Improve Depth Perception Research Articles

Machine learning-based augmented reality for improved surgical scene understanding

In orthopedic and trauma surgery, AR technology can support surgeons in the challenging task of understanding the spatial relationships between the anatomy, the implants and their tools. In this context, we propose a novel augmented visualization of the surgical scene that mixes intelligently the different sources of information provided by a mobile C-arm combined with a Kinect RGB-Depth sensor. Therefore, we introduce a learning-based paradigm that aims at (1) identifying the relevant objects or anatomy in both Kinect and X-ray data, and (2) creating an object-specific pixel-wise alpha map that permits relevance-based fusion of the video and the X-ray images within one single view. In 12 simulated surgeries, we show very promising results aiming at providing for surgeons a better surgical scene understanding as well as an improved depth perception.

Improved depth perception with three-dimensional auxiliary display and computer generated three-dimensional panoramic overviews in robot-assisted laparoscopy.

In comparison to open surgery, endoscopic surgery offers impaired depth perception and narrower field-of-view. To improve depth perception, the Da Vinci robot offers three-dimensional (3-D) video on the console for the surgeon but not for assistants, although both must collaborate. We improved the shared perception of the whole surgical team by connecting live 3-D monitors to all three available Da Vinci generations, probed user experience after two years by questionnaire, and compared time measurements of a predefined complex interaction task performed with a 3-D monitor versus two-dimensional. Additionally, we investigated whether the complex mental task of reconstructing a 3-D overview from an endoscopic video can be performed by a computer and shared among users. During the study, 925 robot-assisted laparoscopic procedures were performed in three hospitals, including prostatectomies, cystectomies, and nephrectomies. Thirty-one users participated in our questionnaire. Eighty-four percent preferred 3-D monitors and 100% reported spatial-perception improvement. All participating urologists indicated quicker performance of tasks requiring delicate collaboration (e.g., clip placement) when assistants used 3-D monitors. Eighteen users participated in a timing experiment during a delicate cooperation task in vitro. Teamwork was significantly (40%) faster with the 3-D monitor. Computer-generated 3-D reconstructions from recordings offered very wide interactive panoramas with educational value, although the present embodiment is vulnerable to movement artifacts.

Comparative evaluation of HD 2D/3D laparoscopic monitors and benchmarking to a theoretically ideal 3D pseudodisplay: even well-experienced laparoscopists perform better with 3D

Though theoretically superior to standard 2D visualization, 3D video systems have not yet achieved a breakthrough in laparoscopy. The latest 3D monitors, including autostereoscopic displays and high-definition (HD) resolution, are designed to overcome the existing limitations. We performed a randomized study on 48 individuals with different experience levels in laparoscopy. Three different 3D displays (glasses-based 3D monitor, autostereoscopic display, and a mirror-based theoretically ideal 3D display) were compared to a 2D HD display by assessing multiple performance and mental workload parameters and rating the subjects during a laparoscopic suturing task. Electromagnetic tracking provided information on the instruments' pathlength, movement velocity, and economy. The usability, the perception of visual discomfort, and the quality of image transmission of each monitor were subjectively rated. Almost all performance parameters were superior with the conventional glasses-based 3D display compared to the 2D display and the autostereoscopic display, but were often significantly exceeded by the mirror-based 3D display. Subjects performed a task faster and with greater precision when visualization was achieved with the 3D and the mirror-based display. Instrument pathlength was shortened by improved depth perception. Workload parameters (NASA TLX) did not show significant differences. Test persons complained of impaired vision while using the autostereoscopic monitor. The 3D and 2D displays were rated user-friendly and applicable in daily work. Experienced and inexperienced laparoscopists profited equally from using a 3D display, with an improvement in task performance about 20%. Novel 3D displays improve laparoscopic interventions as a result of faster performance and higher precision without causing a higher mental workload. Therefore, they have the potential to significantly impact the further development of minimally invasive surgery. However, as shown by the custom-built 3D mirror display, this effect can be improved, thus stimulating further research.

