Fixation Location Research Articles

Saliency models perform best for women’s and young adults' fixations

Saliency models seek to predict fixation locations in (human) gaze behaviour. These are typically created to generalize across a wide range of visual scenes but validated using only a few participants. Generalizations across individuals are generally implied. We tested this implied generalization across people, not images, with gaze data of 1600 participants. Using a single, feature-rich image, we found shortcomings in the prediction of fixations across this diverse sample. Models performed optimally for women and participants aged 18-29. Furthermore, model predictions differed in performance from earlier to later fixations. Our findings show that gaze behavior towards low-level visual input varies across participants and reflects dynamic underlying processes. We conclude that modeling and understanding gaze behavior will require an approach which incorporates differences in gaze behavior across participants and fixations; validates generalizability; and has a critical eye to potential biases in training- and testing data.

A preference to look closer to the eyes is associated with a position-invariant face neural code

When looking at faces, humans invariably move their eyes to a consistent preferred first fixation location on the face. While most people have the preferred fixation location just below the eyes, a minority have it between the nose-tip and mouth. Not much is known about whether these long-term differences in the preferred fixation location are associated with distinct neural representations of faces. To study this, we used a gaze-contingent face adaptation aftereffect paradigm to test in two groups of observers, one with their mean preferred fixation location closer to the eyes (upper lookers) and the other closer to the mouth (lower lookers). In this task, participants were required to maintain their gaze at either their own group’s mean preferred fixation location or that of the other group during adaptation and testing. The two possible fixation locations were 3.6° apart on the face. We measured the face adaptation aftereffects when the adaptation and testing happened while participants maintained fixation at either the same or different locations on the face. Both groups showed equally strong adaptation effects when the adaptation and testing happened at the same fixation location. Crucially, only the upper lookers showed a partial transfer of the FAE across the two fixation locations, when adaptation occurred at the eyes. Lower lookers showed no spatial transfer of the FAE irrespective of the adaptation position. Given the classic finding that neural tuning is increasingly position invariant as one moves higher in the visual hierarchy, this result suggests that differences in the preferred fixation location are associated with distinct neural representations of faces.

Subclinical Upper Eyelid Ptosis in Asian Patients: The Role of Levator Advancement in Optimizing Outcomes in “Cosmetic” Upper Blepharoplasty

BackgroundSubclinical ptosis is prevalent in Asian patients presenting for aesthetic upper blepharoplasty. To achieve predictable and satisfactory results in these patients, addressing the ptosis component is critical. In this paper, we present a precision levator advancement technique that enabled us to predictably incorporate the levator advancement into our upper blepharoplasty to deliver more predictable results in these patients.Materials and MethodsAsian patients with normal or near normal margin to reflex distance 1 (MRD 1 of ≥ 3.5 mm) and symptoms and signs of straining of the frontalis with eyelid opening were diagnosed with subclinical upper eyelid ptosis and included in this prospective study. The advancement required was estimated pre-operatively using a formula that we developed. Our surgical technique is presented in detail here, and our long-term results were analysed.ResultsFrom December 2019 to August 2022, 97 patients were included in this study. Sixty-five patients were primary cases and 32 were revision cases. The mean follow-up was 15 months. Of the 192 eyelids analysed, our formula was able to correctly identify the required fixation location in 69% of eyelids. In majority of the eyelids (94%), the correct location of fixation location within +/− 1 mm of the estimated location. All patients (100%) were satisfied with their long-term results. Our revision rate was 3%.ConclusionsIncorporating a precisely done levator advancement into the upper blepharoplasty in patients with subclinical ptosis is critical for optimizing the aesthetic and functional outcomes. This approach has enabled us to perform this procedure greater predictably in this group of patients.Level of Evidence III This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Mass-univariate analysis of scalp ERPs reveals large effects of gaze fixation location during face processing that only weakly interact with face emotional expression

