Pilot study of a pedestrian collision detection test for a multisite trial of field expansion devices for hemianopia.

Significance: Performance-based outcome measures are crucial for clinical trials of field expansion devices. We implemented a test simulating a real-world mobility situation, focusing on detection of a colliding pedestrian among multiple noncolliding pedestrians, suitable for measuring the effects of homonymous hemianopia and assistive devices in clinical trials.

Purpose: In preparation for deploying the test in a multisite clinical trial, we conducted a pilot study to gather preliminary data on blind-side collision detection performance with multiperiscopic peripheral prisms compared with Fresnel peripheral prisms.

Understanding viewpoint changes in peripheral prisms for field expansion by virtual reality simulation.

Prism field expansion is a common treatment for patients with peripheral field loss, shifting images from the blind field into the seeing field. The shifted image originates from a new viewpoint translated and rotated from the original viewpoint by the prism. To understand such viewpoint changes, we simulated two field expansion methods in virtual reality: 1) angular (i.

Egocentric Boundaries on Distinguishing Colliding and Non-Colliding Pedestrians while Walking in a Virtual Environment.

Avoiding person-to-person collisions is critical for visual field loss patients. Any intervention claiming to improve the safety of such patients should empirically demonstrate its efficacy. To design a VR mobility testing platform presenting multiple pedestrians, a distinction between colliding and non-colliding pedestrians must be clearly defined.

A rare case of ductal variant multilocular prostatic cystadenocarcinoma invading the rectum.

Prostate papillary and cribriform ductal prostatic adenocarcinoma is a rare malignancy infrequently reported in the literature. We describe a case of rectally invasive prostate cystic adenocarcinoma and surgical extirpative management not requiring fecal or urinary diversion.

Development of Virtual Reality Walking Collision Detection Test on Head-mounted display.

Detecting and avoiding collisions during walking is critical for safe mobility. To determine the effectiveness of clinical interventions, a realistic objective outcome measure is needed. A real-world obstacle course with moving hazards has numerous limitations (e.

Metastatic papillary thyroid carcinoma presenting as an isolated renal mass: Case report and review of the literature.

Distant metastasis of Papillary Thyroid Cancer (PTC) to the kidney(s), while rare, has been observed, with approximately 30 cases described in the literature. We present the case of a 28-year-old male who was diagnosed with metastatic PTC following resection of a solitary renal mass. Pathological analysis of the thyroid gland following subsequent thyroidectomy revealed positive regional lymph nodes consistent with metastatic PTC, however, no evidence of malignancy was identified in the thyroid gland.

Self-position awareness based presence and interaction in virtual reality.

The awareness of self-position, which refers to the location of our cyclopean eye, is essential to the experience of being immersed and for interacting with a virtual environment. Currently, individual variability in the cyclopean eye location is not considered when presenting virtual reality (VR) content. The effect of the cyclopean eye shift was analyzed with theoretical and experimental methods, and it was found that human vision is sensitive to the visual direction offset caused by the cyclopean eye shift.

A Pilot Study on EEG-Based Evaluation of Visually Induced Motion Sickness.

The most prominent problem in virtual reality (VR) technology is that users may experience motion sickness-like symptoms when they immerse into a VR environment. These symptoms are recognized as visually induced motion sickness (VIMS) or virtual reality motion sickness (VRMS). The objectives of this study were to investigate the association between the electroencephalogram (EEG) and subjectively rated VIMS level (VIMSL) and find the EEG markers for VIMS evaluation.

Stereoscopic 3D Optic Flow Distortions Caused by Mismatches between Image Acquisition and Display Parameters.

We analyze the impact of common stereoscopic 3D (S3D) depth distortion on S3D optic flow in virtual reality (VR) environments. The depth distortion is introduced by mismatches between the image acquisition and display parameter. The results show that such S3D distortions induce large S3D optic flow distortions and may even induce partial/full optic flow reversal within a certain depth range, depending on the viewer's moving speed and the magnitude of S3D distortion introduced.

IMPACT OF HEADLIGHT GLARE ON PEDESTRIAN DETECTION WITH UNILATERAL CATARACT.

Detecting pedestrians while driving at night is difficult, and is further impeded by oncoming headlight glare (HLG). Cataracts increase intraocular light scattering, making the task even more challenging. We used a within-subjects repeated measures design to determine the impact of HLG on driving with unilateral cataract.

Comparison of Pedestrian Detection With and Without Yellow-Lens Glasses During Simulated Night Driving With and Without Headlight Glare.

