1,720,980 research outputs found
Optical coherence tomography angiography in myopic peripapillary intrachoroidal cavitation complicated by choroidal neovascularization
Full text linkPurpose: To detect the vessel density (VD) of the radial peripapillary capillary (RPC) in eyes affected by pathological myopia with or without a peripapillary intrachoroidal cavitation (PICC) and in eyes with PICC complicated by choroidal neovascularization (CNV), using optical coherence tomography angiography (OCTA). Methods: We prospectively enrolled highly myopic patients from January 2016 to December 2019 at the Eye Clinic of the University of Naples “Federico II.” We divided included patients into three groups: group 1 including patients with PICC complicated by CNV; group 2 including patients with PICC without complications; group 3 including patients with high myopia without PICC and CNV. One-way analysis of variance (ANOVA) followed by Bonferroni post hoc analysis was used to evaluate differences in VD of radial peripapillary capillary (RPC) in papillary whole, peripapillary regions and its sectors among the three groups. Results: We enrolled 12 highly myopic eyes with PICC complicated by CNV, 21 highly myopic eyes with PICC without CNV and 23 highly myopic eyes without PICC. The myopic eyes with PICC revealed a statistically significant reduction in VD of the RPC comparing to the other groups (p < 0.001), especially in eyes affected by myopic PICC complicated by CNV (p < 0.001). These results were similar analyzing the VD in different sectors of the peripapillary region among the three groups (p < 0.001). Conclusion: OCTA detects the changes in peripapillary vascular density of highly myopic eyes. We demonstrated that the RPC vasculature is significantly influenced by the presence of PICC, especially in myopic eyes developing a CNV
Optical coherence tomography angiography in nonarteritic anterior ischemic optic neuropathy due to optic nerve head drusen
Full text linkOptic nerve head drusen (ONHD) are typically benign hyaline and calcified concretions located within the optic nerve. Initially asymptomatic, they can increase slowly in size and number over time, and they can cause mechanical stress at the axons of the optic nerve and progressively lead to a loss of the visual field and papillary vascular changes. Here, we reported a rare case of a young patient with bilateral ONHD complicated by a nonarteritic anterior ischemic optic neuropathy (NAION) in the right eye. The aim of this case was to evaluate, using optical coherence tomography angiography (OCTA), the vascular network of the papillary region in both eyes in the presence of this ischemic event associated to ONHD. At OCTA examination, the whole papillary region revealed a general rarefaction of the vascular network, but it turned out to be greater in the right eye affected by nonarteritic anterior ischemic optic neuropathy than in fellow eye. Therefore, these findings demonstrated that ONHD may determine significant ischemic events of the optic nerve and OCTA represents a valid and noninvasive tool in the diagnosis and in the pathogenesis of these rare cases of NAION associated to ONHD in young patients
The role of optical coherence tomography angiography in reticular pseudodrusen
No full textBackground: To investigate the changes in retinal and choriocapillaris vessel density (VD) in patients effected by early age-related macular degeneration (AMD) and reticular pseudodrusen (RPD), using Optical Coherence Tomography Angiography (OCTA). Methods: A total of seventy-eight eyes of 78 patients (43 male, 35 female, mean age 72.61 ± 5.15) with non-neovascular AMD (38 eyes with early AMD and 40 eyes with RPD) was recruited in this observational prospective study. Forty eyes of 40 healthy subjects represented the control group. The VD was measured in superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris in different macular regions. Results: There were no significant differences in VD of the SCP and DCP among the controls and the two study groups (p > 0.05). The VD of the choriocapillaris revealed a statistically significant reduction in early AMD and RPD groups respect to controls (p < 0.001). Furthermore, the patients with RPD showed a significantly decreased VD respect to patients with early AMD in different macular regions (p < 0.001). Conclusions: The quantitative analysis of retinal and choriocapillaris blood flow by OCTA provided useful information regarding the vascular changes in non-neovascular AMD patients suggesting that the choriocapillaris loss is mainly involved in the pathogenesis of RPD
