The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
George A. Williams - One of the best experts on this subject based on the ideXlab platform.
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Sutureless scleral Fixation of intraocular lenses: outcomes of two approaches. The 2014 Yasuo Tano Memorial Lecture
Graefe's Archive for Clinical and Experimental Ophthalmology, 2015Co-Authors: Ashkan M. Abbey, Rehan M. Hussain, Ankoor R. Shah, Lisa J. Faia, Jeremy D. Wolfe, George A. WilliamsAbstract:Purpose We sought to assess the clinical outcomes and complications of two approaches to scleral Fixation of intraocular lenses (IOLs): transconjunctival Fixation through trocar cannulas and Fixation using scleral tunnels created with a microvitreoretinal (MVR) blade. Methods This retrospective chart review was comprised of 23 eyes that received scleral Fixation of a three-piece IOL with concurrent pars plana vitrectomy between June 2012 and June 2014. Scleral Fixation was performed either by transconjunctival Fixation through trocar cannulas (cannula Fixation) or by the creation of scleral tunnels using an MVR blade (tunnel Fixation). The preoperative and postoperative corrected distance visual acuities (CDVA), spherical equivalents (SE), and complications were evaluated. Results 15 cannula Fixations and 8 tunnel Fixations were performed. Mean follow-up was 353 days (Range: 94 – 790 days). Fifteen IOLs were fixated 2 mm posterior to the limbus. Seven IOLs were fixated 1.5 mm posterior to the limbus, and one IOL was fixated 0.75 mm posterior to the limbus. Mean preoperative CDVA was logMAR 1.17 (Snellen 20/297), and mean postoperative CDVA was logMAR 0.37 (Snellen 20/47) ( p
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Sutureless scleral Fixation of intraocular lenses: outcomes of two approaches. The 2014 Yasuo Tano Memorial Lecture
Graefe's Archive for Clinical and Experimental Ophthalmology, 2015Co-Authors: Ashkan M. Abbey, Rehan M. Hussain, Ankoor R. Shah, Lisa J. Faia, Jeremy D. Wolfe, George A. WilliamsAbstract:Purpose We sought to assess the clinical outcomes and complications of two approaches to scleral Fixation of intraocular lenses (IOLs): transconjunctival Fixation through trocar cannulas and Fixation using scleral tunnels created with a microvitreoretinal (MVR) blade. Methods This retrospective chart review was comprised of 23 eyes that received scleral Fixation of a three-piece IOL with concurrent pars plana vitrectomy between June 2012 and June 2014. Scleral Fixation was performed either by transconjunctival Fixation through trocar cannulas (cannula Fixation) or by the creation of scleral tunnels using an MVR blade (tunnel Fixation). The preoperative and postoperative corrected distance visual acuities (CDVA), spherical equivalents (SE), and complications were evaluated. Results 15 cannula Fixations and 8 tunnel Fixations were performed. Mean follow-up was 353 days (Range: 94 – 790 days). Fifteen IOLs were fixated 2 mm posterior to the limbus. Seven IOLs were fixated 1.5 mm posterior to the limbus, and one IOL was fixated 0.75 mm posterior to the limbus. Mean preoperative CDVA was logMAR 1.17 (Snellen 20/297), and mean postoperative CDVA was logMAR 0.37 (Snellen 20/47) ( p
René M. Müri - One of the best experts on this subject based on the ideXlab platform.
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visual exploration area in neglect a new analysis method for video oculography data based on foveal vision
Frontiers in Neuroscience, 2020Co-Authors: Brigitte C Kaufmann, René M. Müri, Dario Cazzoli, Samuel E J Knobel, Thomas NyffelerAbstract:Video-oculography during Free Visual Exploration (FVE) is a valuable tool to evaluate visual attention spatial allocation in neglect patients after right-hemispheric stroke. In conventional FVE analyses, the position of a visual Fixation is conceived as a single point in space. Here, we describe a new, complementary method to analyse FVE data, based on foveal vision, leading to an accurate estimate of the portion of the picture that was effectively explored. In 15 neglect patients and 20 healthy controls, visual exploration areas (i.e., considering 1°visual angle around every single Fixation) were computed. Furthermore, the proportion of single and overlapping Fixations was analysed. Overlapping Fixations were further categorized into capture Fixations (successive overlapping Fixation, putatively reflecting problem of disengagement) and re-capture Fixations (temporally distant overlapping Fixations, putatively reflecting spatial working memory deficits). The results of this new analysis approach were compared to the ones of conventional approaches. Conventional analyses showed the typical visual attention deficits in neglect patients versus healthy controls: significantly less Fixations and time spent within the left, and significantly more Fixations and time spent within the right screen half. According the results of our new approach, patients showed a significantly smaller visual exploration area within the left screen half. However, the right visual exploration area did not differ between groups. Furthermore, in neglect patients, the proportion of overlapping Fixations within the right screen half was significantly higher than within the left screen half, as well as significantly higher than in healthy controls within either screen halves. Whereas neglect patients showed significantly more capture Fixations than healthy controls, the number of re-capture Fixations did not differ between groups. These results suggest that, in neglect patients, the efficiency of visual exploration is also reduced within the right screen half and that impaired disengagement might be an important mechanism leading to overlapping Fixations. Our new analysis of the visual exploration area, based on foveal vision, may be a promising, additional approach in visual attention research. It allows to accurately measure the portion of the picture that was effectively explored, disentangle single from overlapping Fixations, and distinguish between capture and re-capture Fixations.