Decoding others’ facial expressions is critical for social functioning. To clarify the neural correlates of expression perception depending on where we look on the face, three combined gaze-contingent ERP experiments were analyzed using robust mass-univariate statistics. Regardless of task, fixation location impacted face processing from 50 to 350 ms, maximally around 120 ms, reflecting retinotopic mapping around C2 and P1 components. Fixation location also impacted majorly the N170-P2 interval while weak effects were seen at the face-sensitive N170 peak. Results question the widespread assumption that faces are processed holistically into an indecomposable perceptual whole around the N170. Rather, face processing is a complex and view-dependent process that continues well beyond the N170. Expression and fixation location interacted weakly during the P1-N170 interval, supporting a role for the mouth and left eye in fearful and happy expression decoding. Expression effects were weakest at the N170 peak but strongest around P2, especially for fear, reflecting task-independent affective processing. Results suggest N170 reflects a transition between processes rather than the maximum of a holistic face processing stage. Focus on this peak should be replaced by data-driven analyses of the epoch using robust statistics to fully unravel the early visual processing of faces and their affective content.

Upper cervical spine bone mineral content variations in elderly females

The purpose of the study was to determine the bone mineral densities (BMDs) of the C1 and C2 vertebrae and discuss their implications for autonomous vehicle environments and vulnerable road users. Using quantitated computed tomography (QCT), the BMDs were obtained at eight regions for the C1 vertebra and seven regions for the C2 vertebra. The spine surgeon author outlined the boundaries of each region, and nine elderly female human cadaver specimens were used. The regions were based on potential stabilization locations for fracture fixation. In the C1 vertebra, the BMD was greatest at the anterior tubercle, followed by the posterior tubercle, the posterior arch, and the lateral and anterior lateral masses. In the C2 vertebra, the distal odontoid had the greatest BMD, followed by the spinous process, the C2-lateral mass, the odontoid-body interface, and the anterior inferior aspect of the body. Use of these data in female-specific finite element models may lead to a better understanding of load paths, injuries, mechanisms, and tolerance.

Efficient versus inefficient visual search as training for saccadic re-referencing to an extrafoveal location.

Central vision loss is one of the leading causes of visual impairment in the elderly and its frequency is increasing. Without formal training, patients adopt an unaffected region of the retina as a new fixation location, a preferred retinal locus (PRL). However, learning to use the PRL as a reference location for saccades, that is, saccadic re-referencing, is protracted and time-consuming. Recent studies showed that training with visual search tasks can expedite this process. However, visual search can be driven by salient external features - leading to efficient search, or by internal goals, usually leading to inefficient, attention-demanding search. We compared saccadic re-referencing training in the presence of a simulated central scotoma with either an efficient or an inefficient visual search task. Participants had to respond by fixating the target with an experimenter-defined retinal location in the lower visual field. We observed that comparable relative training gains were obtained in both tasks for a number of behavioral parameters, with higher training gains for the trained task, compared to the untrained task. The transfer to the untrained task was only observed for some parameters. Our findings thus confirm and extend previous research showing comparable efficiency for exogenously and endogenously driven visual search tasks for saccadic re-referencing training. Our results also show that transfer of training gains to related tasks may be limited and needs to be tested for saccadic re-referencing-training paradigms to assess its suitability as a training tool for patients.

Seeing does not mean processing: where we look and the visual information we rely on change independently as we learn a novel walking task.

People use vision to inform motor control strategies during walking. With practice performing a target stepping task, people shift their gaze farther ahead, transitioning from watching their feet contact the target to looking for future target locations. The shift in gaze focus suggests the role of vision in motor control changes from emphasizing feedback to feedforward control. The present study examines whether changing visual fixation location is accompanied by a similar change in reliance upon visual information. Twenty healthy young adults practiced stepping on moving targets projected on the surface of a treadmill. Periodically, participants' visual reliance was probed by hiding stepping targets which inform feedback or feedforward (targets < or > 1.5 steps ahead, respectively) motor control strategies. We calculated visual reliance as the increase in step error when targets were hidden. We hypothesized that with practice, participant reliance on feedback visual information would decrease and their reliance on feedforward visual information would increase. Contrary to our hypothesis, participants became significantly more reliant on feedback visual information with practice (p < 0.001) but their reliance on feedforward visual information did not change (p = 0.49). Participants' reliance on visual information increased despite looking significantly farther ahead with practice (p < 0.016). Together, these results suggest that participants fixated on feedback information less. However, changes in fixation pattern did not reduce their reliance upon feedback information as stepping performance still significantly decreased when feedback information was removed after training. These findings provide important context for how the role of vision in controlling walking changes with practice.

