Visual Field Size Research Articles

Wide-angle simulated artificial vision enhances spatial navigation and object interaction in a naturalistic environment

Objective. Vision restoration approaches, such as prosthetics and optogenetics, provide visual perception to blind individuals in clinical settings. Yet their effectiveness in daily life remains a challenge. Stereotyped quantitative tests used in clinical trials often fail to translate into practical, everyday applications. On the one hand, assessing real-life benefits during clinical trials is complicated by environmental complexity, reproducibility issues, and safety concerns. On the other hand, predicting behavioral benefits of restorative therapies in naturalistic environments may be a crucial step before starting clinical trials to minimize patient discomfort and unmet expectations.Approach. To address this, we leverage advancements in virtual reality technology to conduct a fully immersive and ecologically valid task within a physical artificial street environment. As a case study, we assess the impact of the visual field size in simulated artificial vision for common outdoor tasks.Main results. We show that a wide visual angle (45°) enhances participants' ability to navigate and solve tasks more effectively, safely, and efficiently. Moreover, it promotes their learning and generalization capability. Concurrently, it changes the visual exploration behavior and facilitates a more accurate mental representation of the environment. Further increasing the visual angle beyond this value does not yield significant additional improvements in most metrics.Significance. We present a methodology combining augmented reality with a naturalistic environment, enabling participants to perceive the world as patients with retinal implants would and to interact physically with it. Combining augmented reality in naturalistic environments is a valuable framework for low vision and vision restoration research.

Knowing me, knowing you-A study on top-down requirements for compensatory scanning in drivers with homonymous visual field loss.

It is currently still unknown why some drivers with visual field loss can compensate well for their visual impairment while others adopt ineffective strategies. This paper contributes to the methodological investigation of the associated top-down mechanisms and aims at validating a theoretical model on the requirements for successful compensation among drivers with homonymous visual field loss. A driving simulator study was conducted with eight participants with homonymous visual field loss and eight participants with normal vision. Participants drove through an urban surrounding and experienced a baseline scenario and scenarios with visual precursors indicating increased likelihoods of crossing hazards. Novel measures for the assessment of the mental model of their visual abilities, the mental model of the driving scene and the perceived attention demand were developed and used to investigate the top-down mechanisms behind attention allocation and hazard avoidance. Participants with an overestimation of their visual field size tended to prioritize their seeing side over their blind side both in subjective and objective measures. The mental model of the driving scene showed close relations to the subjective and actual attention allocation. While participants with homonymous visual field loss were less anticipatory in their usage of the visual precursors and showed poorer performances compared to participants with normal vision, the results indicate a stronger reliance on top-down mechanism for drivers with visual impairments. A subjective focus on the seeing side or on near peripheries more frequently led to bad performances in terms of collisions with crossing cyclists. The study yielded promising indicators for the potential of novel measures to elucidate top-down mechanisms in drivers with homonymous visual field loss. Furthermore, the results largely support the model of requirements for successful compensatory scanning. The findings highlight the importance of individualized interventions and driver assistance systems tailored to address these mechanisms.

The Impact of Visual Field Size on Eye-Head Coordination During Cognitive Processing

The Impact of Visual Field Size on Eye-Head Coordination During Cognitive Processing

Placebo effect after visual restitution training: no eye-tracking controlled perimetric improvement after visual border stimulation in late subacute and chronic visual field defects after stroke.

A significant number of Restitution Training (RT) paradigms claim to ameliorate visual field loss after stroke by re-activating neuronal connections in the residual visual cortex due to repeated bright light-stimulation at the border of the blind and intact fields. However, the effectiveness of RT has been considered controversial both in science and clinical practice for years. The main points of the controversy are (1) the reliability of perimetric results which may be affected by compensatory eye movements and (2) heterogeneous samples consisting of patients with visual field defects and/or visuospatial neglect. By means of our newly developed and validated Virtual Reality goggles Salzburg Visual Field Trainer (SVFT) 16 stroke patients performed RT on a regular basis for 5 months. By means of our newly developed and validated Eye Tracking Based Visual Field Analysis (EFA), we conducted a first-time full eye-movement-controlled perimetric pre-post intervention study. Additionally, patients subjectively rated the size of their intact visual field. Analysis showed that patients' mean self-assessment of their subjective visual field size indicated statistically significant improvement while, in contrast, objective eye tracking controlled perimetric results revealed no statistically significant effect. Bright-light detection RT at the blind-field border solely induced a placebo effect and did not lead to training-induced neuroplasticity in the visual cortex of the type needed to ameliorate the visual field size of stroke patients.