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re Fixation and perseveration patterns in neglect patients during free visual exploration
European Journal of Neuroscience, 2019Co-Authors: Rebecca Elise Paladini, Dario Cazzoli, Brigitte C Kaufmann, Thomas Nyffeler, Patric Wyss, Prabitha Urwyler, Tobias Nef, René M. MüriAbstract:The literature suggests that neglect patients not only show impairments in directing attention toward the left, contralesional space, but also present with perseverative behavior. Moreover, previous studies described re-Fixations during visual search tasks, and interpreted this finding as an impairment of spatial working memory. The aim of the present study was to study re-Fixations and perseverations (i.e., recurrent re-Fixations to same locations) during free visual exploration, a task with high ecological validity. We hypothesized that: (1) neglect patient would perform re-Fixations more frequently than healthy controls within the right hemispace; and, (2) the re-Fixation behavior of neglect patients would be characterized by perseverative Fixations. To test these hypotheses, we assessed 22 neglect patients and 23 healthy controls, measuring their eye movements during free exploration of naturalistic pictures. The results showed that neglect patients tend to re-fixate locations within the ipsilesional hemispace when they freely explore naturalistic pictures. Importantly, the saliency of discrete locations within the pictures has a stronger influence on Fixation behavior within the contralesional than within the ipsilesional hemispace in neglect patients. Finally, the results indicated that, for re-Fixations, saliency plays a more important role within the contralesional than the ipsilesional hemispace. Moreover, we found evidence that re-Fixation behavior of neglect patients is characterized by frequent recurrent re-Fixations back to the same spatial locations which may be interpreted as perseverations. Hence, with the present study, we could better elucidate the mechanism leading to re-Fixations and perseverative behavior during free visual exploration in neglect patients.
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Visual exploration behaviour during clock reading in Alzheimer's disease.
Brain, 2004Co-Authors: Urs Peter Mosimann, Jacques Felblinger, Pietro Ballinari, C. W. Hess, René M. MüriAbstract:Eye movement behaviour during visual exploration of 24 patients with probable Alzheimer's disease and 24 age-matched controls was compared in a clock reading task. Controls were found to focus exploration on distinct areas at the end of each clock hand. The sum of these two areas of highest Fixation density was defined as the informative region of interest (ROI). In Alzheimer's disease patients, visual exploration was less focused, with fewer Fixations inside the ROI, and the time until the first Fixation was inside the ROI was significantly delayed. Changes of Fixation distribution correlated significantly with the ability to read the clock correctly, but did not correlate with dementia severity. In Alzheimer's disease patients, Fixations were longer and saccade amplitudes were smaller. The altered visual exploration in Alzheimer's disease might be related to parietal dysfunction or to an imbalance between a degraded occipito-parietal and relatively preserved occipito-temporal visual network.
Ashkan M. Abbey - One of the best experts on this subject based on the ideXlab platform.