Joint effects of individual reading skills and word properties on Chinese children’s eye movements during sentence reading

Word recognition during the reading of continuous text has received much attention. While a large body of research has investigated how linguistic properties of words affect eye movements during reading, it remains to be established how individual differences in reading skills affect momentary cognitive processes during sentence reading among typically developing Chinese readers. The present study set out to test the joint influences of word properties and individual reading skills on eye movements during reading among Chinese children. We recorded eye movements of 30 grade 3 (G3) children and 27 grade 5 (G5) children when they read sentences silently for comprehension. Predictors of linear mixed models included word frequency, visual complexity, and launch site distance, in addition to the participants’ offline psychometric performances in rapid naming, morphological awareness, word segmenting, and character recognition. The results showed that word properties affected word recognition during sentence reading in both G3 and G5 children. Moreover, word segmenting predicted the G3 children’s fixation durations and the G5 children’s fixation location, whereas rapid naming predicted the G5 children’s fixation duration. Implications are discussed based on the current findings, in light of how different literacy skills contribute to reading development.

Gaze differences in configural and elemental evaluation during multi-attribute decision-making.

While many everyday choices are between multi-attribute options, how attribute values are integrated to allow such choices remains unclear. Recent findings suggest a distinction between elemental (attribute-by-attribute) and configural (holistic) evaluation of multi-attribute options, with different neural substrates. Here, we asked if there are behavioral or gaze pattern differences between these putatively distinct modes of multi-attribute decision-making. Thirty-nine healthy men and women learned the monetary values of novel multi-attribute pseudo-objects (fribbles) and then made choices between pairs of these objects while eye movements were tracked. Value was associated with individual attributes in the elemental condition, and with unique combinations of attributes in the configural condition. Choice, reaction time, gaze fixation time on options and individual attributes, and within- and between-option gaze transitions were recorded. There were systematic behavioral differences between elemental and configural conditions. Elemental trials had longer reaction times and more between-option transitions, while configural trials had more within-option transitions. The effect of last fixation on choice was more pronounced in the configural condition. We observed differences in gaze patterns and the influence of last fixation location on choice in multi-attribute value-based choices depending on how value is associated with those attributes. This adds support for the claim that multi-attribute option values may emerge either elementally or holistically, reminiscent of similar distinctions in multi-attribute object recognition. This may be important to consider in neuroeconomics research that involve visually-presented complex objects.

Clinical Insights into the Treatment of Patellofemoral Instability with Medial Patellofemoral Ligament Reconstruction: Pearls and Pitfalls-Lessons Learned from 20 Years.

Patellofemoral instability is a prevalent cause of pain and disability in young individuals engaged in athletic activities. Adolescents face a particularly notable risk of patellar dislocation, which can be attributed to rapid skeletal growth, changes in q-angle, ligamentous laxity, higher activity levels, and increased exposure to risk. Specific sports activities carry an elevated risk of patellar dislocation. Younger age and trochlear dysplasia present the highest risk factors for recurrent patellar dislocations. International guidelines recommend conservative therapy following a single patellar dislocation without osteochondral lesions but suggest surgical intervention in recurrent cases. In this study, we have compiled current scientific data on therapy recommendations, focusing on MPFL (medial patellofemoral ligament) reconstruction. We discuss patient selection, surgical indications, graft selection, location and choice of fixation, graft tensioning, and postoperative care.

Effects of Age and Fixation Location on Face Identification

Effects of Age and Fixation Location on Face Identification

Anatomic, histologic, and mechanical features of the right atrium: implications for leadless atrial pacemaker implantation.

