Embedding 3-D Gaze Points on a 3-D Visual Field: A Case of Transparency

The paper seeks to demonstrates the likelihood of embedding a 3D gaze point on a 3D visual field, the visual field is inform of a game console where the user has to play from one level to the other by overcoming obstacles that will lead them to the next level. Complex game interface is sometimes difficult for the player to progress to next level of the game and the developers also find it difficult to regulate the game for an average player. The model serves as an analytical tool for game adaptations and also players can track their response to the game. Custom eye tracking and 3D object tracking algorithms were developed to enhance the analysis of the procedure. This is a part of the contributions to user interface design in the aspect of visual transparency. The development and testing of human computer interaction uses and application is more easily investigated than ever, part of the contribution to this is the embedding of 3-D gaze point on a 3-D visual field. This could be used in a number of applications, for instance in medical applications that includes long and short sightedness diagnosis and treatment. Experiments and Test were conducted on five different episodes of user attributes, result show that fixation points and pupil changes are the two most likely user attributes that contributes most significantly in the performance of the custom eye tracking algorithm the study. As the advancement in development of eye movement algorithm continues user attributes that showed the least likely appearance will prove to be redundant.

Examining Gaze Cone Shape and Size

Another person's looking behavior is used by observers to judge gaze direction and fixation points. An important task in this context is the judgement of direct gaze, that is, the perception of being looked at. The cone of gaze can be defined as the range of fixation points that support direct gaze. The cone concept implies that this range lawfully increases with distance, but that the cone angle is constant. The present experiment tested the concept with a larger number and a more extended range of distances than previously done, and took care of possible directional errors. The gaze cone was found to be roughly linear, and stable between 1.6 m and 7.9 m – an almost perfect cone. The mean cone size subtended 5.2° in diameter when averaged over ascending and descending series. Measures differed, however, in ascending and descending series, consistent with a conservative bias. Also, the variability of judgements increased slightly with distance. Results are discussed considering whether cone size is actually smaller than often reported in the literature.

O04 DETERMINING THE EFFECT OF MESH WIDTH AND FIXATION PATTERNS ON THE STRENGTH OF PROPHYLACTICALLY REINFORCED LAPAROTOMY INCISIONS

Aim Research indicates that prophylactic mesh may help prevent incisional hernia after laparotomy, but best practice patterns in these situations are still evolving. Here, we compare the failure loads (FLs) and biomechanical stiffness (BMS) of 35 porcine abdominal wall laparotomy incisions reinforced with meshes of various widths and fixation distances using biomechanical testing. Material and Methods In each specimen, a ten centimeter (cm) incision was made and closed using continuous 1-0 Maxon suture. Specimens were randomized to mesh width (none, 2.5cm, 3cm, 4cm, 6cm, 8cm) and tack separation (1.5cm, 2cm apart), and the meshes secured in an onlay fashion. Cyclic loads oscillating from 15 Newtons (N) to 140N were applied to stimulate abdominal wall stress, and the specimens subsequently loaded to failure. FLs (N) and BMS (N/mm) were comparatively analyzed. Results All specimens failed via suture pull-through. FLs and BMS were lowest in specimens with suture-only (421.43 N; 11.69 N/mm). FLs and BMS were significantly higher in 4cm mesh specimens (567.51N) than those with suture, 2.5cm, and 3.0cm mesh (all p < 0.05). FLs in specimens with a greater number of tacks were consistently higher in meshes of similar sizes, although these did not reach significance. Conclusions Four cm mesh re-enforcement is superior to suture-only and smaller meshes at preserving strength in laparotomy closure in the early stages of healing, but larger meshes (6cm, 8cm) do not provide additional benefit. Meshes with more fixation points may be advantageous, but additional data is needed to make definitive conclusions.

Acute failure of S2-alar-iliac screw pelvic fixation in adult spinal deformity: novel failure mechanism, case series, and review of the literature

OBJECTIVE Pelvic fixation with S2-alar-iliac (S2AI) screws is an established technique in adult deformity surgery. The authors’ objective was to report the incidence and risk factors for an underreported acute failure mechanism of S2AI screws. METHODS The authors retrospectively reviewed a consecutive series of ambulatory adults with fusions extending 3 or more levels, and which included S2AI screws. Acute failure of S2AI screws was defined as occurring within 6 months of the index surgery and requiring surgical revision. RESULTS Failure occurred in 6 of 125 patients (5%) and consisted of either slippage of the rods or displacement of the set screws from the S2AI tulip head, with resultant kyphotic fracture. All failures occurred within 6 weeks postoperatively. Revision with a minimum of 4 rods connecting to 4 pelvic fixation points was successful. Two of 3 (66%) patients whose revision had less fixation sustained a second failure. Patients who experienced failure were younger (56.5 years vs 65 years, p = 0.03). The magnitude of surgical correction was higher in the failure cohort (number of levels fused, change in lumbar lordosis, change in T1–pelvic angle, and change in coronal C7 vertical axis, each p < 0.05). In the multivariate analysis, younger patient age and change in lumbar lordosis were independently associated with increased failure risk (p < 0.05 for each). There was a trend toward the presence of a transitional S1–2 disc being a risk factor (OR 8.8, 95% CI 0.93–82.6). Failure incidence was the same across implant manufacturers (p = 0.3). CONCLUSIONS All failures involved large-magnitude correction and resulted from stresses that exceeded the failure loads of the set plugs in the S2AI tulip, with resultant rod displacement and kyphotic fractures. Patients with large corrections may benefit from 4 total S2AI screws at the time of the index surgery, particularly if a transitional segment is present. Salvage with a minimum of 4 rods and 4 pelvic fixation points can be successful.

