term safety and effectiveness of macular peeling one month after intravitreal dexamethasone implant for tractional diabetic macular edema
Full text linkMacular peeling combined or followed by intravitreal dexamethasone implant (DEX-i) was recommended as an efficacy approach for tractional diabetic macular edema (tDME). Knowing the synergistic effect of cataract surgery and DEX-i one month earlier in eyes with DME, we compared Epiretinal Membrane/Inner Limiting Membrane (ERM/ILM) peeling preceded by DEX-i one month before versus ERM/ILM peeling alone for the treatment of tDME. A retrospective study on patients affected by tDME who underwent ERM/ILM peeling one month after DEX-i (n = 11; Group A) or ERM/ILM peeling alone (n = 10; Group B) was performed. Longitudinal comparison of best-correct visual acuity (BCVA), central retinal thickness (CRT), and intraocular pressure (IOP) between the time of surgery (T0) and each time point (months 1,3,5,6) within and among the groups were assessed. To evaluate the repeated measurements of BCVA, CRT, and IOP, a linear mixed-effects model was used. In Group A, DEX-i significantly improved mean BCVA and CRT (P < 0.001) just after 1 month (T0). After ERM/ILM peeling, mean BCVA and CRT significantly improved from month 1 in Group A and month 3 in Group B. Mixed model revealed a significant difference in BCVA (P ≤ 0.0001) and CRT (P ≤ 0.02) at different time-points among the groups with better results in Group A. Neither complications nor uncontrolled IOP increase was detected. ERM/ILM peeling confirmed its effectiveness in treating tDME. DEX-i performed one month before surgery seemed to be a safe approach and ensured a greater and faster recovery considering functional and tomographic parameters
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
Risk of acute stroke in patients with retinal artery occlusion: a systematic review and meta-analysis
No full textObjectiveTo estimate the incidence of acute cerebral ischaemia detected by magnetic resonance imaging (MRI) in acute central retinal artery occlusion (CRAO), branch retinal artery occlusion (BRAO) and transient monocular vision loss (TMVL).MethodsStudies reporting the incidence of acute cerebral ischaemia, detected by MRI, within 7 days from diagnosis of acute CRAO, BRAO and TMVL up to January 2019 were systematically searched for on Pubmed, Medline and Cochrane Library. Meta-analysis was performed using random effects model. The primary outcome was the pooled estimate of incidence of acute cerebral ischaemia in CRAO, BRAO and TMVL cohorts including both neurologically symptomatic and asymptomatic patients, expressed as a proportion along with 95% confidence intervals (CIs). The pooled estimate of incidence of asymptomatic acute cerebral ischaemia represented a secondary outcome measure.ResultsFor the primary outcome, the pooled proportion of acute cerebral ischaemia was 0.30 (CI 0.24–0.36) in the CRAO cohort, and 0.25 (CI 0.16–0.37) in the BRAO cohort, without statistical heterogeneity. The rate of acute cerebral ischaemia was 11.8% in the TMVL cohort. For the secondary outcome, the pooled proportion of asymptomatic acute cerebral ischaemia was 0.22 (CI 0.16–0.28) in the CRAO cohort, 0.29 (CI 0.20–0.41) in the BRAO cohort and 0.08 (CI 0.05–0.15) in the TMVL cohort, with no statistical heterogeneity.Conclusions30% of patients with acute CRAO and 25% of patients with acute BRAO presented an acute cerebral ischaemia on MRI. Such high rates support a care pathway of prompt referral of such patients for neurological evaluation and brain imaging.<br/
Vitrectomy in Small idiopathic MAcuLar hoLe (SMALL) study: Internal limiting membrane peeling versus no peeling
No full textPurpose: To compare vitrectomy with and without internal limiting membrane (ILM) peeling in small idiopathic macular holes. Methods: Retrospective multicentre study including consecutive eyes with ≤250 μm idiopathic macular hole treated with vitrectomy. The primary outcome was hole closure rate. Best-corrected visual acuity (BCVA) change, closure patterns on optical coherence tomography, rates of external limiting membrane (ELM) and ellipsoid zone (EZ) recovery, and rate of complications were also investigated. Results: In total, 693 eyes were included. Hole closure rate was 98% in the peeling and 85% in the no-peeling group (p < 0.001). At 12 months, mean BCVA change was 0.38 ± 0.22 logMAR in the peeling and 0.45 ± 0.21 logMAR in the no-peeling group (p = 0.02); 66% versus 80% of eyes had a U-shaped morphology, respectively; EZ recovery rate was 75% and 93%, respectively (p = 0.02). In the no-peeling group, eyes with a vitreomacular traction (VMT) showed a 96% closure rate, comparable to the peeling group (p = 0.40). The incidence of adverse events was similar except for dissociated optic nerve fibre layer (55% in the peeling vs. 9% in the no-peeling group, p < 0.001). Conclusions: In small idiopathic macular holes, ILM peeling provides a higher closure rate compared to no-peeling; however, if a VMT is present closure rates are comparable. In closed macular holes, the no-peeling technique provides advantages in terms of visual outcome and anatomical recovery
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
- …