Leadless pacemakers (LPs) may mitigate the risk of lead failure and pocket infection related to conventional transvenous pacemakers. Atrial LPs are currently being investigated. However, the optimal and safest implant site is not known. We aimed to evaluate the right atrial (RA) anatomy and the adjacent structures using complementary analytic models [gross anatomy, cardiac magnetic resonance imaging (MRI), and computer simulation], to identify the optimal safest location to implant an atrial LP human. Wall thickness and anatomic relationships of the RA were studied in 45 formalin-preserved human hearts. In vivo RA anatomy was assessed in 100 cardiac MRI scans. Finally, 3D collision modelling was undertaken assessing for mechanical device interaction. Three potential locations for an atrial LP were identified; the right atrial appendage (RAA) base, apex, and RA lateral wall. The RAA base had a wall thickness of 2.7 ± 1.6 mm, with a low incidence of collision in virtual implants. The anteromedial recess of the RAA apex had a wall thickness of only 1.3 ± 0.4 mm and minimal interaction in the collision modelling. The RA lateral wall thickness was 2.6 ± 0.9 mm but is in close proximity to the phrenic nerve and sinoatrial artery. Based on anatomical review and 3D modelling, the best compromise for an atrial LP implantation may be the RAA base (low incidence of collision, relatively thick myocardial tissue, and without proximity to relevant epicardial structures); the anteromedial recess of the RAA apex and lateral wall are alternate sites. The mid-RAA, RA/superior vena cava junction, and septum appear to be sub-optimal fixation locations.

A New Vessel-Based Method to Estimate Automatically the Position of the Nonfunctional Fovea on Altered Retinography From Maculopathies.

The purpose of this study was to validate a new automated method to locate the fovea on normal and pathological fundus images. Compared to the normative anatomic measures (NAMs), our vessel-based fovea localization (VBFL) approach relies on the retina's vessel structure to make predictions. The spatial relationship between the fovea location and vessel characteristics is learnt from healthy fundus images and then used to predict fovea location in new images. We evaluate the VBFL method on three categories of fundus images: healthy images acquired with different head orientations and fixation locations, healthy images with simulated macular lesions, and pathological images from age-related macular degeneration (AMD). For healthy images taken with the head tilted to the side, the NAM estimation error is significantly multiplied by 4, whereas VBFL yields no significant increase, representing a 73% reduction in prediction error. With simulated lesions, VBFL performance decreases significantly as lesion size increases and remains better than NAM until lesion size reaches 200 degrees2. For pathological images, average prediction error was 2.8degrees, with 64% of the images yielding an error of 2.5 degrees or less. VBFL was not robust for images showing darker regions and/or incomplete representation of the optic disk. The vascular structure provides enough information to precisely locate the fovea in fundus images in a way that is robust to head tilt, eccentric fixation location, missing vessels, and actual macular lesions. The VBFL method should allow researchers and clinicians to assess automatically the eccentricity of a newly developed area of fixation in fundus images with macular lesions.

Visual Search Strategies in Badminton Serve : Expertise and Performance(Sucess or Failure) Perspective

PURPOSE The main purpose of this study was to examine the difference in visual search strategies based on the skill level in success and failure cases in badminton short serves.METHODS To this end, six badminton experts (experience: more than 10 years) and six novices (less than 1 years) participated. The participants’ eye movement was recorded during each trial, and mean fixation duration, mean saccade amplitude, percentage of viewing time on each fixation location, final fixation duration, and gaze entropy were analyzed.RESULTS First, the mean fixation duration did not differ significantly, but the mean saccade amplitude increased when expert players failed to perform the serve successfully. Second, the percentage of viewing time on each location results showed that the overall viewing time was lower when the performance was unsuccessful, and the expert players fixated longer time viewing the net and space when they made a successful serve. Third, expert players showed longer QE than novice players when they made a successful serve. Finally, the gaze entropy results showed that expert players showed greater gaze entropy during successful performance, indicating that the gaze pattern was randomly distributed across trials.CONCLUSIONS When learning a badminton serve, we should fully recognize and explore the receiver’s location and external environment, and subsequently, before initiating serve movement, focus on the net or space between the receiver’s racquet and shoulders to make a more successful performance. In addition, we should make various patterns of the visual search strategy, rather than the fixed or consistent search strategy, to deceive receivers.

Upper Eyelid Ptosis Correction with Levator Advancement Using the Levator Musculoaponeurotic Junction Formula in White Patients.