Visual Attention Software: A New Tool for Understanding the “Subliminal” Experience of the Built Environment

Eye-tracking technology is a biometric tool that has found many commercial and research applications. The recent advent of affordable wearable sensors has considerably expanded the range of these possibilities to fields such as computer gaming, education, entertainment, health, neuromarketing, psychology, etc. The Visual Attention Software by 3M (3M-VAS) is an artificial intelligence application that was formulated using experimental data from eye-tracking. It can be used to predict viewer reactions to images, generating fixation point probability maps and fixation point sequence estimations, thus revealing pre-attentive processing of visual stimuli with a very high degree of accuracy. We have used 3M-VAS software in an innovative implementation to analyze images of different buildings, either in their original state or photographically manipulated, as well as various geometric patterns. The software not only reveals non-obvious fixation points, but also overall relative design coherence, a key element of Christopher Alexander’s theory of geometrical order. A more evenly distributed field of attention seen in some structures contrasts with other buildings being ignored, those showing instead unconnected points of splintered attention. Our findings are non-intuitive and surprising. We link these results to both Alexander’s theory and Neuroscience, identify potential pitfalls in the software’s use, and also suggest ways to avoid them.

Computer-aided autism diagnosis based on visual attention models using eye tracking

An advantage of using eye tracking for diagnosis is that it is non-invasive and can be performed in individuals with different functional levels and ages. Computer/aided diagnosis using eye tracking data is commonly based on eye fixation points in some regions of interest (ROI) in an image. However, besides the need for every ROI demarcation in each image or video frame used in the experiment, the diversity of visual features contained in each ROI may compromise the characterization of visual attention in each group (case or control) and consequent diagnosis accuracy. Although some approaches use eye tracking signals for aiding diagnosis, it is still a challenge to identify frames of interest when videos are used as stimuli and to select relevant characteristics extracted from the videos. This is mainly observed in applications for autism spectrum disorder (ASD) diagnosis. To address these issues, the present paper proposes: (1) a computational method, integrating concepts of Visual Attention Model, Image Processing and Artificial Intelligence techniques for learning a model for each group (case and control) using eye tracking data, and (2) a supervised classifier that, using the learned models, performs the diagnosis. Although this approach is not disorder-specific, it was tested in the context of ASD diagnosis, obtaining an average of precision, recall and specificity of 90%, 69% and 93%, respectively.

A low-cost, high-performance video-based binocular eye tracker for psychophysical research

We describe a high-performance, pupil-based binocular eye tracker that approaches the performance of a well-established commercial system, but at a fraction of the cost. The eye tracker is built from standard hardware components, and its software (written in Visual C++) can be easily implemented. Because of its fast and simple linear calibration scheme, the eye tracker performs best in the central 10 degrees of the visual field. The eye tracker possesses a number of useful features: (1) automated calibration simultaneously in both eyes while subjects fixate four fixation points sequentially on a computer screen, (2) automated real-time continuous analysis of measurement noise, (3) automated blink detection, (4) and real-time analysis of pupil centration artifacts. This last feature is critical because it is known that pupil diameter changes can be erroneously registered by pupil-based trackers as a change in eye position. We evaluated the performance of our system against that of a well-established commercial system using simultaneous measurements in 10 participants. We propose our low-cost eye tracker as a promising resource for studies of binocular eye movements.

Challenge of diagnosing splenic torsion in a paediatric patient with gastroschisis

Gastroschisis is an uncommon congenital defect of the abdominal wall resulting in intestinal prolapse, most commonly associated with short gut syndrome or bowel obstruction. Wandering spleen, movement of the spleen due to the underdevelopment of splenic ligaments, has a prevalence of 0.25% and is asymptomatic in 15% of paediatric cases. An 11-year-old patient, admitted with a history of gastroschisis repaired at birth, presents with 18 months of intermittent, worsening abdominal pain. Imaging demonstrated splenomegaly and tortuosity of the splenic vein with abnormal positioning of the superior mesenteric artery and vein. The patient was found to have a wandering spleen with subacute splenic infarct secondary to splenic torsion, necessitating emergent surgical intervention. This patient experienced an extremely rare complication of gastroschisis that has not previously been reported. This complication is caused by a lack of appropriate abdominal fixation points for the spleen.

Reper intraocular lens with artificial iris: implantation techniques and outcomes

The authors describe the surgical techniques to implant a novel intraocular lens with artificial iris (Reper) in patients affected by traumatic aphakia and aniridia. Two surgical approaches are proposed: implantation by suture-loaded cartridge and “open sky” implantation combined with penetrating keratoplasty. The method of establishing the exact position of the scleral fixation points and the pre-assembly of the suture of Reper before its implantation are the main novel proposed surgical procedures. The rationale is to minimize surgical procedures in the anterior chamber and to prevent knot loosening and lens tilting. The simultaneous treatment of aphakia and aniridia with a single prosthesis, the stability of the Reper and the functional, anatomical and aesthetic outcomes obtained are the highlighted advantages in this study.