Quantitative Approach for the Analysis of Fusional Convergence Using Eye-Tracking and SacLab Toolbox

Fusional vergence is a disjunctive movement of the eyes that is made in order to obtain single vision. (e aim of the study was to provide a quantitative and objective approach for analyzing the fusional convergence response using eye tracking (ET) technology and automatic data analysis provided by the intuitive SacLab toolbox previously developed by our group. We evaluated the proposed approach in a population of 26 subjects with normal binocular vision, who were tested with base-out prisms (magnitudes 4\u394, 6\u394, and 10\u394) in order to elicit fusional convergence response. Eye movements were recorded using the Viewpoint ET and analyzed using SacLab. Parameters describing both the vergence and the version components of the fusional response (convergence duration, CD; peak convergence velocity, PCV; number of intrusive saccades, NS; and mean saccadic amplitude, MSA) were automatically calculated and provided to clinicians for an objective evaluation. Results showed that the number of subjects achieving fusional convergence decreased with prism magnitude. For subjects achieving fusion CD and PCV increased significantly (p < 0.05) when increasing the prism magnitude. For NS and MSA, there were no significant changes when passing to 6\u394, but a significant increase resulted when passing to 10\u394 (p < 0.05). Noninvasive ET associated with the intuitive SacLab toolbox may represent a valid option to objectively characterize the fusional vergence response in clinical setting. (e analysis may be extended to patients with vergence disorders

Population Dynamics of Native Parasitoids Associated with the Asian Chestnut Gall Wasp (Dryocosmus kuriphilus)

Native parasitoids may play an important role in biological control. They may either support or hinder the effectiveness of introduced nonnative parasitoids released for pest control purposes. Results of a three-year survey (2011–2013) of the Asian chestnut gall wasp (ACGW) Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae) populations and on parasitism rates by native indigenous parasitoids (a complex of chalcidoid hymenopterans) in Italian chestnut forests are given. Changes in D. kuriphilus gall size and phenology were observed through the three years of study. A total of 13 species of native parasitoids were recorded, accounting for fluctuating parasitism rates. This variability in parasitism rates over the three years was mainly due to the effect of Torymus flavipes (Walker) (Hymenoptera: Torymidae), which in 2011 accounted for 75% of all parasitoid specimens yet decreased drastically in the following years. This strong fluctuation may be related to climatic conditions. Besides, our data verified that parasitoids do not choose host galls based on their size, though when they do parasitize smaller ones, they exploit them better. Consequently, ACGWs have higher chances of surviving parasitism if they are inside larger galls

SacLab: A toolbox for saccade analysis to increase usability of eye tracking systems in clinical ophthalmology practice

Purpose Many open source software packages have been recently developed to expand the usability of eye tracking systems to study oculomotor behavior, but none of these is specifically designed to encompass all the main functions required for creating eye tracking tests and for providing the automatic analysis of saccadic eye movements. The aim of this study is to introduce SacLab, an intuitive, freely-available MATLAB toolbox based on Graphical User Interfaces (GUIs) that we have developed to increase the usability of the ViewPoint EyeTracker (Arrington Research, Scottsdale, AZ, USA) in clinical ophthalmology practice. Methods SacLab consists of four processing modules that enable the user to easily create visual stimuli tests (Test Designer), record saccadic eye movements (Data Recorder), analyze the recorded data to automatically extract saccadic parameters of clinical interest (Data Analyzer) and provide an aggregate analysis from multiple eye movements recordings (Saccade Analyzer), without requiring any programming effort by the user. Results A demo application of SacLab to carry out eye tracking tests for the analysis of horizontal saccades was reported. We tested the usability of SacLab toolbox with three ophthalmologists who had no programming experience; the ophthalmologists were briefly trained in the use of SacLab GUIs and were asked to perform the demo application. The toolbox gained an enthusiastic feedback from all the clinicians in terms of intuitiveness, ease of use and flexibility. Test creation and data processing were accomplished in 52±21 s and 46±19 s, respectively, using the SacLab GUIs. Conclusions SacLab may represent a useful tool to ease the application of the ViewPoint EyeTracker system in clinical routine in ophthalmology

Gaze Trajectory Index (GTI): A novel metric to quantify saccade trajectory deviation using eye tracking

Background: Many different indexes have been proposed to quantify saccade curvature based on geometric properties of the saccade trajectory projected on the 2D plane. We introduce the Gaze Trajectory Index (GTI), a novel metric to quantify saccade trajectory deviation based on calculation of the rotational eye movements performed in 3D space while following a 2D saccade trajectory recorded with eye tracking (ET). Methods: We provided a description of GTI calculation. In 13 subjects with normal binocular vision we assessed GTI in single-target tests, then we evaluated GTI against previously proposed metrics (Maximum Deviation,MD; Area Curvature,AC; Quadratic Curvature,QC; Initial Direction,ID) using a distractor paradigm that elicited two types of saccade deviations, i.e.\u201cinner-curved\u201d and \u201couter-curved\u201d saccades. Results: In single-target tests GTI showed that saccade curvature was significantly higher for oblique than for vertical saccades (0.86\ub0\ub10.32 vs 0.55\ub0\ub10.60,p < 0.05) and higher for vertical than for horizontal saccades (0.55\ub0\ub10.60 vs 0.23\ub0\ub10.17,p < 0.05), in accordance with previous studies. In distractor-based tests, for inner-curved saccades, GTI strongly correlated with MD (r = 0.965,p < 0.01), AC (r = 0.940,p < 0.01), QC (r = 0.866,p < 0.01), and Principal Component Analysis (PCA) confirmed that all these metrics reflect the same underlying phenomenon. For outer-curved trajectories, GTI showed poor correlation with MD and AC (r = 0.291 and 0.416,p < 0.01), however PCA included the three metrics in the same first component group. For outer-curved trajectories, GTI was the only metric showing strong correlation (r = 0.950,p < 0.05) with the overshoot degree of the trajectory. Conclusion: The novel GTI seems to have adjunctive potential, particularly for outer-curved trajectories, in the estimation of the absolute amount of saccade trajectory deviation

