Loss Of Depth Perception Research Articles

Altered Brain Structure and Spontaneous Functional Activity in Children With Concomitant Strabismus.

Strabismus occurs in about 2% of children and may result in amblyopia or lazy eyes and loss of depth perception. However, whether/how long-term strabismus shapes the brain structure and functions in children with concomitant strabismus (CS) is still unclear. In this study, a total of 26 patients with CS and 28 age-, sex-, and education-matched healthy controls (HCs) underwent structural and resting-state functional magnetic resonance imaging examination. The cortical thickness and amplitude of low-frequency fluctuation (ALFF) were calculated to assess the structural and functional plasticity in children with CS. Compared with HCs group, patients with CS showed increased cortical thickness in the precentral gyrus and angular gyrus while decreased cortical thickness in the left intraparietal sulcus, parieto-occipital sulcus, superior and middle temporal gyrus, right ventral premotor cortex, anterior insula, orbitofrontal cortex, and paracentral lobule. Meanwhile, CS patients exhibited increased ALFF in the prefrontal cortex and superior temporal gyrus, and decreased ALFF in the caudate and hippocampus. These results show that children with CS have abnormal structure and function in brain regions subserving eye movement, controls, and high-order cognitive functions. Our findings revealed the structural and functional abnormalities induced by CS and may provide new insight into the underlying neural mechanisms for CS.

An Endoscopic Transcanal Transpromontorial Approach for Vestibular Schwannomas using a Computer-Based Three-Dimensional Imaging System.

A 2D monocular endoscope has been used in transcanal transpromontory vestibular schwannoma surgery instead of craniotomy. However, the absence of depth perception is the limitation of this approach. With the loss of depth perception, the surgeon will be not able to perform delicate and particularly complicated surgery. A binocular endoscope has been developed to provide stereoscopic vision with better depth perception for complicated anatomic structures and has been applied in some endoscopic surgeries. However, the diameter of the endoscope is a limitation in the performance of transcanal otologic surgeries. A small diameter endoscope facilitates easier surgery in a restricted space. A computer-based 3D imaging system can obtain 3D images in real-time using a small monocular endoscope. In this study, to evaluate the feasibility of a computer-based 3D imaging system for endoscopic lateral skull base surgery, we applied this 3D imaging system in a transcanal transpromontorial approach in two patients with vestibular schwannomas. The surgical procedure was completed without complication in these two cases. There was no mortality, perioperative complications, nor notable postoperative complications. Using this computer-based 3D imaging system, a better depth perception and stereoscopic vision was observed compared to a conventional 2D endoscope. The improvement in depth perception offers superior management of the complicated surgical anatomy.

Development of GUI for Detetection of Eye Disorders in Infants

Strabismus is one of the most common vision diseases in which the eyes do not properly align with each other when looking at an object. The condition may be present occasionally or constantly and if it is present during a large part of childhood, it may result in amblyopia or loss of depth perception. In contrast to manual diagnosis, automatic recognition can significantly reduce labor cost and increase diagnosis efficiency. In this paper, we propose to detect ICD-10-CM Code H50.9 unspecified strabismus using CNN and Image Processing techniques. There are four types of strabismus namely exotropia, esotropia, hypertropia and hypotropia which we aim to detect. We furthermore aim to introduce a GUI particularly into pediatric ophthalmology where obtaining relevant diagnostic information is taxing.

Concentric Tube Robots for Minimally Invasive Surgery: Current Applications and Future Opportunities

Minimally Invasive Surgery (MIS) evolved as an alternative to open surgical approaches, and resulted in reduced surgical trauma and faster recovery. However, the confined workspace, loss of depth perception, compromised hand-eye coordination, as well as extended learning curves precluded the surgeons from adapting this approach in all cases. Unlike rigid robots that are characterized with mechanical rigidity and limited degrees-of-freedom (DOFs), continuum robots were developed mainly for interventional medicine. A special class of continuum robots are Concentric Tube Robots (CTRs), that have diameters comparable to those of catheters and steerable needles. Since their introduction, huge effort has been dedicated to the kinematic modelling and real-time control. Due to their intrinsic actuation capability, miniaturization potential and controllable mechanical properties, they have been adopted for different surgical applications. Experimental tests based on phantom and cadaveric studies were performed to prove their feasibility. This review encompasses the generic design, modelling and control methods of CTRs. It also addresses, in detail, their different surgical applications. Finally, related main research limitations and future opportunities are briefly discussed.