An Evaluation of Depth Enhancing Perceptual Cues for Vascular Volume Visualization in Neurosurgery

Cerebral vascular images obtained through angiography are used by neurosurgeons for diagnosis, surgical planning, and intraoperative guidance. The intricate branching of the vessels and furcations, however, make the task of understanding the spatial three-dimensional layout of these images challenging. In this paper, we present empirical studies on the effect of different perceptual cues (fog, pseudo-chromadepth, kinetic depth, and depicting edges) both individually and in combination on the depth perception of cerebral vascular volumes and compare these to the cue of stereopsis. Two experiments with novices and one experiment with experts were performed. The results with novices showed that the pseudo-chromadepth and fog cues were stronger cues than that of stereopsis. Furthermore, the addition of the stereopsis cue to the other cues did not improve relative depth perception in cerebral vascular volumes. In contrast to novices, the experts also performed well with the edge cue. In terms of both novice and expert subjects, pseudo-chromadepth and fog allow for the best relative depth perception. By using such cues to improve depth perception of cerebral vasculature, we may improve diagnosis, surgical planning, and intraoperative guidance.

Comparative Effectiveness of 3-Dimensional vs 2-Dimensional and High-Definition vs Standard-Definition Neuroendoscopy

BACKGROUND:Although the potential benefits of 3-dimensional (3-D) vs 2-dimensional (2-D) and high-definition (HD) vs standard-definition (SD) endoscopic visualization have long been recognized in other surgical fields, such endoscopes are generally considered too large and bulky for use within the brain. The recent development of 3-D and HD neuroendoscopes may therefore herald improved depth perception, better appreciation of anatomic details, and improved overall surgical performance.OBJECTIVE:To compare simultaneously the effectiveness of 3-D vs 2-D and HD vs SD neuroendoscopy.METHODS:Ten novice neuroendoscopic surgeons were recruited from a university hospital. A preclinical randomized crossover study design was adopted to compare 3-D vs 2-D and HD vs SD neuroendoscopy. The primary outcomes were time to task completion and accuracy. The secondary outcomes were perceived task workload using the NASA (National Aeronautics and Space Administration) Task Load Index and subjective impressions of the endoscopes using a 5-point Likert scale.RESULTS:Time to task completion was significantly shorter when using the 3-D vs the 2-D neuroendoscopy (P = .001), and accuracy of probe placement was significantly greater when using the HD vs the SD neuroendoscopy (P = .009). We found that 3-D endoscopy significantly improved perceived depth perception (P < .001), HD endoscopy significantly improved perceived image quality (P < .001), and both improved participants’ overall impression (P < .001).CONCLUSION:Three-dimensional neuroendoscopy and HD neuroendoscopy have differing but complementary effects on surgical performance, suggesting that neither alone can completely compensate for the lack of the other. There is therefore strong preclinical evidence to justify 3-D HD neuroendoscopy.ABBREVIATIONS:HD, high definitionSD, standard definition

A Novel Virtual Reality Simulation for Hemostasis in a Brain Surgical Cavity: Perceived Utility for Visuomotor Skills in Current and Aspiring Neurosurgery Residents

To understand the perceived utility of a novel simulator to improve operative skill, eye-hand coordination, and depth perception. We used the ImmersiveTouch simulation platform (ImmersiveTouch, Inc., Chicago, Illinois, USA) in two U.S. Accreditation Council for Graduate Medical Education-accredited neurosurgical training programs: the University of Chicago and the University of Texas Medical Branch. A total of 54 trainees participated in the study, which consisted of 14 residents (group A), 20 senior medical students who were neurosurgery candidates (group B), and 20 junior medical students (group C). The participants performed a simulation task that established bipolar hemostasis in a virtual brain cavity and provided qualitative feedback regarding perceived benefits in eye-hand coordination, depth perception, and potential to assist in improving operating skills. The perceived ability of the simulator to positively influence skills judged by the three groups: group A, residents; group B, senior medical students; and group C, junior medical students was, respectively, 86%, 100%, and 100% for eye-hand coordination; 86%, 100%, and 95% for depth perception; and 79%, 100%, and 100% for surgical skills in the operating room. From all groups, 96.2% found the simulation somewhat or very useful to improve eye-hand coordination, and 94% considered it beneficial to improve depth perception and operating room skills. This simulation module may be suitable for resident training, as well as for the development of career interest and skill acquisition; however, validation for this type of simulation needs to be further developed.