Evaluation of Sleep Quality and Fatigue in Patients with Usher Syndrome Type 2a

To study the prevalence, level, and nature of sleep problems and fatigue experienced by Usher syndrome type 2a (USH2a) patients. Cross-sectional study. Fifty-six genetically confirmed Dutch patients with syndromic USH2a and 120 healthy controls. Sleep quality, prevalence, and type of sleep disorders, chronotype, fatigue, and daytime sleepiness were assessed using 5 questionnaires: (1) Pittsburgh Sleep Quality Index, (2) Holland Sleep Disorders Questionnaire, (3) Morningness-Eveningness Questionnaire, (4) Checklist Individual Strength, and (5) Epworth Sleepiness Scale. For a subset of patients, recent data on visual function were used to study the potential correlation between the outcomes of the questionnaires and disease progression. Results of all questionnaires were compared between USH2a and control cohorts, and the scores of the patients were compared with disease progression defined by age, visual field size, and visual acuity. Compared with the control population, patients with USH2a experienced a poorer quality of sleep, a higher incidence of sleep disorders, and higher levels of fatigue and daytime sleepiness. Intriguingly, the sleep disturbances and high levels of fatigue were not correlated with the level of visual impairment. These results are in accordance with the patients' experiences that their sleep problems already existed before the onset of vision loss. This study demonstrates a high prevalence of fatigue and poor sleep quality experienced by patients with USH2a. Recognition of sleep problems as a comorbidity of Usher syndrome would be a first step toward improved patient care. The absence of a relationship between the level of visual impairment and the severity of reported sleep problems is suggestive of an extraretinal origin of the sleep disturbances. Proprietary or commercial disclosure may be found after the references.

The role of the visual field size in artificial vision

Objective. Artificial vision has been and still is the subject of intense research. The ultimate goal is to help blind people in their daily life. Approaches to artificial vision, including visual prostheses and optogenetics, have strongly focused on restoring high visual acuity for object recognition and reading. Consequently, clinical trials were primarily focused on these parameters. Approach. Alternatively, enlarging the visual field (VF) size could significantly improve artificial vision. Main results. I propose that approaches towards artificial vision address the challenge of creating this rudimental form of sight within a large VF. Significance. Enlarging the VF size will enable users to improve their mobility and perform visually-driven search tasks. Eventually, it could make artificial vision more efficient, comfortable and acceptable from the user’s point of view.

Evaluating Energy Efficiency and Colorimetric Quality of Electric Light Sources Using Alternative Spectral Sensitivity Functions

Photometric and colorimetric quantities are calculated using spectral luminous efficiency and color matching functions (CMFs), respectively. Past studies highlighted the limitations of the standard sensitivity functions based on visual experiments conducted over a century ago. There have been new alternatives proposed, but the effect of the proposed alternatives functions on energy efficiency, and the colorimetric quality of light sources has rarely been investigated. It is reasonable to assume that updating photometric and colorimetric calculation procedures will make significant impacts on the characterization of electric light sources. Here, the impact of six luminous efficiency functions and six CMFs on luminous efficacy of radiation and chromaticity calculations were analyzed. Results indicate a significant effect of alternative functions on luminous efficacy of radiation (LER), chromaticity coordinates (CIE 1931 x,y and CIE 1976 u′,v′) and Duv. The biggest impact was caused by the change in the visual field of view (2-degree vs. 10-degree observer), highlighting the importance of visual field size for color and luminosity function. Updating the standardized luminous efficiency function may impact the performance characterization of electric light sources, but cost-benefit analysis should be studied to understand the broad impacts.

A new computational model illuminates the extraordinary eyes of Phronima.