Practical Aspects and Avoidance of Complications in Microendoscopic Spine Surgeries: A Review.

Although the indications for endoscopic procedures have increased in recent times, there are also some limitations. This review discusses the practical points to prevent and treat complications in microendoscopic spine surgery. A literature search was conducted for the relevant articles after a topic search on PubMed, Google Scholar, and Medline. The review is based on the experience of 1,574 spinal endoscopic procedures performed by the senior author. Advantages of endoscopic surgery include better visualization, panoramic vision, and the ability to work around corners. Limitations with endoscopic procedures include proximal blind areas, obstruction in instrument handling due to a narrow corridor, disorientation, frequent lens fogging, loss of depth perception, and difficulty in achieving hemostasis, leading to complications and longer operative time during the learning curve. Surgeons need to learn endoscopic skills in addition to microsurgical ones to perform microendoscopic procedures properly. Attending live workshops, watching operative videos, visiting various departments, watching an experienced and accomplished endoscopic surgeon, proper case selection, a multidisciplinary team approach, practicing on models, hands-on cadaveric workshops, laboratory training, and simulators can improve results and shorten the learning curve.

Endoscope Holders in Cranial Neurosurgery: Part 2-An International Survey.

Following a previous systematic review of currently available endoscope holders (EHs), we aspired to detect trends, task-specific preferences, and pitfalls of EH in various cranial neuroendoscopic procedures. A questionnaire was disseminated to members of the International Federation of Neuroendoscopy. The questionnaire evaluated indications and pitfalls of EH in different applications, in particular, differentiating between intraventricular and skull base endoscopy, as well as subcategories of these 2 main fields. Furthermore, interest or involvement in research projects on EH was investigated. Fifty-two surgeons responded, with a broad geographic distribution represented. Most (54%) do not routinely use EH. Others use holders mainly for intraventricular rather than skull base procedures. Most surgeons (96%) regularly work with a co-surgeon. Reported weaknesses of EH included crude movements, downward drift, loss of depth perception, lack of flexibility, iatrogenic injury, cost, and bulky construct. There is still a lack of consensus on surgical indications. Tumor resections in intraventricular and skull base regions (not small sellar tumors) seem to stand out as good, widely accepted indications. Although EH have a role in cranial neuroendoscopy, their use seems limited and their technical features are regarded as suboptimal by most neuroendoscopists. Weaknesses and implications were detected in all application categories (skull base and intraventricular) but may vary slightly. Potentially, separate systems with distinct features may be required for skull base versus intraventricular surgery. There is a need for further evolution of EH, which could lead to a future paradigm shift in their use.

An investigation into discharge, visual perception, and appearance concerns of prosthetic eye wearers

ABSTRACTWe investigate prosthetic eye wearers’ initial and current concerns about mucoid discharge, visual perception, and appearance, and the reasons for their concerns. A retrospective, cross-sectional study of private practice patients was designed. Participants were 217 experienced prosthetic eye wearers, aged at least 16 years. An anonymous questionnaire was e-mailed or mailed to participants. Descriptive and inferential statistics were used to investigate differences or correlations between variables. Content analysis was used to analyze participants’ open responses. Participants were equally concerned about discharge, visual perception, and appearance during the first three months following eye loss and at least 2 years later, even though their concerns decreased. Older participants were less concerned about appearance, while females were more concerned about current discharge and appearance. The greater the frequency and volume of discharge, the greater was the concern. Participants’ initial discharge concern was due to a negative interpretation of what it meant, but later, it was due to discomfort from wiping, and how discharge looked to others. Loss of depth perception and reduced visual range were equally concerning. Initial appearance concerns related to disguisability of the prosthesis, but over time, changes to the socket and eyelids became more important. Loss of self-image is commonly considered to be the major concern of anophthalmic patients, but discharge and visual perception concerns are of equal importance. Reasons given for these concerns provide greater insight into patients’ personal experience of eye loss.