Upper eyelid ptosis correction is a challenging procedure. The authors report a novel approach to this procedure that is more accurate and predictable compared with conventional approaches. A preoperative system of assessment has been formulated to more accurately estimate the amount of levator advancement required. The levator advancement was referenced from a constant landmark: the musculoaponeurotic junction of the levator palpebrae superioris. The factors considered include the amount of upper lid elevation required, the degree of compensatory brow elevation present, and eye dominance. The preoperative assessment and surgical technique are presented in a series of detailed operative videos. The levator advancement is performed as planned preoperatively with final adjustment made intraoperatively to achieve correct lid height and symmetry. Seventy-seven patients (154 eyelids) were analyzed prospectively in this study. The authors found this approach to be reliable and accurate in predicting the required amount of levator advancement. Intraoperatively, the formula correctly predicted the exact required fixation location in 63% of eyelids, and to within ±1 mm in 86% of cases. This may be used for patients with ptosis of varying severity, ranging from mild to severe eyelid ptosis. The revision rate was 4%. This approach is accurate in determining the fixation location needed, enabling levator advancement for ptosis correction to be performed with more precision and predictability. Therapeutic, IV.

Gaze Control and Tactical Decision-Making Under Stress in Active-Duty Police Officers During a Live Use-of-Force Response

Police officers during dynamic and stressful encounters are required to make rapid decisions that rely on effective decision-making, experience, and intuition. Tactical decision-making is influenced by the officer’s capability to recognize critical visual information and estimation of threat. The purpose of the current study is to investigate how visual search patterns using cluster analysis and factors that differentiate expertise (e.g., years of service, tactical training, related experiences) influence tactical decision-making in active-duty police officers (44 active-duty police officers) during high stress, high threat, realistic use of force scenario following a car accident and to examine the relationships between visual search patterns and physiological response (heart rate). A cluster analysis of visual search variables (fixation duration, fixation location difference score, and number of fixations) produced an Efficient Scan and an Inefficient Scan group. Specifically, the Efficient Scan group demonstrated longer total fixation duration and differences in area of interests (AOI) fixation duration compared to the Inefficient Scan group. Despite both groups exhibiting a rise in physiological stress response (HR) throughout the high-stress scenario, the Efficient Scan group had a history of tactical training, improved return fire performance, had higher sleep time total, and demonstrated increased processing efficiency and effective attentional control, due to having a background of increased tactical training.

Outcomes of Biceps Tenodesis Variations With Concomitant Rotator Cuff Repair: A Multicenter Database Analysis.

Studies to date comparing biceps tenodesis methods in the setting of concomitant rotator cuff repair (RCR) have demonstrated relatively equivalent pain and functional outcomes. To compare biceps tenodesis constructs, locations, and techniques in patients who underwent RCR using a large multicenter database. Cohort study; Level of evidence, 3. A global outcome database was queried for patients with medium- and large-sized tears who underwent biceps tenodesis with RCR between 2015 and 2021. Patients ≥18 years of age with a minimum follow-up of 1 year were included. The American Shoulder and Elbow Surgeons, Single Assessment Numeric Evaluation, visual analog scale for pain, and Veterans RAND 12-Item Health Survey (VR-12) scores were compared at 1 and 2 years of follow-up based on construct (anchor, screw, or suture), location (subpectoral, suprapectoral, or top of groove), and technique (inlay or onlay). Nonparametric hypothesis testing was used to compare continuous outcomes at each time point. The proportion of patients achieving the minimal clinically important difference (MCID) at the 1- and 2-year follow-ups were compared between groups using chi-square tests. A total of 1903 unique shoulder entries were analyzed. Improvement in VR-12 Mental score favored anchor and suture fixations at 1 year of follow-up (P = .042) and the onlay tenodesis technique at 2 years of follow-up (P = .029). No additional tenodesis comparisons demonstrated statistical significance. The proportion of patients with improvement exceeding the MCID did not differ based on tenodesis methods for any outcome score assessed at the 1- or 2-year follow-up. Biceps tenodesis with concomitant RCR led to improved outcomes regardless of tenodesis fixation construct, location, or technique. A clear optimal tenodesis method with RCR remains to be determined. Surgeon preference and experience with various tenodesis methods as well as patient clinical presentation should continue to guide surgical decision-making.

