Drilling into the functional significance of stereopsis: the impact of stereoscopic information on surgical performance

The value of stereoscopic three-dimensional vision on dental students' performance in a virtual reality simulator

PURPOSE/OBJECTIVES

The aim of this study was to quantitatively investigate the impact of stereoscopic three-dimensional (3D) vision on students' performance when compared with that of two-dimensional (2D) vision in a 3D virtual reality (VR) simulator.

METHODS

Twenty-four dental students (second- and fourth-year BDS) were assigned to perform three operative tasks under 3D and 2D viewing conditions on a Virteasy (HRV) simulator. Groups were crossed over and all students performed the same tasks under the alternate viewing conditions. The performance was evaluated by (1) accuracy, (2) outside target area removal, and (3) tooth cutting time, automatically using the generated feedback.

RESULTS

Twenty-one participants completed all sessions. The results revealed a statistically significant effect of 3D vision over 2D vision on students' performance in terms of accuracy (p = 0.035). Stereoscopic 3D vision showed significant effect on outside target area removal in the first task (p = 0.035). Tooth cutting time was the same under both conditions (p = 0.766). The findings revealed improvement in accuracy score and reduction in outside target area removal over the course of the experiment under both conditions. Comparing the difference in 3D effect in the early and advanced learning groups revealed no significant difference among the groups (p > 0.05).

CONCLUSION

Utilizing stereoscopic 3D vision in the training session improved students' perception of depth which led to more accurate tooth cutting within the target area, and less outside target area removal. However, 3D shows a limited impact on task completion time.

Association between stereoacuity and simulated clinical performance among dental students: an exploratory investigation

INTRODUCTION

Dentistry is a profession that requires a high level of the hand-eye coordination. Although considerable attention has been put on dental students' manual dexterity, little emphasis was made on students' visual competency as a variable influencing their competency. In this study, we aimed to assess the association between dental students' stereopsis and their pre-clinical performance.

METHODS

Dental students (n = 49) were required to perform the porcelain-fused-to-crown preparation for a lower first molar and an upper central incisor plastic teeth mounted on phantom heads. Performance was assessed by two faculty members based on two rubrics, which collectively included 11 assessment criteria. Afterward, students undertook a stereoacuity test using Randot stereotest. Stereopsis values greater than 40 arc/s were considered abnormal.

RESULTS

A significant negative correlation was seen between stereopsis scores and students' grades for the upper incisor (p < 0.01), but not for the lower molar. An association was also seen between abnormal stereopsis and students' poor performance in preparing the finish line of the incisor tooth (p = 0.024).

CONCLUSION

Abnormal stereopsis can impact dental students' performance, particularly when preparing teeth indirectly using a dental mirror. Dental educators should give attention to students' stereoacuity, in a manner similar to that given to students' manual dexterity.

Simulated skill complexity and perceived cognitive load during preclinical dental training

INTRODUCTION

Cognitive Load theory (CLT) focuses on the information processing aspect of learning and how the working memory handles the mental effort associated with new task. The aim of this study is to investigate the association between the perceived cognitive load and performance amongst dental students during preclinical simulation training at various levels of procedural task complexity. Additionally, some cognitive load-modifying factors were examined.

MATERIALS AND METHODS

This cross-sectional study evaluated the perceived cognitive load amongst second-year dental students (n = 34), using the validated National Aeronautics and Space Administration's Task Load Index (NASA TLX index) after training on four dental tasks at two levels of complexity, in addition to structured online anonymous questionnaire about demographics, feedback and performance. The NASA TLX raw scores and the weighted global score were calculated for each exercise. Descriptive statistics and Pearson's correlations between performance and the corresponding NASA TLX-weighted score were calculated. Mean differences in the perceived cognitive load across the exercise levels were assessed using RM-ANOVA with Bonferroni corrections at p < .05.