Warming up with endotrainer prior to laparoscopic cholecystectomy

Abstract Background Laparoscopic cholecystectomy is a safe and effective treatment and remains the gold standard in patients with benign disease. However it presents difficulties such as: the limited movement range of the instruments, the loss of depth perception, haptic feedback and the fulcrum effect. Previous training can optimise surgical performance in patients to master basic skills. Objective Assess the effectiveness of surgeons warming up with an endotrainer before performing laparoscopic cholecystectomy. Material and methods Single-blind controlled clinical trial with 16 surgeons who performed 2 laparoscopic cholecystectomies, the first according to standard practice and the second with warm-up comprising 5 MISTELS system exercises. Patient and surgeon demographics were recorded, in addition to findings and complications during and after surgery for each procedured. Results We found a decrease in surgical time of 76.88 (±18.87) minutes in the group that did not warm up to prior to surgery compared with 72.81 (±35.5) minutes in the group with warm-up ( p = 0.0196). In addition, increased bleeding occurred in the procedures performed with warm-up 31.25 (±30.85) ml compared with the group that had no warm-up 23.94 (±15.9) ( p = 0.0146). Conclusion Performing warm up on a MISTELS system endotrainer before performing laparoscopic cholecystectomy reduces the operating time of surgery for all surgeons. Surgery bleeding increases in operations performed by surgeons with less experience in laparoscopic surgery.

Sa1071 A Look in the Right Place: Optimal Gaze Strategy for Colonoscopy: A Systematic Review and Comparative Analysis

Recent research has revealed differences in the gaze control strategies of experienced and novice laparoscopic surgeons. When acquiring endoscopic techniques, the gastroenterologists must overcome environmental constraints on visuomotor control, such as loss of depth perception, poor tactile feedback, and the use of long instruments that amplify movement error and exhibit a fulcrum effect. Little is known about the visual gaze pattern (VGP) that may impact colonoscopy effectiveness. This study examined the optimal gaze strategy for colonoscopy and effect on adenoma detection through a systematic review and comparative analysis.

Three-dimensional laparoscopy: Principles and practice.

The largest challenge for laparoscopic surgeons is the eye–hand coordination within a three-dimensional (3D) scene observed on a 2D display. The 2D view on flat screen laparoscopy is cerebrally intensive. The loss of binocular vision on a 2D display causes visual misperceptions, mainly loss of depth perception and adds to the surgeon's fatigue. This compromises the safety of laparoscopy. The 3D high-definition view with great depth perception and tactile feedback makes laparoscopic surgery more acceptable, safe and cost-effective. It improves surgical precision and hand–eye coordination, conventional and all straight stick instruments can be used, capital expenditure is less and recurring cost and annual maintenance cost are less. In this article, we have discussed the physics of 3D laparoscopy, principles of depth perception, and the different kinds of 3D systems available for laparoscopy. We have also discussed our experience of using 3D laparoscopy in over 2000 surgeries in the last 4 years.

Calentamiento en endotrainer previo a colecistectomía laparoscópica

BackgroundLaparoscopic cholecystectomy is a safe and effective treatment and remains the gold standard in patients with benign disease. However it presents difficulties such as: the limited movement range of the instruments, the loss of depth perception, haptic feedback and the fulcrum effect. Previous training can optimize surgical performance in patients to master basic skills. ObjectiveAssess the effectiveness of surgeons warming up with an endotrainer before performing laparoscopic cholecystectomy. Material and methodsSingle-blind controlled clinical trial with 16 surgeons who performed 2 laparoscopic cholecystectomies, the first according to standard practice and the second with warm-up comprising 5 MISTELS system exercises. Patient and surgeon demographics were recorded, in addition to findings and complications during and after surgery for each procedured. ResultsWe found a decrease in surgical time of 76.88 (±18.87) minutes in the group that did not warm up to prior to surgery compared with 72.81 (±35.5) minutes in the group with warm-up (p=0.0196). In addition, increased bleeding occurred in the procedures performed with warm-up 31.25 (±30.85) ml compared with the group that had no warm-up 23.94 (±15.9) (p=0.0146). ConclusionPerforming warm up on a MISTELS system endotrainer before performing laparoscopic cholecystectomy reduces the operating time of surgery for all surgeons. Surgery bleeding increases in operations performed by surgeons with less experience in laparoscopic surgery.