Enabling stereoscopic high dynamic range video

Stereoscopic and high dynamic range (HDR) imaging are two methods that enhance video content by respectively improving depth perception and light representation. A large body of research has looked into each of these technologies independently, but very little work has attempted to combine them due to limitations in capture and display; HDR video capture (for a wide range of exposure values over 20 f-stops) is not yet commercially available and few prototype HDR video cameras exist. In this work we propose techniques which facilitate stereoscopic high dynamic range (SHDR) video capture by using an HDR and LDR camera pair. Three methods are proposed: one based on generating the missing HDR frame by warping the existing one using a disparity map; increasing the range of LDR video using a novel expansion operator; and a hybrid of the two where expansion is used for pixels within the LDR range and warping for the rest. Generated videos were compared to the ground truth SHDR video captured using two HDR video cameras. Results show little overall error and demonstrate that the hybrid method produces the least error of the presented methods.

Three-Dimensional High-Definition Neuroendoscopic Surgery: A Controlled Comparative Laboratory Study with Two-Dimensional Endoscopy and Clinical Application

The purpose of this research was to investigate the usefulness of three-dimensional (3D) endoscopy compared with two-dimensional (2D) endoscopy in neuroendoscopic surgeries in a comparative study and to test the clinical applications. Forty-three examinees were divided into three groups according to their endoscopic experience: novice, beginner, or expert. Examinees performed three separate tasks using 3D and 2D endoscopy. A recently developed 3D high-definition (HD) neuroendoscope, 4.7 mm in diameter (Shinko Optical Co., Ltd., Tokyo, Japan) was used. In one of the three tasks, we developed a full-sized skull model of acrylic-based plastic using a 3D printer and a patient's thin slice computed tomography data, and evaluated the execution time and total path length of the tip of the pointer using an optical tracking system. Sixteen patients underwent endoscopic transnasal transsphenoidal pituitary surgery using both 3D and 2D endoscopy. Horizontal motion was evaluated using task 1, and anteroposterior motion was evaluated with task 3. Execution time and total path length in task 3 using the 3D system in both novice and beginner groups were significantly shorter than with the 2D system (p < 0.05), although no significant difference between 2D and 3D systems in task 1 was seen. In both the novice and beginner groups, the 3D system was better for depth perception than horizontal motion. No difference was seen in the expert group in this regard. The 3D HD endoscope was used for the pituitary surgery and was found very useful to identify the spatial relationship of carotid arteries and bony structures. The use of a 3D neuroendoscope improved depth perception and task performance. Our results suggest that 3D endoscopes could shorten the learning curve of young neurosurgeons and play an important role in both general surgery and neurosurgery.

Three-Dimensional Direct Laryngoscopy and Bronchoscopy

This is the first description of 3-dimensional (3D) pediatric airway endoscopy in the otolaryngology literature detailing the superior visualization with this technology. Ultimately, enhanced optics may further improve the treatment of airway pathology. To report the first case series examining the use of 3D direct laryngoscopy and bronchoscopy (DLB) in the diagnosis and management of laryngotracheal pathology. Case series. Tertiary care pediatric hospital. Three patients underwent both telescopic 2-dimensional (2D) and 3D DLB for comparison purposes: a 12-year-old boy for visualization of complete tracheal rings, a 23-year-old man for dilation of tracheal stenosis, and a 4-month-old boy for resection of subglottic cysts. Enhanced visualization of laryngotracheal pathology and facilitated endoscopic surgery. To our knowledge, this is the first case series in the otolaryngology literature examining the use of 3D DLB for the resection of subglottic cysts, dilation of tracheal stenosis, and visualization of complete tracheal rings. We believe that the 3D view offers qualitatively improved depth perception, accuracy of balloon placement, and appraisal of subglottic cyst resection margins. This emerging technology has vast potential for improving endoscopy, surgical precision in airway interventions, tissue preservation, and methods of teaching. More research is needed in this area regarding the benefits and advantages of 3D compared with 2D endoscopy.