The role of quantitative deep capillary plexus in the pathogenesis of type 3 macular neovascularization: an optical coherence tomography angiography study
No full textPurpose: To quantitatively investigate the role of deep capillary plexus (DCP) in patients affected by type 3 macular neovascularization (MNV), compared to patients with reticular pseudodrusen (RPD) eyes and healthy controls, using optical coherence tomography angiography (OCTA). Methods: In this prospective observational study, a total of seventy-eight eyes of 78 patients were included. Group 1 consisted of 40 eyes of 40 patients with stage 1 of type 3 MNV (22 males, 18 females, mean age 73.7, SD ± 6.60) and group 2 included 38 eyes of 38 patients with RPD (17 males, 21 females, mean age 73.2, SD ± 4.55). The control group included 40 eyes of 40 healthy subjects (20 males, 20 females, mean age 71.4, SD ± 6.36 years). We evaluated the retinal vessel density (VD) of superficial capillary plexus (SCP) and deep capillary plexus (DCP) using OCTA. Results: Patients with diagnosis of type 3 MNV showed statistically lower values of VD in DCP with respect to controls and to RPD group (p < 0.001), while there were no statistical differences between RPD and control group in macular region. No significant differences in VD of SCP were detected among the three study groups. Conclusion: OCTA provides a reproducible, non-invasive detailed quantitative analysis of retinal vascular features and changing in early-stage type 3 MNV patients, which allowed to shed the light on the main role of DCP ischemia in the development of type 3 MNV. [Figure not available: see fulltext.]
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
Optical coherence tomography angiography in quiescent choroidal neovascularization associated with choroidal nevus: 5 years follow-up
Full text linkPurpose: To report a case of quiescent choroidal neovascularization (CNV) associated with choroidal nevus using optical coherence tomography angiography (OCTA) during 5 years follow-up. Methods: Observational case report. Results: A 53-year old woman was referred our department with diagnosis of choroidal nevus. At 1 year follow-up, fundus autofluorescence revealed hyper/hypoautofluorescent area, infrared image showed hyperreflective area and enhanced depth imaging OCT presented a shallow pigment epithelium detachment without exudation or hemorrhage. Fluorescein angiography and indocyanine green angiography suspected the presence of CNV. Finally, OCTA confirmed a quiescent CNV with an increased flow area of the vascular lesion without any changes in best-corrected visual acuity. At 20 months and 5 years follow-up, the CNV remained quiescent showing no clinical activity on structural SD-OCT and no changes in CNV morphology on OCTA. Conclusion: This case shows the features of quiescent CNV secondary to choroidal nevus after long-term follow-up. OCTA represents a valid imaging technique that allows to identify the CNV and to monitor its progression over time
Peripapillary vascular density in resolved non-arteritic anterior ischemic optic neuropathy: colocalization between structural and vascular parameters
No full textIntroduction/aims: Non-arteritic anterior ischemic optic neuropathy (NAION) is an acute infarction of the prelaminar anterior optic disc, resulting from the occlusion of posterior ciliary arteries. Here, we evaluated the correlation between structural and vascular features in a case of resolved NAION. Methods: Observational case report. Results: A 50-year-old male patient was referred at an Eye clinic due to an altitudinal visual field defect in the left eye, occurred 9 months before. Fundus examination was unremarkable, while structural SD-OCT reveals retinal nerve fiber layer (RNFL), ganglion cell complex (GCC) thinning associated with reduction of peripapillary vascular density at OCT Angiography. Discussion: We found a precise spatial correlation among RNFL and GCC thinning, peripapillary vascular reduction and visual field defects. This case demonstrates that OCTA represents a new, valid and non-invasive imaging technique in the diagnosis and follow-up of NAION, even after the resolution of the acute phase, in the absence of clinical signs at fundus examination
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
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