Characterization of Vessel Deformations During EVAR: A Preliminary Retrospective Analysis to Improve Fidelity of Endovascular Simulators

Objective: During endovascular aneurysm repair (EVAR), vessel deformations occur due to the insertion of tools and deployment of stent grafts in the arteries. We present a method for the characterization of vessel deformations during EVAR, and its application on patient datasets for a preliminary retrospective analysis that may be used to improve fidelity of endovascular simulators. Design: The method provides the extraction of vessel profiles from intraoperative fluoroscopic images and the calculation of a tortuosity index in the 2D fluoroscopy view (\ucf\u842D) used to quantify the vessel deformations (\uce\ub4%) during EVAR caused by the stiff guidewire insertion (\uce\ub4%Stiff) and the stent graft deployment (\uce\ub4%Graft), when compared with the undeformed vessel configuration (no device inserted). We applied the method to analyze retrospectively 7 EVAR patient datasets, including vasculature anatomies with different grades of vessel tortuosity or calcification: 2 patients (Pts) with absent tortuosity and mild calcification, 2 with mild tortuosity and mild calcification, 2 with severe tortuosity and mild calcification, and 1 with severe tortuosity and severe calcification. The analysis was focused on deformations of the left common iliac artery (LCIA), which is one of the arterial segments most affected by deformations. Results: In patients with mild LCIA calcification, the vessel straightening effect due to the stiff guidewire insertion increases as the severity of LCIA tortuosity increases (\uce\ub4%Stiff= 0 \uc2\ub1 2%, -19 \uc2\ub1 2%, -45 \uc2\ub1 2% for absent, mild, and severe tortuosity, respectively). In patients with mild/severe LCIA tortuosity, the artery with the deployed graft seems to retain part of the straightening effect caused by the stiff guidewire (\uce\ub4%Graft= -9 \uc2\ub1 3%, -31 \uc2\ub1 2%, for mild and severe tortuosity, respectively). In case of severe LCIA calcification, the stiff guidewire causes only a slight straightening effect (\uce\ub4%Stiff= -12%) despite the severe vessel tortuosity. Conclusion: The method was effective in characterizing real vessel deformations during EVAR. Results gave evidence of a relationship between the obtained deformations and the anatomical vessel conformation. These results may be useful to drive predictive models of vessel deformations during EVAR to be implemented in endovascular patient. -specific simulators for improving their fidelity

Influence of textured backgrounds on fusional vergence: preliminary results using an eye tracker

Purpose: The vergences ensure and maintain binocular fixation and binocular vision. The amplitude of vergences depends on many factors, one of which is the amount of fusible material on the binocular field of vision. In casual seeing the whole surface of the two retinas is exposed to similar stimuli and the conditions for motor fusion should be optimal. The retinal periphery is a powerful factor in production of fusional movements and makes an important contribution to stabilization of relative position of the eyes. The purpose of the study was to evaluate whether the presence of a textured background in the visual stimulus may influence the convergence fusional response. Methods: Eleven subjects with normal binocular vision underwent fusional disparity stimuli: a base-out prism of 6 diopters was placed in front of the right eye to elicit disparity. Eye movements were continuously recorded using the Viewpoint infrared video eye tracker (Arrington Research, Scottsdale, AZ, USA) and a custom software was developed to automatically analyze off-line the saccadic response (gaze angle). Each subject was examined twice, once by presenting the visual stimulus (black dot) on a white background, then by presenting the same stimulus on a textured background (Figure 1). The order of presentation of the two tests was randomly chosen. Results: Eye tracking recordings showed a typical pattern for the fusional behavior: a preliminary saccadic movement of both eyes (version phase) and a following convergence movement with the eyes moving towards each other to achieve single vision (vergence phase) (Figure 2.a). When presenting the stimulus on the white background only 6 subjects (54%) achieved fusional convergence. This number increased up to 9 subjects (82%) when presenting the same stimulus on the textured background (Figure 2.b). Conclusions: The fusional vergence response can be accurately studied and evaluated using an eye tracker. In subjects with normal binocular vision the presence of a textured background seems to facilitate the fusional convergence ability

Cardiac screening prior to return to play after SARS-CoV-2 infection: focus on the child and adolescent athlete: A Clinical Consensus Statement of the Task Force for Childhood Health of the European Association of Preventive Cardiology

Cardiac sequelae after COVID-19 have been described in athletes, prompting the need to establish a return-to-play (RTP) protocol to guarantee a safe return to sports practice. Sports participation is strongly associated with multiple short- and long-term health benefits in children and adolescents and plays a crucial role in counteracting the psychological and physical effects of the current pandemic. Therefore, RTP protocols should be balanced to promote safe sports practice, particularly after an asymptomatic SARS-CoV-2 infection that represents the common manifestation in children. The present consensus document aims to summarize the current evidence on the cardiac sequelae of COVID-19 in children and young athletes, providing key messages for conducting the RTP protocol in paediatric athletes to promote a safe sports practice during the COVID-19 era