Introducing artificial depth cues to improve task performance in ITER maintenance actions

Maintenance operations on ITER tokamak components will be largely performed by remote handling. In previous work it was shown that representative maintenance tasks could be performed significantly faster with direct visual feedback than with camera feedback. In post-test interviews, operators indicated that they regarded the lack of 3D perception as the primary factor hindering their performance.This paper discusses various techniques to improve depth perception in teleoperation, including stereo vision, head tracking, virtual camera views and depth gauges. The most promising techniques were tested. Performance metrics included time-to-complete, path analysis and operator work-load.In a first experiment, artificial depth gauges views were tested in a 1:1 scale hardware testbed with mechanical master-slave manipulators handled by experienced operators. Robust real-time image processing was achieved with marker-based objects. The simple depth gauge and graphical overlay did not significantly improve task performance. Operators commented on their view of the task being “obstructed” by the graphical overlay, and the depth gauge was judged not very informative.In a second experiment, real time tracking was combined with VR display including stereo and head tracking. While stereo was found to improve the task performance significantly over the 1 camera (mono) condition, head tracking unexpectedly did not.

Effectively Visualizing the Spatial Structure of Cerebral Blood Vessels

Three-dimensional visualizations of cerebral vessel structures are helpful for diagnosing diseases. However, when viewing several overlapping cerebral vessels using traditional ray casting, it's difficult to decide clear depth ordering. As a solution, distance color blending and stereoscopic depth enhancement are combined with CUDA-based pre-integrated volume rendering and its advanced transfer function for improved depth perception.

847 3D-LAPAROSCOPIC IMAGING IMPROVES SURGICAL PERFORMANCE ON STANDARDIZED LAPAROSCOPIC TASKS

You have accessJournal of UrologyTechnology & Instruments: Laparoscopy - Malignant Disease1 Apr 2012847 3D-LAPAROSCOPIC IMAGING IMPROVES SURGICAL PERFORMANCE ON STANDARDIZED LAPAROSCOPIC TASKS Patrick Honeck, Gunnar Wendt-Nordahl, Jens Rassweiler, and Thomas Knoll Patrick HoneckPatrick Honeck Sindelfingen, Germany More articles by this author , Gunnar Wendt-NordahlGunnar Wendt-Nordahl Sindelfingen, Germany More articles by this author , Jens RassweilerJens Rassweiler Heilbronn, Germany More articles by this author , and Thomas KnollThomas Knoll Sindelfingen, Germany More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.939AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Laparoscopy has been limited by the lack of depth perception and spatial orientation by using two-dimensional imaging. This directly affects surgical performance, operative time, and morbidity. Three-dimensional vision offers the advantage of improved depth perception and accuracy. This study was designed to evaluate the effect of 3-dimensional imaging on the performance of novice and experienced laparoscopic surgeons executing standardized laparoscopic tasks in an ex-vivo setting. METHODS A 3-dimensional imaging system with a digital 3D full HD (Einstein system, Schölly Fiberoptics, Germany) and a 2-dimensional imaging with a conventional HDTV camera were used. A total of 10 laparoscopic experts and 10 novices were evaluated while performing standardized skill tasks in a pelvic trainer. Participants were devided into 2 groups working either with 2-dimensional or 3-dimensional imaging. The parameters measured were time until completion of each skill and total procedure time, number of losses of working material, number of missed grasps and number of needed support. Statistical analysis was performed using the Wilcoxon test. RESULTS The results showed s significant difference in favor of the 3-dimensional system for the amount of missed grasps in the experts as well as the novice group (p<0.0001). A slightly significant difference was also seen for the loss of working materials (p=0.0381 and p=0.0693). The study is limited by its small sample size. CONCLUSIONS The Einstein 3-dimensional imaging system sigificantly improves spatial orentation and depth perception during laparoscopy under ex-vivo conditions. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e345 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Patrick Honeck Sindelfingen, Germany More articles by this author Gunnar Wendt-Nordahl Sindelfingen, Germany More articles by this author Jens Rassweiler Heilbronn, Germany More articles by this author Thomas Knoll Sindelfingen, Germany More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Transnasal Skull Base Reconstruction Using a 3-D Endoscope: Our First Impressions

Nowadays endoscopic skull base reconstruction is safely and effectively performed by means of two-dimensional (2-D) endoscopic technique. The aim of our study is to compare our 2-D experience with the novel 3-D technology in the field of skull base reconstruction techniques. In this study four patients treated with various kinds of planned duraplasty are included. The new 3-D technology was compared with the high-definition 2-D scopes during the different steps of the procedures. The 3-D endoscopic skull base reconstruction obtained primary closure without complications in all cases. According to the subjective opinion of experienced endosurgeons, this novel technique improved depth perception, distance and size estimation, ability to identify specific anatomic structures, and hand-eye coordination. The main drawbacks detected were inferior sharpness, contrast and lighting that impaired the application of the technique in narrow sinonasal spaces. According to our preliminary impressions, 3-D endoscopic skull base reconstruction is an effective and safe procedure and could represent a significant advantage for accurate managing of the skull base region.