Laser visual guidance versus two-dimensional vision in laparoscopy: a randomized trial

BackgroundDuring laparoscopy, the surgeon’s loss of depth perception and spatial orientation is problematic. Laser visual guidance (LVG) is an innovative technology that improves depth perception to enhance the visual field. In this trial, we examined the effect of LVG on surgical novices’ motor skills, quality of task performance, and cognitive workload.MethodsWe designed a randomized controlled trial following the CONSORT statement. Thirty-two surgical novices completed the Training and Assessment of Basic Laparoscopic Techniques (TABLT) test. The first attempt allowed participants to familiarize themselves with the exercises. We then randomized the participants, and they completed a test session using either LVG or conventional two-dimensional vision.ResultsWe found no significant difference between using the LVG tool and conventional 2D vision; however, both the mean completion time and movements used were less in the LVG group: Mean time used in the LVG group was 1288 s (95 % CI 1188–1388) versus 1354 s (95 % CI 1190–1518) (p = 0.45); mean angular path length used in the LVG group was 24,049° (95 % CI 20,761–27,336) versus 26,014° (95 % CI 22,059–29,970) (p = 0.42); mean path length in the LVG group was 4560 cm (95 % CI 3971–5,149 cm) versus 5062 cm (95 % CI 4328–5797), (p = 0.26). Moreover, the mean TABLT performance score was higher in the LVG group compared with the 2D group, although not significant: 379 (95 % CI 352–405) versus 338 (95 % CI 288–387) (p = 0.14). No significant difference was found between the groups’ cognitive workloads.ConclusionWe found no significant improvement of laparoscopic motor skills when using LVG, although a tendency toward improved performance was seen. LVG could have the potential to help novice surgeons acquire basic laparoscopic; however, further development of the concept and validation is needed to confirm this.

Clinical outcomes of three-dimensional versus two-dimensional laparoscopic surgery for gastric cancer: A single center, prospective, randomized trial—An interim report.

53 Background: Laparoscopic surgery is more challenging compared with open surgery, in part because surgeons must operate in three-dimensional (3D) space through a two-dimensional (2D) projection on a monitor, which results in loss of depth perception. To counter this problem, 3D imaging for laparoscopic was developed. However, there is limited evidence regarding its efficacy and safety. We therefore conducted a phase III, single center, prospective, randomized study to validate the efficacy and safety of 3D laparoscopic gastrectomy for gastric cancer compared with 2D laparoscopic surgery. Methods: The eligible criteria were pathologically-proven adenocarcinoma, 18 to 75 years of age, no history of other malignant tumor, chemotherapy, or radiotherapy, and clinical stage T1-4aN0-3M0 with R0 resection. The primary end point was to determine whether there is a difference in operation time between the two groups. The morbidity and mortality were compared to evaluate the safety of this trial. Results: A total of 196 patients were randomized (97 cases in 3D Group; 99 cases in 2D Group) between January 1, 2015 and August 31, 2015. There were no significant differences between the two groups in clinicopathological characteristics. The mean number of retrieved lymph nodes was similar in the 3D and 2D groups (35.6±14.1 vs. 36.1±13.5 per case). The operation time was similar in 3D and 2D groups (183.6±34.1 vs. 180.0±37.2 min). The blood loss in 3D Group was 59.6±45.6 ml, which was less than that in 2D Group (69.9±62.4 ml) without statistically different. There were no significant differences in times to resumption of activities, first flatus, resumption of soft diet, and post-operative stay between the two groups (P > 0.05, respectively). The morbidity of the 3D and 2D groups were 21.6% (21/97) and 17.1% (17/99), respectively (P = 0.428). There was no patient died during the postoperative stay in both groups. Conclusions: 3D laparoscopic gastrectomy is a safe and feasible procedure for gastric cancer. However, compared with 2D group, there was no so much benefit from 3D laparoscopic gastrectomy for gastric cancer. Clinical trial information: NCT02327481.