Fixation Location and Stability in Best Vitelliform Macular Dystrophy

To analyze fixation location and stability in best vitelliform macular dystrophy (BVMD) and test their association with best-corrected visual acuity (BCVA). Observational, cross-sectional study. Thirty patients (55 eyes) affected by genetically confirmed BVMD were followed up at the Retinal Heredodystrophies Unit of IRCCS San Raffaele Scientific Institute, Milan. Patients underwent testing with macular integrity assessment (MAIA) microperimeter. Fixation location was measured as distance in degrees (°) between preferred retinal locus (PRL) and estimated fovea location (EFL); fixation was defined as eccentric when the distance between PRL and EFL exceeded 2°. Fixation stability was graded as stable, relatively unstable, or unstable and expressed as bivariate contour ellipse area (BCEA, °2). Fixation location and stability. The median distance of the PRL from the anatomic fovea was 0.7°, and fixation location was eccentric in 27% of eyes. Fixation was graded as stable in 64% of eyes, relatively unstable in 13%, and unstable in 24%, with a median 95% BCEA of 6.2°2. The atrophic/fibrotic stage was associated with worse fixation parameters (all P<0.01). Both PRL eccentricity and fixation stability were linearly associated with BCVA: every 1° increase in PRL eccentricity was associated with a 0.07 logarithm of the minimum angle of resolution (logMAR) worse BCVA (P<0.0001) while every 1°2 increase in 95% BCEA was associated with a 0.01 logMAR worse BCVA (P<0.001). No significant intereye correlation was found for PRL eccentricity and fixation stability, as well as no association between the patient's age and fixation parameters. We demonstrated that most eyes affected by BVMD retain a central stable fixation and provided evidence that both fixation eccentricity and stability are strongly associated with visual acuity in BVMD. These parameters may serve as secondary end points for future clinical trials. Proprietary or commercial disclosure may be found after the references.

Medial Patellofemoral Reconstruction Techniques for Patellar Instability

The medial patellofemoral complex (MPFC) is the term used to describe the primary soft tissue stabilizer of the patella, which consists of fibers that attach to the patella (medial patellofemoral ligament, or MPFL), and the quadriceps tendon (medial quadriceps tendon femoral ligament, or MQTFL). Despite the variability of its attachment on the extensor mechanism, the midpoint of this complex is consistently at the junction of the medial quadriceps tendon with the articular surface of the patella, indicating that either patellar or quadriceps tendon fixation can be used for anatomic reconstruction. Multiple techniques exist to reconstruct the MPFC, including graft fixation on the patella, quadriceps tendon, or both structures. Various techniques using several graft types and fixation devices have all reported good outcomes. Regardless of the location of fixation on the extensor mechanism, elements critical to the success of the procedure include anatomic femoral tunnel placement, avoiding placing undue tension on the graft, and addressing concurrent morphological risk factors when present. This infographic reviews the anatomy and techniques for the reconstruction of the MPFC, including graft configuration, type, and fixation, while addressing common pearls and pitfalls in the surgical treatment of patellar instability.

Dyslexia: Causes and Concomitant Impairments.

In recent decades, theories have been presented to explain the nature of dyslexia, but the causes of dyslexia remained unclear. Although the investigation of the causes of dyslexia presupposes a clear understanding of the concept of cause, such an understanding is missing. The present paper proposes the absence of at least one necessary condition or the absence of all sufficient conditions as causes for impaired reading. The causes of impaired reading include: an incorrect fixation location, too short a fixation time, the attempt to recognize too many letters simultaneously, too large saccade amplitudes, and too short verbal reaction times. It is assumed that a longer required fixation time in dyslexic readers results from a functional impairment of areas V1, V2, and V3 that require more time to complete temporal summation. These areas and areas that receive input from them, such as the fusiform gyrus, are assumed to be impaired in their ability to simultaneously process a string of letters. When these impairments are compensated by a new reading strategy, reading ability improves immediately.