Vision in the midwater of the open ocean requires animals to perform visual tasks quite unlike those of any other environment. These tasks consist of detecting small, low contrast objects and point sources against a relatively dim and uniform background. Deep-sea animals have evolved many extraordinary visual adaptations to perform these tasks. Linking eye anatomy to specific selective pressures, however, is challenging, not least because of the many difficulties of studying deep-sea animals. Computational modelling of vision, based on detailed morphological reconstructions of animal eyes, along with underwater optics, offers a chance to understand the specific visual capabilities of individual visual systems. Prior to the work presented here, comprehensive models for apposition compound eyes in the mesopelagic, the dominant eye form of crustaceans, were lacking. We adapted a model developed for single-lens eyes and used it to examine how different parameters affect the model's ability to detect point sources and extended objects. This new model also allowed us to examine spatial summation as a means to improve visual performance. Our results identify a trade-off between increased depth range over which eyes function effectively and increased distance at which extended objects can be detected. This trade-off is driven by the size of the ommatidial acceptance angle. We also show that if neighbouring ommatidia have overlapping receptive fields, spatial summation helps with all detection tasks, including the detection of bioluminescent point sources. By applying our model to the apposition compound eyes of Phronima, a mesopelagic hyperiid amphipod, we show that the specialisations of the large medial eyes of Phronima improve both the detection of point sources and of extended objects. The medial eyes outperformed the lateral eyes at every modelled detection task. We suggest that the small visual field size of Phronima's medial eyes and the strong asymmetry between the medial and lateral eyes reflect Phronima's need for effective vision across a large depth range and its habit of living inside a barrel. The barrel's narrow aperture limits the usefulness of a large visual field and has allowed a strong asymmetry between the medial and lateral eyes. The model provides a useful tool for future investigations into the visual abilities of apposition compound eyes in the deep sea.

No Common Factor Underlying Decline of Visual Abilities in Mild Cognitive Impairment

ABSTRACT Introduction Recent work has shown an association between cognitive and visual impairments and two main theories were advanced, namely the sensory deprivation and the common cause theories. Most studies considered only basic visual functions such as visual acuity or visual field size and evaluated the association with dementia. Objectives To reconcile between these theories and to test the link between visual and cognitive decline in mildly cognitive impaired people. Methods We employed a battery of 19 visual tasks on 39 older adults with mild cognitive impairment and 91 without any evidence of cognitive decline, as measured by the Montreal Cognitive Assessment. Results Our results show a strong association between visual impairment and mild cognitive impairment. In agreement with previous results with younger and healthy older adults, we found also only weak correlations between most tests in older adults with mild cognitive impairment. Conclusion Our results suggest that visual and cognitive abilities decline simultaneously, but they do so independently across visual and cognitive functions and across participants.

Automated Functional Color Field Tester (FCFTester) Trends and Reproducibility – A Multicenter Pilot Study

Background: The present study was designed to assess a protocol for investigating normative trends of kinetic color visual field sizes and reproducibility of such utilizing the Automated Functional Color Field Tester (FCFTester). Methods: The participants were recruited at three clinical sites. The participants were screened for the study based on a questionnaire designed by the authors to help assess the inclusion and exclusion criteria. There were 116 adult-only participants, however, only those reporting White race (n = 106) were used for statistical analysis. The mean age was 35.8 (std = 14) and nearly 70% of the sample was female. Results: This study demonstrated that kinetic visual field sizes across all four color isopters are not influenced by gender (p = 0.96) nor eye tested (p = 0.46). Only a slight difference in mean visual field sizes was found between the three clinical sites ranging from less than 2.5 degrees when the target was blue or green to less than 1.5 degrees for white or red targets. Overall, age had limited, yet significant, influence on kinetic field sizes likely related to the relatively young age of our participants. A significant difference in mean field size existed when comparing the four color isopters with an ascending order of green, red, blue, and white. This pattern was consistent across the three testing sites. Variability in field size for each color isopter was slight across the three clinical sites. Conclusion: The present pilot study shows promise that a protocol can be established to provide reproducible data and normative trends in kinetic color visual field testing. The authors recognize that this should be achievable with further refinement of the current testing protocol.