The Right View from the Wrong Location: Depth Perception in Stereoscopic Multi-User Virtual Environments

Stereoscopic depth cues improve depth perception and increase immersion within virtual environments (VEs). However, improper display of these cues can distort perceived distances and directions. Consider a multi-user VE, where all users view identical stereoscopic images regardless of physical location. In this scenario, cues are typically customized for one "leader" equipped with a head-tracking device. This user stands at the center of projection (CoP) and all other users ("followers") view the scene from other locations and receive improper depth cues. This paper examines perceived depth distortion when viewing stereoscopic VEs from follower perspectives and the impact of these distortions on collaborative spatial judgments. Pairs of participants made collaborative depth judgments of virtual shapes viewed from the CoP or after displacement forward or backward. Forward and backward displacement caused perceived depth compression and expansion, respectively, with greater compression than expansion. Furthermore, distortion was less than predicted by a ray-intersection model of stereo geometry. Collaboration times were significantly longer when participants stood at different locations compared to the same location, and increased with greater perceived depth discrepancy between the two viewing locations. These findings advance our understanding of spatial distortions in multi-user VEs, and suggest a strategy for reducing distortion.

A Controlled Laboratory and Clinical Evaluation of a Three-dimensional Endoscope for Endonasal Sinus and Skull Base Surgery

One criticism of current video systems for endoscopic surgery is that two-dimensional (2D) images lack depth perception and may impair surgical dissection. To objectively measure the efficacy of 3D endoscopy, we designed a training model with specific tasks to show potential differences between 2D and 3D endoscopy. Its clinical value was then evaluated during endoscopic sinus and skull base surgical cases. Fifteen subjects were grouped according to endoscopic experience: novices and nonnovices. A training model was constructed to include five tasks: incision manipulation; ring transfer; nerve hook; distance estimation, visual only; and distance estimation, visual and tactile. Each participant was assessed with both a standard 2D endoscope and a 3D endoscope. The clinical value of a 3D endoscope (Visionsense, Ltd., Petach Tikva, Israel) was then examined in four endoscopic sinus cases and four skull base cases. Of the subjects, six (40%) were novices. Overall, the errors committed during any one task were not significantly different between systems. Novices trended toward more success during the nerve hook task using the 3D system. With size cueing versus visualization alone, distance estimation was significantly more accurate. Novices tended to prefer the 3D system and experienced surgeons disliked the initial learning curve. Advantages were particularly noticed during skull base surgery; subjectively improved depth perception was beneficial during vascular dissection. Three-dimensional endoscopy may improve depth perception and performance for novices. The 3D endoscope is a safe and feasible tool for endoscopic sinus and skull base surgery; it is promising for improving microneurosurgical dissection precision transnasally.

Combination of Binocular Disparity and Motion Parallax Does Not Contribute to the Fixing of Depth Reversal

The visual phenomenon that perceived depth sign is opposite to depth sign geometrically predicted from binocular disparity or motion parallax is known as depth reversal (Gillam, 1967; Hayashibe, 1991). Combination of binocular disparity and motion parallax generally improve depth perception (Nawrot & Blake, 1991). In the current study, we investigated if the combined display contributes to the fixing of depth reversal. In a dark room, a surface slanted about a vertical axis was displayed for 800 ms by binocular cue only, by motion cue only, or by binocular and motion cues. Six subjects judged the apparent slant. Overall, mean frequencies of reports of reverse slant were 78.2%, 36.8%, and 78.6% for binocular cue only, motion cue only, and binocular and motion cues, respectively. Namely, combination of binocular disparity and motion parallax does not contribute to the fixing of depth reversal.

Advanced volume illumination with unconstrained light source positioning.