RESULTS

Reduced performance was significantly associated with higher cognitive load particularly in high complexity dental task (class II-mirror vision). Simulated exercise complexity significantly influenced the students' perceived mental demand, physical demand and temporal demand; all were significantly higher for class II- mirror vision task than for direct vision tasks. The majority of participants (82.1%) preferred detailed feedback from instructors, and more than half of the participants (60.7%) preferred continuous feedback throughout the training session.

CONCLUSION

Complex dental tasks are associated with higher cognitive load in novice dental students during preclinical training. The NASA TLX index is a useful instrument to explore the level of perceived cognitive load associated with performance of simulated complex dental skills. Cognitive load theory is relevant to simulation-based dental education to improve the preclinical instructional efficiency and to enhance students learning.

The effect of 3D stereopsis and hand-tool alignment on learning effectiveness and skill transfer of a VR-based simulator for dental training

Recent years have seen the proliferation of VR-based dental simulators using a wide variety of different VR configurations with varying degrees of realism. Important aspects distinguishing VR hardware configurations are 3D stereoscopic rendering and visual alignment of the user's hands with the virtual tools. New dental simulators are often evaluated without analysing the impact of these simulation aspects. In this paper, we seek to determine the impact of 3D stereoscopic rendering and of hand-tool alignment on the teaching effectiveness and skill assessment accuracy of a VR dental simulator. We developed a bimanual simulator using an HMD and two haptic devices that provides an immersive environment with both 3D stereoscopic rendering and hand-tool alignment. We then independently controlled for each of the two aspects of the simulation. We trained four groups of students in root canal access opening using the simulator and measured the virtual and real learning gains. We quantified the real learning gains by pre- and post-testing using realistic plastic teeth and the virtual learning gains by scoring the training outcomes inside the simulator. We developed a scoring metric to automatically score the training outcomes that strongly correlates with experts' scoring of those outcomes. We found that hand-tool alignment has a positive impact on virtual and real learning gains, and improves the accuracy of skill assessment. We found that stereoscopic 3D had a negative impact on virtual and real learning gains, however it improves the accuracy of skill assessment. This finding is counter-intuitive, and we found eye-tooth distance to be a confounding variable of stereoscopic 3D, as it was significantly lower for the monoscopic 3D condition and negatively correlates with real learning gain. The results of our study provide valuable information for the future design of dental simulators, as well as simulators for other high-precision psycho-motor tasks.

Exploring the Presence of Core Skills for Surgical Practice Through Simulation

OBJECTIVE

The ability to simulate procedures in silico has transformed surgical training and practice. Today's simulators, designed for the training of a highly specialized set of procedures, also present a powerful scientific tool for understanding the neural control processes that underpin the learning and application of surgical skills. Here, we examined whether 2 simulators designed for training in 2 different surgical domains could be used to examine the extent to which fundamental sensorimotor skills transcend surgical specialty.

DESIGN, SETTING & PARTICIPANTS

We used a high-fidelity virtual reality dental simulator and a laparoscopic box simulator to record the performance of 3 different groups. The groups comprised dentists, laparoscopic surgeons, and psychologists (each group n = 19).

RESULTS

The results revealed a specialization of performance, with laparoscopic surgeons showing the highest performance on the laparoscopic box simulator, while dentists demonstrated the highest skill levels on the virtual reality dental simulator. Importantly, we also found that a transfer learning effect, with laparoscopic surgeons and dentists showing superior performance to the psychologists on both tasks.

CONCLUSIONS

There are core sensorimotor skills that cut across surgical specialty. We propose that the identification of such fundamental skills could lead to improved training provision prior to specialization.

The utility of haptic simulation in early restorative dental training: A scoping review

BACKGROUND

Haptic dental simulators are becoming increasingly available in dental schools around the world; however, there is a paucity of evidence on their pedagogical effectiveness particularly in early dental training for the acquisition of the highly specific fine motor dental skills.