Self-motion illusions from distorted optic flow in multifocal glasses

SummaryProgressive addition lenses (PALs) are ophthalmic lenses to correct presbyopia by providing improvements of near and far vision in different areas of the lens, but distorting the periphery of the wearer's field of view. Distortion-related difficulties reported by PAL wearers include unnatural self-motion perception. Visual self-motion perception is guided by optic flow, the pattern of retinal motion produced by self-motion. We tested the influence of PAL distortions on optic flow-based heading estimation using a model of heading perception and a virtual reality-based psychophysical experiment. The model predicted changes of heading estimation along a vertical axis, depending on visual field size and gaze direction. Consistent with this prediction, participants experienced upwards deviations of self-motion when gaze through the periphery of the lens was simulated, but not for gaze through the center. We conclude that PALs may lead to illusions of self-motion which could be remedied by a careful gaze strategy.

Reorganization of Brain Functional Connectivity Network and Vision Restoration Following Combined tACS-tDCS Treatment After Occipital Stroke.

Objective: Non-invasive brain stimulation (NIBS) is already known to improve visual field functions in patients with optic nerve damage and partially restores the organization of brain functional connectivity networks (FCNs). However, because little is known if NIBS is effective also following brain damage, we now studied the correlation between visual field recovery and FCN reorganization in patients with stroke of the central visual pathway.Method: In a controlled, exploratory trial, 24 patients with hemianopia were randomly assigned to one of three brain stimulation groups: transcranial direct current stimulation (tDCS)/transcranial alternating current stimulation (tACS) (ACDC); sham tDCS/tACS (AC); sham tDCS/sham tACS (Sham), which were compared to age-matched controls (n = 24). Resting-state electroencephalogram (EEG) was collected at baseline, after 10 days stimulation and at 2 months follow-up. EEG recordings were analyzed for FCN measures using graph theory parameters, and FCN small worldness of the network and long pairwise coherence parameter alterations were then correlated with visual field performance.Result: ACDC enhanced alpha-band FCN strength in the superior occipital lobe of the lesioned hemisphere at follow-up. A negative correlation (r = −0.80) was found between the intact visual field size and characteristic path length (CPL) after ACDC with a trend of decreased alpha-band centrality of the intact middle occipital cortex. ACDC also significantly decreased delta band coherence between the lesion and the intact occipital lobe, and coherence was enhanced between occipital and temporal lobe of the intact hemisphere in the low beta band. Responders showed significantly higher strength in the low alpha band at follow-up in the intact lingual and calcarine cortex and in the superior occipital region of the lesioned hemisphere.Conclusion: While ACDC decreases delta band coherence between intact and damaged occipital brain areas indicating inhibition of low-frequency neural oscillations, ACDC increases FCN connectivity between the occipital and temporal lobe in the intact hemisphere. When taken together with the lower global clustering coefficient in responders, these findings suggest that FCN reorganization (here induced by NIBS) is adaptive in stroke. It leads to greater efficiency of neural processing, where the FCN requires fewer connections for visual processing.

How wide should you view to fight? Establishing the size of the visual field necessary for grip fighting in judo

ABSTRACT Peripheral vision is often considered vital in (combat) sports, yet most experimental paradigms (e.g., eye tracking) ignore peripheral information or struggle to make inferences about the role of peripheral vision in an in-situ performance environment. This study aimed to determine where visual information is located in the peripheral field during an in-situ combat sports task. Eight advanced judokas competed in grip-fighting exchanges while wearing a mobile eye-tracker to locate gaze direction. Three-dimensional position data of the head and hands were tracked using a VICON motion capture system. Gaze analysis through automatic feature detection showed that participants predominantly fixated on their opponent’s chest. Kinematic data were used to calculate the angles between the opponent’s hands and the gaze-anchor point on the chest of the opponent. Results revealed a nonlinear relationship between visual field (VF) size and visibility of the hands, with athletes needing a VF of at least 30–40 degrees radius to simultaneously monitor both hands of the opponent most of the time. These findings hold implications for the regulation of Paralympic judo for athletes with vision impairment, suggesting that a less severe degree of impairment should be required to qualify than the current criterion of 20 degrees radius.