Advanced volume visualization techniques are important for both visual arts and visualization. An interactive volumetric lighting model simulates scattering and shadowing to generate high-quality images. Compared to gradient-based shading, this model achieves superior image quality and higher frame rates. User study results indicate that this model can also significantly improve depth perception.

Hand-assisted laparoscopic surgery is associated with enhanced depth perception in novices

The visual information obtained in hand-assisted laparoscopic surgery (HALS) and total laparoscopy is based on two-dimensional depth cues. This study was designed to test the hypothesis that intracorporeal hand improves depth perception in HALS. Ten subjects were divided into two groups using HALS or total laparoscopy. The first task was passing a 10-cm thread through four small metallic loops five times; the second was tying 30 square three-throw intracorporeal laparoscopic knots. End points were (1) number of past pointing as an index of movement accuracy and reflection of depth perception, (2) execution time, and (3) knot quality score. The HALS group was significantly faster than total laparoscopy with a median (interquartile range (IQR)) of 117 s (75.5) vs. 179 s (235.5; P = 0.001) for the thread passing task and 97 s (43.3) vs. 130 s (68.3; P < 0.0005) for knot tying. The number of past-pointing events was significantly lower with HALS compared with total laparoscopy with a median (IQR) of 12 (8) vs. 23 (24; P = 0.001) for the thread passing task and 7 (5) vs. 13 (10; P < 0.0005) for knot tying. There was a significant main effect of whether the targeted object was in contact with the other instrument in knot tying task when past-pointing occurred (P = 0.031). No difference in a knot quality score was found between the HALS and total laparoscopy. The accuracy of instrument movement was significantly better in the HALS group compared with total laparoscopy. The study confirmed the hypothesis that intracorporeal hand improves depth perception in HALS. Also, the touch of the assisting instrument with the target object enhances spatial orientation in the laparoscopic operative field. However, further study is needed to test the hypothesis in experts.

Evolution of primate special senses

The origin and early cladogenesis of primates involved several critical shifts in sensory anatomy and ecology. Comparisons of living and fossil euarchontans suggest that the origin of crown primates was associated with the evolution of (a) increased eye size and (b) greater optic convergence. Functional and comparative evidence indicates that these features are best explained as adaptations for increased visual acuity and improved depth perception in the context of nocturnal visual predation. A second major shift in primate sensory anatomy occurred with the origin of crown Haplorhini. Most living haplorhines share a suite of highly derived adaptations for enhanced visual acuity, including (a) small corneas relative to eye size, (b) a retinal fovea, and (c) a postorbital septum. Haplorhines also demonstrate a derived reduction of the olfactory apparatus, including (a) loss of the rhinarium, (b) loss of an olfactory recess in the nasal cavity, and (c) decreased olfactory bulb size. While the underlying causes of olfactory reduction remain obscure, enhanced visual acuity likely evolved in haplorhines as an adaptation for visually directed predation in a diurnal setting.

Real 3D increases perceived depth over anaglyphs but does not cancel stereo-anomaly

Background About 30% of the population has difficulties detecting the sign and the magnitude of binocular disparity in the absence of eye movements, a phenomenon called stereo-anomaly. The stereo-anomaly tests so far are based on disparity only (e.g. red–green stereograms), which means that other depth cues cannot be used and even provide conflicting depth information. Objective Here we investigate whether stereo-anomaly also occurs using a “true-3D” display which provides other depth cues that are all consistent with one particular distance in depth. Secondly, we examine differences in depth perception between red–green (anaglyphic) and true-3D displays. Finally, we test the displays’ relative viewing comfort. Method Sixteen observers (four of which were stereo-anomalous) judged the distance in depth between a fixation square and one or two bars. They were presented on an anaglyphic and a true-3D display, both in the fovea and 5 deg in the visual periphery. Observers were asked about the viewing comfort of both displays. Results Stereo-anomalous observers also showed difficulties in perceiving depth with the true-3D display. Yet the true-3D display increased the perceived depth range compared to the red–green display for practically all observers at both eccentricities. All observers reported greater viewing comfort for the true-3D display. Conclusion Stereo-anomaly is a robust phenomenon. True-3D displays improve depth perception and viewing comfort, most likely because retinal blur provides depth information consistent with disparity. Application The true-3D display shows potential for clearly and comfortably displaying objects at different depth planes.