METHODS

A scoping review was performed to broadly map the available evidence and to detect knowledge gaps on the utility of haptic dental simulation in early dental training. The review is reported using the PRISMA-ScR guidelines. Eight bibliographic databases were searched: Web of Science, Scopus, MEDLINE via PubMed, Cochrane library, CENTRAL, ERIC, IEEE Xplore, and TRIP. Charted data were reported by clustering results according to study characteristics, research themes, research purpose, and type of validity evidence identified.

RESULTS

The review process resulted in the inclusion of 36 studies published between 2009 and 2020. The majority of the studies were cross-sectional in design with short-term evaluation data. Of the studies included, 64% investigated commercially available haptic simulators, while 36% investigated experimental haptic simulators. The research themes identified were skill acquisition and transfer, task-specific haptic training, trainee level discrimination, feedback, subjective user evaluation, performance prediction, and human factors in haptic training.

CONCLUSION

Short-term evaluation evidence from reviewed studies indicates the usefulness of the haptic simulators in early dental training. They complement the existing phantom head simulators by offering qualitatively different features. Further empirical research is needed to investigate the long-term impact of training with haptic dental simulators, to improve the availability of validation evidence and to enhance the results generalizability.

Validation of virtual reality orbitometry bridges digital and physical worlds

Clinical science and medical imaging technology are traditionally displayed in two dimensions (2D) on a computer monitor. In contrast, three-dimensional (3D) virtual reality (VR) expands the realm of 2D image visualization, enabling an immersive VR experience with unhindered spatial interaction by the user. Thus far, analysis of data extracted from VR applications was mainly qualitative. In this study, we enhance VR and provide evidence for quantitative VR research by validating digital VR display of computed tomography (CT) data of the orbit. Volumetric CT data were transferred and rendered into a VR environment. Subsequently, seven graders performed repeated and blinded diameter measurements. The intergrader variability of the measurements in VR was much lower compared to measurements in the physical world and measurements were reasonably consistent with their corresponding elements in the real context. The overall VR measurements were 5.49% higher. As such, this study attests the ability of VR to provide similar quantitative data alongside the added benefit of VR interfaces. VR entails a lot of potential for the future research in ophthalmology and beyond in any scientific field that uses three-dimensional data.

The effect of three-dimensional visualisation on performance in endoscopic sinus surgery: A clinical training study using surgical navigation for movement analysis in a randomised crossover design

OBJECTIVES

Endoscopic imaging techniques and endoscopic endonasal surgery (EES) expertise have evolved rapidly. Only few studies have assessed the effect of three-dimensional (3D) endoscopy on endoscopic sinus surgery (ESS). The present study aimed to objectively and subjectively assess the additional value of 3D high-definition (HD) endoscopy in ESS.

DESIGN

A randomized crossover study of endoscopic surgery performance, using five ESS tasks of varying complexity, performed on Thiel embalmed human specimens.

SETTING

Simulated surgical environment.

PARTICIPANTS

Thirty participants, inexperienced in ESS.

MAIN OUTCOME MEASURES

Performance was assessed using video imaging, surgical navigation and questionnaires. Main outcome measures were as follows: efficiency (defined by time to task completion), distance covered inside the nose, average velocity towards target, accuracy (measured by error rate), and subjective assessment of endoscope characteristics.

RESULTS

During ESS tasks, both efficiency and accuracy did not differ significantly between 2D HD and 3D HD endoscopy. Subjectively, imaging characteristics of the 3D HD endoscope were rated significantly better.

CONCLUSIONS

ESS performance of inexperienced participants was not significantly improved by the use of 3D HD endoscopy during ESS tasks, although imaging characteristics of the 3D HD endoscope were rated significantly better. Surgical field characteristics and surgical techniques are likely to influence any additional value of 3D HD endoscopy.

Early assessment with a virtual reality haptic simulator predicts performance in clinical practice

Background

Prediction of clinical training aptitude in medicine and dentistry is largely driven by measures of a student’s intellectual capabilities. The measurement of sensorimotor ability has lagged behind, despite being a key constraint for safe and efficient practice in procedure-based medical specialties. Virtual reality (VR) haptic simulators, systems able to provide objective measures of sensorimotor performance, are beginning to establish their utility in facilitating sensorimotor skill acquisition, and it is possible that they may also inform the prediction of clinical performance.