Customized eye modeling for optical quality assessment in myopic femto-LASIK surgery

Refractive surgery is recognized as an effective method for myopia treatment, but it can induce night vision disturbances such as glare. We present an eye modeling method for the optical quality assessment in response to the structural changes in the eyes by femto-LASIK surgery. Customized eye models were built from the measurements of 134 right eyes pre- and post-operatively. Optical performance was evaluated using spot diagrams, point spread functions (PSFs), modulation transfer functions (MTFs), and chromatic aberrations at various fields (0°–30°), different pupil diameters (2–6 mm), and initial myopias (− 1.25 to − 10.5 D). Pupil size and initial myopia are the two major factors that affect visual performance of post-operative eyes. The results of spot diagrams, PSFs, and MTFs indicated that post-operative visual performance deteriorated as the visual field and pupil size increased, and it was significantly influenced by initial myopia. Post-operative chromatic aberrations were also affected by initial myopia. As pupil size increased, the post-operative longitudinal chromatic aberrations tended to decrease slightly, while the transverse chromatic aberrations remained similar. The use of eye modeling for refractive surgery assessment could possibly provide a more personalized surgical approach, could improve the prediction accuracy of refractive surgery outcomes, and promote the invention and development of better surgical methods.

Inverse Kinematic Analysis of Bionic Hands Based on Fish Swarm Algorithm

To simplify the solving process of the inverse kinematics problem of a bionic hand, a method of solving the inverse kinematics problem based on an artificial fish swarm algorithm was proposed in this paper. First, the kinematic equations of the bionic hand were established using the Denavit-Hartenberg (D-H) parameters. By selecting the appropriate decision variables and objective functions, an optimization model was established for solving the inverse kinematics problem of the bionic hand. Then, the artificial fish swarm algorithm was used to search the solution space to find the inverse solution of the position of the bionic hand. The results show that the artificial fish swarm algorithm has good convergence performance in solving the kinematic problem of the bionic hand. Besides, the accuracy of the artificial fish swarm algorithm can be improved by adjusting parameters such as the initial number of fish swarms, visual field, crowding degree, and step size.

A touch of hierarchy: population receptive fields reveal fingertip integration in Brodmann areas in human primary somatosensory cortex

Several neuroimaging studies have shown the somatotopy of body part representations in primary somatosensory cortex (S1), but the functional hierarchy of distinct subregions in human S1 has not been adequately addressed. The current study investigates the functional hierarchy of cyto-architectonically distinct regions, Brodmann areas BA3, BA1, and BA2, in human S1. During functional MRI experiments, we presented participants with vibrotactile stimulation of the fingertips at three different vibration frequencies. Using population Receptive Field (pRF) modeling of the fMRI BOLD activity, we identified the hand region in S1 and the somatotopy of the fingertips. For each voxel, the pRF center indicates the finger that most effectively drives the BOLD signal, and the pRF size measures the spatial somatic pooling of fingertips. We find a systematic relationship of pRF sizes from lower-order areas to higher-order areas. Specifically, we found that pRF sizes are smallest in BA3, increase slightly towards BA1, and are largest in BA2, paralleling the increase in visual receptive field size as one ascends the visual hierarchy. Additionally, we find that the time-to-peak of the hemodynamic response in BA3 is roughly 0.5 s earlier compared to BA1 and BA2, further supporting the notion of a functional hierarchy of subregions in S1. These results were obtained during stimulation of different mechanoreceptors, suggesting that different afferent fibers leading up to S1 feed into the same cortical hierarchy.

Case Series on Chiasmal Lesions with Ocular Manifestations seen at the Eye Center of a Tertiary Government Hospital in Philippines

Objective To identify common ocular and non-ocular signs and symptoms of patients with chiasmal lesions presenting to ophthalmologists. Methods This is a three year case series of patients who presented to Rizal Medical Center Ophthalmology OPD clinic, diagnosed as cases of chiasmal lesion with a complete neuro-ophthalmogical exam, ancillary test and neuroimaging. Data collected include patient profile, ocular and non ocular symptoms, duration of blurring of vision (BOV), best corrected visual acuity (BCVA), Color Vision, Optic nerve (ON) description, Visual field defects (VFD) and size & location of chiasmal lesion. Results A total of twelve patients were included with 1:1 M:F ratio and a median age of 39 years. Blurring of Vision was the presenting symptom in 10 cases, bulging of the eyes and headaches in the remaining cases. Associated symptoms include: non specific headache in all; diplopia in 3 (1 with and 2 without motility defects); and systemic symptoms related to hormonal imbalance in 2 cases. Best corrected vision ranged from 6/6 to no light perception (NLP). Color vision was affected in all cases. ON palor was seen in 6 (50%) and disc edema in 1 case. VFD include Junctional scotoma (58.33%), bitemporal hemianopia (33.3%) and generalised scotoma (8.3%). Neuroimaging revealed pituitary lesions in 10 cases, 1 craniopharyngioma and ON glioma with chiasmal extension. Conclusion Ocular and non ocular symptoms seen were comparable to other studies except that Junctional scotoma was the most common VFD identified in the included population of our case series. This highlights the importance of VF testing among patients complaining of unilateral visual loss to rule out a chiasmal lesion.