Endoscope Holders in Cranial Neurosurgery: Part I—Technology, Trends, and Implications

Cranial neuroendoscopy is becoming increasingly popular. Endoscopes may be used free-hand or with endoscope holders (EH). The aim of this paper is to summarize the evolution of EH and attempt an overview of currently available devices, features, and usage, identifying weaknesses and focusing on feasibility. A systematic review was conducted on Pubmed, OvidSP, Ebsco, and Google Scholar. Targeted search through cross-references was also implemented, followed by personal contacts, interviews, company websites, and operating manuals. A pilot survey was performed to acquire an impression of the current state of usage. This was conducted by approaching surgeons from several countries via e-mail and online through a neurosurgical exchange forum. A more extensive survey will follow as Part II. EH may be divided into manual and pneumatic. The use of micromanipulators is sometimes implemented. Different characteristics have been described, such as pneumatic, mechanical, friction, micromanipulator, robotic, hybrid, air-locking, and voice-control. Twenty eight surgeons responded. The majority (75%) do not routinely use EH. The rest use EH mainly for intraventricular rather than skull base procedures. Nearly all surgeons (96%) stated using a second surgeon regularly. Reported weaknesses included crude movements, downward drift, loss of depth perception, lack of flexibility, iatrogenic injury, cost, and bulky construction. Although EH have a role in neuroendoscopy, their use seems to be limited and their features regarded as suboptimal. There are no clear indications regarding the procedures that should be performed using EH. Many factors affect the implication of EH, including safety, type of surgery, surgeon's preference, and mechanical properties.

Comparative study of microscopic-assisted and endoscopic-assisted myringoplasty

This study was conducted to determine the advantages and disadvantages of the endoscope as compared to microscope in myringoplasty surgery and to compare the results of both groups. The cases for this study were taken from the inpatient cases of the Department of Otorhinolaryngology, in tertiary care hospital for prospective study during the period of January 2012–August 2013. Thirty cases were taken for the study under each group. All patients in both groups were followed up for a minimum of 6 months. Final assessment of tympanic membrane and hearing was done at 6 months postoperation. Subjective and objective assessment of scar was done at 6 months postoperation. In our study, the success rate of endoscope-assisted myringoplasty was comparable to that of microscope-assisted myringoplasty. Regarding cosmosis endoscope produced superior results. The wide angle, telescopic, magnified view of the endoscope overcomes most of the disadvantages of the microscope. Loss of depth perception and one-handed technique are some of the disadvantages of the endoscope that can be easily overcome with practice.

Loss of depth perception by genetic silencing of ipsilateral retinal projections

Loss of depth perception by genetic silencing of ipsilateral retinal projections

Image-based laparoscopic bowel measurement.

Minimally invasive interventions offer benefits for patients, while also entailing drawbacks for surgeons, such as the loss of depth perception. Thus estimating distances, which is of particular importance in gastric bypasses, becomes difficult. In this paper, we propose an approach based on stereo endoscopy that segments organs on-the-fly and measures along their surface during a minimally invasive interventions. Here, the application of determining the length of bowel segments during a laparoscopic bariatric gastric bypass is the main focus, but the proposed method can easily be used for other types of measurements, e.g., the size of a hernia. As input, image pairs from a calibrated stereo endoscope are used. Our proposed method is then divided into three steps: First, we located structures of interest, such as organs and instruments, via random forest segmentation. Two modes of instrument detection are used. The first mode is based on an automatic segmentation, and the second mode uses input from the user. These regions are then reconstructed, and the distance along the surface of the reconstruction is measured. For measurement, we propose three methods. The first one is based on the direct distance of the instruments, while the second one finds the shortest path along a surface. The third method smooths the shortest path with a spline interpolation. Our measuring system is currently one shot, meaning a signal to begin a measurement is required. To evaluate our approach, data sets from multiple users were recorded during minimally invasive bowel measurements performed on phantoms and pigs. On the phantom data sets, the overall average error was [Formula: see text] on shorter pieces of bowel ([Formula: see text]5 cm) and [Formula: see text] on longer pieces ([Formula: see text]10 cm). On the porcine data sets, the average error was [Formula: see text]. We present and evaluate a novel approach that makes measuring on-the-fly during minimally invasive surgery possible. Furthermore, we compare different methods for determining the length of bowel segments. The only requirement for our approach is a calibrated stereo endoscope, thereby keeping the impact on the surgical workflow to a minimum.