Methods

A retrospective cohort study examined the relationship between student performance on a haptic VR simulator in the second year of undergraduate dental study with subsequent clinic performance involving patients 2 years later. The predictive ability was tested against a phantom-head crown test (a traditional preclinical dental assessment, in the third year of study).

Results

VR scores averaged across the year explained 14% of variance in clinic performance, while the traditional test explained 5%. Students who scored highly on this averaged measure were ~10 times more likely to be high performers in the clinical crown test. Exploratory analysis indicated that single-trial VR scores did not correlate with real-world performance, but the relationship was statistically significant and strongest in the first half of the year and weakened over time.

Conclusions

The data demonstrate the potential of a VR haptic simulator to predict clinical performance and open up the possibility of taking a data-driven approach to identifying individuals who could benefit from support in the early stages of training.

Functional significance of stereopsis in professional table-tennis players

BACKGROUND

Stereopsis is the most important part of depth perception, especially in athletic population. At present, there are few studies on how to comprehensively evaluate athletes' stereoscopic function and how the impairment of stereoscopic function affects sports performance.

METHODS

Twenty-two professional table-tennis players from Sichuan Province Team were recruited as player group and 23 age-matched students were recruited as the controls. All subjects were measured the habitual visual acuity, best corrected visual acuity, dominant eye, retinoscopy and three stereo acuity tests. Both groups completed two motor skills tasks: Purdue Pegboard and beads threading with habitual binocular viewing and monocular viewing by covering dominant eye. In addition, the player group was asked to complete a brief questionnaire and catch balls served by the auto table-tennis machine under two viewing conditions.

RESULTS

The player group had better stereo acuity with median values of 60, 25 and 40 arc sec in TNO, Butterfly, and Frisby tests, respectively. There had statistically correlations between stereo acuity and two motor skills tasks. Both the two tasks were statistically significant different between binocular and monocular viewings in both groups. The player group had better performance on Purdue Pegboard task with binocular viewing (16±1.1, P=0.006) compared to the control group, while no statistical difference was found under monocular condition in beads threading task. In player group, the brief questionnaire demonstrated very negative feeling of players under monocular viewing and the number of catching balls had statistically significant difference between binocular (9.9±0.3) and monocular (6.9±1.6) viewings (P<0.001).

CONCLUSIONS

Stereopsis plays an important role in sports performance, the stereo tests combined with Purdue pegboard can be used to evaluate athletes' stereoscopic function comprehensively.

Drilling into the functional significance of stereopsis: the impact of stereoscopic information on surgical performance

Purpose

One suggested advantage of human binocular vision is the facilitation of sophisticated motor control behaviours via stereopsis – but little empirical evidence exists to support this suggestion. We examined the functional significance of stereopsis by exploring whether stereopsis is used to perform a highly skilled real‐world motor task essential for the occupational practice of dentistry.

Methods

We used a high fidelity virtual reality simulator to study how dentists’ performance is affected by the removal of horizontal retinal image disparities under direct and indirect (mirror) observation. Thirteen qualified dentists performed a total of four different dental tasks under non‐stereoscopic and stereoscopic vision conditions, with two levels of task complexity (direct and indirect observation) using a virtual reality dental simulator.

Results

Depth related errors were significantly higher under non‐stereoscopic viewing but lateral errors did not differ between conditions. Indirect observation led to participants drilling less of the target area compared to direct viewing, but this did not interact with the stereopsis manipulation.

Conclusions

The data confirm that dental practitioners use stereopsis and its presence results in improved dental performance. It remains to be determined whether individuals with stereo‐deficits can compensate adequately. Nevertheless, these findings suggest an important role for stereopsis within at least one occupation and justify the design of simulators with 3D displays.