On the Orbit Orientation and Visual Resolution of Mammalian Gliders

In this study, I analyze the comparative visual system of gliders through orbit and skull dimensions and geometry between gliding rodents, marsupials, and colugos with their non‐gliding relatives. Gliders need: (1) the depth, distance, size, and orientation of target landing substrates prior to takeoff; (2) heading and acceleration data on movement in order to adjust while in air; and (3) to re‐position for landing based on visual approach to the landing substrate. Previous work has suggested that gliding mammals have higher orbit convergence to expand their visual fields or that these animals have larger interorbital distances to increase binocular parallax; both suggestions rely on greater depth perception as underlying functional causes. Additionally, I model the limitations imposed by visual resolution, sensitivity, and visual field sizes on distance and heading perceptions in gliders. Morphometric results do not support the suggestion that orbit dimensions and geometry vary with locomotor type; gliders do not have more convergent or widely spaced orbits. Perhaps more importantly, modeling of visual resolution of substrates at the distances commonly traversed by gliders suggests that these animals cannot rely solely on visual data for locomotor judgments.

Providing care quality by design: a new measure to assess hospital ward layouts

Which hospital ward layout works best? In the past, one response to this question has been to design layouts that minimise walking distances of healthcare workers, and increase the time spent with their patients. However, new research suggests that good face-to-face communication between doctors and nurses crucially impacts the health and safety of patients. Taking this into account, this research proposes a new single measure called Spaces for Communication Index (SCI). It assesses communication opportunities arising from the layout, and shows that a high index is associated with the provision of good healthcare. Six NHS wards were first studied in depth by collecting detailed information about movement and communication patterns of healthcare workers. The index was developed on this basis. Thirty-one NHS wards were then selected, based on their quality of care rating. These were used to test the index. Each ward was analysed with the Space Syntax method, which investigated the size of visual fields of healthcare workers on everyday movement paths through the ward. Large viewsheds provide good visibility and awareness of the environment. As a result, they accrue more communication opportunities by virtue of the layout. Statistical analysis was also used to test if the index can predict care quality. Other factors such as distances between key areas, number of patient beds or ward size were tested, too. Results showed that the higher the index, the better the quality of care. The other factors were not related to healthcare quality. In terms of design, these results highlight the importance of the openness of spaces that healthcare workers traverse to get from one key area to another. This research contributes to the development of an objective method that designers can use to compare different nursing unit designs, and anticipate the care quality that would be provided to patients.

Audiovisual integration capacity modulates as a function of illusory visual contours, visual display circumference, and sound type.

Research into the capacity of audiovisual integration has previously assessed whether capacity is strictly limited to a single item, or whether it can exceed one item under certain environmental conditions. More recently, investigations have turned to examining the effects of various stimulus factors on capacity. Across two experiments, we looked at a number of factors that were expected to play a modulatory role on capacity. Experiment 1 deployed a manipulation of illusory polygons, revealing an increase in audiovisual capacity, even in an absence of visual connections. This demonstrates that exceeding the capacity of 1 does not only represent a functional increase in the binding of a singular, complex visual object, but that it can also represent binding of multiple simpler objects. Findings also support the hypothesis that capacity modulates quantitatively, but not qualitatively, with respect to speed of presentation. Experiment 2 examined the effects of different sound types (sine tones or white noise) and of different spatial visual field sizes on the capacity of audiovisual integration. The results indicate that capacity is maximized when stimuli are presented in a smaller circle (7.5°) if alongside a sine tone, and when presented in a larger circle (18.5°) alongside white noise. These results suggest that audiovisual integration capacity is dependent on the combination of sound type and visual spatial field size. The combination of these results reveal additional phenomenological features of the capacity of audiovisual integration, and provides impetus for further research into applications of the findings.