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Sutureless scleral Fixation of intraocular lenses: outcomes of two approaches. The 2014 Yasuo Tano Memorial Lecture
Graefe's Archive for Clinical and Experimental Ophthalmology, 2015Co-Authors: Ashkan M. Abbey, Rehan M. Hussain, Ankoor R. Shah, Lisa J. Faia, Jeremy D. Wolfe, George A. WilliamsAbstract:Purpose We sought to assess the clinical outcomes and complications of two approaches to scleral Fixation of intraocular lenses (IOLs): transconjunctival Fixation through trocar cannulas and Fixation using scleral tunnels created with a microvitreoretinal (MVR) blade. Methods This retrospective chart review was comprised of 23 eyes that received scleral Fixation of a three-piece IOL with concurrent pars plana vitrectomy between June 2012 and June 2014. Scleral Fixation was performed either by transconjunctival Fixation through trocar cannulas (cannula Fixation) or by the creation of scleral tunnels using an MVR blade (tunnel Fixation). The preoperative and postoperative corrected distance visual acuities (CDVA), spherical equivalents (SE), and complications were evaluated. Results 15 cannula Fixations and 8 tunnel Fixations were performed. Mean follow-up was 353 days (Range: 94 – 790 days). Fifteen IOLs were fixated 2 mm posterior to the limbus. Seven IOLs were fixated 1.5 mm posterior to the limbus, and one IOL was fixated 0.75 mm posterior to the limbus. Mean preoperative CDVA was logMAR 1.17 (Snellen 20/297), and mean postoperative CDVA was logMAR 0.37 (Snellen 20/47) ( p
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Sutureless scleral Fixation of intraocular lenses: outcomes of two approaches. The 2014 Yasuo Tano Memorial Lecture
Graefe's Archive for Clinical and Experimental Ophthalmology, 2015Co-Authors: Ashkan M. Abbey, Rehan M. Hussain, Ankoor R. Shah, Lisa J. Faia, Jeremy D. Wolfe, George A. WilliamsAbstract:Purpose We sought to assess the clinical outcomes and complications of two approaches to scleral Fixation of intraocular lenses (IOLs): transconjunctival Fixation through trocar cannulas and Fixation using scleral tunnels created with a microvitreoretinal (MVR) blade. Methods This retrospective chart review was comprised of 23 eyes that received scleral Fixation of a three-piece IOL with concurrent pars plana vitrectomy between June 2012 and June 2014. Scleral Fixation was performed either by transconjunctival Fixation through trocar cannulas (cannula Fixation) or by the creation of scleral tunnels using an MVR blade (tunnel Fixation). The preoperative and postoperative corrected distance visual acuities (CDVA), spherical equivalents (SE), and complications were evaluated. Results 15 cannula Fixations and 8 tunnel Fixations were performed. Mean follow-up was 353 days (Range: 94 – 790 days). Fifteen IOLs were fixated 2 mm posterior to the limbus. Seven IOLs were fixated 1.5 mm posterior to the limbus, and one IOL was fixated 0.75 mm posterior to the limbus. Mean preoperative CDVA was logMAR 1.17 (Snellen 20/297), and mean postoperative CDVA was logMAR 0.37 (Snellen 20/47) ( p
Thomas Nyffeler - One of the best experts on this subject based on the ideXlab platform.
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visual exploration area in neglect a new analysis method for video oculography data based on foveal vision
Frontiers in Neuroscience, 2020Co-Authors: Brigitte C Kaufmann, René M. Müri, Dario Cazzoli, Samuel E J Knobel, Thomas NyffelerAbstract:Video-oculography during Free Visual Exploration (FVE) is a valuable tool to evaluate visual attention spatial allocation in neglect patients after right-hemispheric stroke. In conventional FVE analyses, the position of a visual Fixation is conceived as a single point in space. Here, we describe a new, complementary method to analyse FVE data, based on foveal vision, leading to an accurate estimate of the portion of the picture that was effectively explored. In 15 neglect patients and 20 healthy controls, visual exploration areas (i.e., considering 1°visual angle around every single Fixation) were computed. Furthermore, the proportion of single and overlapping Fixations was analysed. Overlapping Fixations were further categorized into capture Fixations (successive overlapping Fixation, putatively reflecting problem of disengagement) and re-capture Fixations (temporally distant overlapping Fixations, putatively reflecting spatial working memory deficits). The results of this new analysis approach were compared to the ones of conventional approaches. Conventional analyses showed the typical visual attention deficits in neglect patients versus healthy controls: significantly less Fixations and time spent within the left, and significantly more Fixations and time spent within the right screen half. According the results of our new approach, patients showed a significantly smaller visual exploration area within the left screen half. However, the right visual exploration area did not differ between groups. Furthermore, in neglect patients, the proportion of overlapping Fixations within the right screen half was significantly higher than within the left screen half, as well as significantly higher than in healthy controls within either screen halves. Whereas neglect patients showed significantly more capture Fixations than healthy controls, the number of re-capture Fixations did not differ between groups. These results suggest that, in neglect patients, the efficiency of visual exploration is also reduced within the right screen half and that impaired disengagement might be an important mechanism leading to overlapping Fixations. Our new analysis of the visual exploration area, based on foveal vision, may be a promising, additional approach in visual attention research. It allows to accurately measure the portion of the picture that was effectively explored, disentangle single from overlapping Fixations, and distinguish between capture and re-capture Fixations.