Importance: Some marketing materials for yellow-lens night-driving glasses claim that they increase nighttime road visibility and reduce oncoming headlight glare (HLG). However, there is no scientific evidence to support these claims.

Objective: To measure the association between yellow-lens glasses and the detection of pedestrians with and without an oncoming HLG, using a driving simulator equipped with a custom HLG simulator.

Correcting geometric distortions in stereoscopic 3D imaging.

Motion in a distorted virtual 3D space may cause visually induced motion sickness. Geometric distortions in stereoscopic 3D can result from mismatches among image capture, display, and viewing parameters. Three pairs of potential mismatches are considered, including 1) camera separation vs.

Impact of Oncoming Headlight Glare With Cataracts: A Pilot Study.

Oncoming headlight glare (HLG) reduces the visibility of objects on the road and may affect the safety of nighttime driving. With cataracts, the impact of oncoming HLG is expected to be more severe. We used our custom HLG simulator in a driving simulator to measure the impact of HLG on pedestrian detection by normal vision subjects with simulated mild cataracts and by patients with real cataracts.

Rapid Adaptation of Night Vision.

Apart from the well-known loss of color vision and of foveal acuity that characterizes human rod-mediated vision, it has also been thought that night vision is very slow (taking up to 40 min) to adapt to changes in light levels. Even cone-mediated, daylight, vision has been thought to take 2 min to recover from light adaptation. Here, we show that most, though not all adaptation is rapid, taking less than 0.

New Contrast Metric for Realistic Display Performance Measure.

The contrast ratio (CR) has been used to describe display's performance. However, CR is unbound, ignores the impact of ambient illumination, or viewer's contrast perception. We propose new metric for display's contrast performance based on a modified Weber contrast definition that considers human contrast adaptation and applies for both opaque and see-through displays.

Positive and negative polarity contrast sensitivity measuring app.

Contrast sensitivity (CS) quantifies an observer's ability to detect the smallest (threshold) luminance difference between a target and its surrounding. In clinical settings, printed letter contrast charts are commonly used, and the contrast of the letter stimuli is specified by the Weber contrast definition. Those paper-printed charts use negative polarity contrast (NP, dark letters on bright background) and are not available with positive polarity contrast (PP, bright letters on dark background), as needed in a number of applications.

An augmented-reality edge enhancement application for Google Glass.

Purpose: Google Glass provides a platform that can be easily extended to include a vision enhancement tool. We have implemented an augmented vision system on Glass, which overlays enhanced edge information over the wearer's real-world view, to provide contrast-improved central vision to the Glass wearers. The enhanced central vision can be naturally integrated with scanning.

Development of a Headlight Glare Simulator for a Driving Simulator.

We describe the design and construction of a headlight glare simulator to be used with a driving simulator. The system combines a modified programmable off-the-shelf LED display board and a beamsplitter so that the LED lights, representing the headlights of oncoming cars, are superimposed over the driving simulator headlights image. Ideal spatial arrangement of optical components to avoid misalignments of the superimposed images is hard to achieve in practice and variations inevitably introduce some parallax.

Instability of the perceived world while watching 3D stereoscopic imagery: A likely source of motion sickness symptoms.

Watching 3D content using a stereoscopic display may cause various discomforting symptoms, including eye strain, blurred vision, double vision, and motion sickness. Numerous studies have reported motion-sickness-like symptoms during stereoscopic viewing, but no causal linkage between specific aspects of the presentation and the induced discomfort has been explicitly proposed. Here, we describe several causes, in which stereoscopic capture, display, and viewing differ from natural viewing resulting in static and, importantly, dynamic distortions that conflict with the expected stability and rigidity of the real world.

Semantic guidance of eye movements in real-world scenes.

The perception of objects in our visual world is influenced by not only their low-level visual features such as shape and color, but also their high-level features such as meaning and semantic relations among them. While it has been shown that low-level features in real-world scenes guide eye movements during scene inspection and search, the influence of semantic similarity among scene objects on eye movements in such situations has not been investigated. Here we study guidance of eye movements by semantic similarity among objects during real-world scene inspection and search.

A model of top-down attentional control during visual search in complex scenes.

Recently, there has been great interest among vision researchers in developing computational models that predict the distribution of saccadic endpoints in naturalistic scenes. In many of these studies, subjects are instructed to view scenes without any particular task in mind so that stimulus-driven (bottom-up) processes guide visual attention. However, whenever there is a search task, goal-driven (top-down) processes tend to dominate guidance, as indicated by attention being systematically biased toward image features that resemble those of the search target.