The role of the posterior parietal cortex in stereopsis and hand-eye coordination during motor task behaviours.

The field of 'Neuroergonomics' has the potential to improve safety in high-risk operative environments through a better appreciation of the way in which the brain responds during human-tool interactions. This is especially relevant to minimally invasive surgery (MIS). Amongst the many challenges imposed on the surgeon by traditional MIS (laparoscopy), arguably the greatest is the loss of depth perception. Robotic MIS platforms, on the other hand, provide the surgeon with a magnified three-dimensional view of the environment, and as a result may offload a degree of the cognitive burden. The posterior parietal cortex (PPC) plays an integral role in human depth perception. Therefore, it can be hypothesized that differences in PPC activation between monoscopic and stereoscopic vision may be observed. In order to investigate this hypothesis, the current study explores disparities in PPC responses between monoscopic and stereoscopic visual perception to better de-couple the burden imposed by laparoscopy and robotic surgery on the operator's brain. Fourteen participants conducted tasks of depth perception and hand-eye coordination under both monoscopic and stereoscopic visual feedback. Cortical haemodynamic responses were monitored throughout using optical functional neuroimaging. Overall, recruitment of the bilateral superior parietal lobule was observed during both depth perception and hand-eye coordination tasks. This occurred contrary to our hypothesis, regardless of the mode of visual feedback. Operator technical performance was significantly different in two- and three-dimensional visual displays. These differences in technical performance do not appear to be explained by significant differences in parietal lobe processing.

Augmented Reality Navigation With Automatic Marker-Free Image Registration Using 3-D Image Overlay for Dental Surgery

Computer-assisted oral and maxillofacial surgery (OMS) has been rapidly evolving since the last decade. State-of-the-art surgical navigation in OMS still suffers from bulky tracking sensors, troublesome image registration procedures, patient movement, loss of depth perception in visual guidance, and low navigation accuracy. We present an augmented reality navigation system with automatic marker-free image registration using 3-D image overlay and stereo tracking for dental surgery. A customized stereo camera is designed to track both the patient and instrument. Image registration is performed by patient tracking and real-time 3-D contour matching, without requiring any fiducial and reference markers. Real-time autostereoscopic 3-D imaging is implemented with the help of a consumer-level graphics processing unit. The resulting 3-D image of the patient's anatomy is overlaid on the surgical site by a half-silvered mirror using image registration and IP-camera registration to guide the surgeon by exposing hidden critical structures. The 3-D image of the surgical instrument is also overlaid over the real one for an augmented display. The 3-D images present both stereo and motion parallax from which depth perception can be obtained. Experiments were performed to evaluate various aspects of the system; the overall image overlay error of the proposed system was 0.71mm.

The future: taking veterinary laparoscopy to the next level.

Laparoscopic surgery minimizes tissue trauma and speeds recovery, but its uptake into veterinary clinical practice has been slow. Laparoscopy is distinctly different from traditional open surgery and a reduced working area and loss of depth perception are among the challenges that the surgeon must get to grips with. Indeed, it is often lack of the necessary skills, rather than the cost of equipment, that presents the greatest obstacle. This article is aimed at practitioners keen to embrace minimally invasive surgery and advises on how to develop excellence in laparoscopic skills. It makes the case for simulation training and outlines methods that can be instituted in practice at low cost and with comparatively little time expenditure. It also describes technological advances that have already increased the success of veterinary 'keyhole' surgery, as well as those that look promising for the future. Simulation training has been an intense area of research and publication within the past 15 years. This article draws on that evidence base and the experience gained by the author and her research team, which is at the forefront of efforts to develop laparoscopic training for veterinarians.