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re Fixation and perseveration patterns in neglect patients during free visual exploration
European Journal of Neuroscience, 2019Co-Authors: Rebecca Elise Paladini, Dario Cazzoli, Brigitte C Kaufmann, Thomas Nyffeler, Patric Wyss, Prabitha Urwyler, Tobias Nef, René M. MüriAbstract:The literature suggests that neglect patients not only show impairments in directing attention toward the left, contralesional space, but also present with perseverative behavior. Moreover, previous studies described re-Fixations during visual search tasks, and interpreted this finding as an impairment of spatial working memory. The aim of the present study was to study re-Fixations and perseverations (i.e., recurrent re-Fixations to same locations) during free visual exploration, a task with high ecological validity. We hypothesized that: (1) neglect patient would perform re-Fixations more frequently than healthy controls within the right hemispace; and, (2) the re-Fixation behavior of neglect patients would be characterized by perseverative Fixations. To test these hypotheses, we assessed 22 neglect patients and 23 healthy controls, measuring their eye movements during free exploration of naturalistic pictures. The results showed that neglect patients tend to re-fixate locations within the ipsilesional hemispace when they freely explore naturalistic pictures. Importantly, the saliency of discrete locations within the pictures has a stronger influence on Fixation behavior within the contralesional than within the ipsilesional hemispace in neglect patients. Finally, the results indicated that, for re-Fixations, saliency plays a more important role within the contralesional than the ipsilesional hemispace. Moreover, we found evidence that re-Fixation behavior of neglect patients is characterized by frequent recurrent re-Fixations back to the same spatial locations which may be interpreted as perseverations. Hence, with the present study, we could better elucidate the mechanism leading to re-Fixations and perseverative behavior during free visual exploration in neglect patients.
Rehan M. Hussain - One of the best experts on this subject based on the ideXlab platform.
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Sutureless scleral Fixation of intraocular lenses: outcomes of two approaches. The 2014 Yasuo Tano Memorial Lecture
Graefe's Archive for Clinical and Experimental Ophthalmology, 2015Co-Authors: Ashkan M. Abbey, Rehan M. Hussain, Ankoor R. Shah, Lisa J. Faia, Jeremy D. Wolfe, George A. WilliamsAbstract:Purpose We sought to assess the clinical outcomes and complications of two approaches to scleral Fixation of intraocular lenses (IOLs): transconjunctival Fixation through trocar cannulas and Fixation using scleral tunnels created with a microvitreoretinal (MVR) blade. Methods This retrospective chart review was comprised of 23 eyes that received scleral Fixation of a three-piece IOL with concurrent pars plana vitrectomy between June 2012 and June 2014. Scleral Fixation was performed either by transconjunctival Fixation through trocar cannulas (cannula Fixation) or by the creation of scleral tunnels using an MVR blade (tunnel Fixation). The preoperative and postoperative corrected distance visual acuities (CDVA), spherical equivalents (SE), and complications were evaluated. Results 15 cannula Fixations and 8 tunnel Fixations were performed. Mean follow-up was 353 days (Range: 94 – 790 days). Fifteen IOLs were fixated 2 mm posterior to the limbus. Seven IOLs were fixated 1.5 mm posterior to the limbus, and one IOL was fixated 0.75 mm posterior to the limbus. Mean preoperative CDVA was logMAR 1.17 (Snellen 20/297), and mean postoperative CDVA was logMAR 0.37 (Snellen 20/47) ( p
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Sutureless scleral Fixation of intraocular lenses: outcomes of two approaches. The 2014 Yasuo Tano Memorial Lecture
Graefe's Archive for Clinical and Experimental Ophthalmology, 2015Co-Authors: Ashkan M. Abbey, Rehan M. Hussain, Ankoor R. Shah, Lisa J. Faia, Jeremy D. Wolfe, George A. WilliamsAbstract:Purpose We sought to assess the clinical outcomes and complications of two approaches to scleral Fixation of intraocular lenses (IOLs): transconjunctival Fixation through trocar cannulas and Fixation using scleral tunnels created with a microvitreoretinal (MVR) blade. Methods This retrospective chart review was comprised of 23 eyes that received scleral Fixation of a three-piece IOL with concurrent pars plana vitrectomy between June 2012 and June 2014. Scleral Fixation was performed either by transconjunctival Fixation through trocar cannulas (cannula Fixation) or by the creation of scleral tunnels using an MVR blade (tunnel Fixation). The preoperative and postoperative corrected distance visual acuities (CDVA), spherical equivalents (SE), and complications were evaluated. Results 15 cannula Fixations and 8 tunnel Fixations were performed. Mean follow-up was 353 days (Range: 94 – 790 days). Fifteen IOLs were fixated 2 mm posterior to the limbus. Seven IOLs were fixated 1.5 mm posterior to the limbus, and one IOL was fixated 0.75 mm posterior to the limbus. Mean preoperative CDVA was logMAR 1.17 (Snellen 20/297), and mean postoperative CDVA was logMAR 0.37 (Snellen 20/47) ( p
