High-definition Systems Research Articles

Multi-objective optimization via evolutionary algorithm (MOVEA) for high-definition transcranial electrical stimulation of the human brain

Designing a transcranial electrical stimulation (tES) strategy requires considering multiple objectives, such as intensity in the target area, focality, stimulation depth, and avoidance zone. These objectives are often mutually exclusive. In this paper, we propose a general framework, called multi-objective optimization via evolutionary algorithm (MOVEA), which solves the non-convex optimization problem in designing tES strategies without a predefined direction. MOVEA enables simultaneous optimization of multiple targets through Pareto optimization, generating a Pareto front after a single run without manual weight adjustment and allowing easy expansion to more targets. This Pareto front consists of optimal solutions that meet various requirements while respecting trade-off relationships between conflicting objectives such as intensity and focality. MOVEA is versatile and suitable for both transcranial alternating current stimulation (tACS) and transcranial temporal interference stimulation (tTIS) based on high definition (HD) and two-pair systems. We comprehensively compared tACS and tTIS in terms of intensity, focality, and steerability for targets at different depths. Our findings reveal that tTIS enhances focality by reducing activated volume outside the target by 60%. HD-tTIS and HD-tDCS can achieve equivalent maximum intensities, surpassing those of two-pair tTIS, such as 0.51 V/m under HD-tACS/HD-tTIS and 0.42 V/m under two-pair tTIS for the motor area as a target. Analysis of variance in eight subjects highlights individual differences in both optimal stimulation policies and outcomes for tACS and tTIS, emphasizing the need for personalized stimulation protocols. These findings provide guidance for designing appropriate stimulation strategies for tACS and tTIS. MOVEA facilitates the optimization of tES based on specific objectives and constraints, advancing tTIS and tACS-based neuromodulation in understanding the causal relationship between brain regions and cognitive functions and treating diseases. The code for MOVEA is available at https://github.com/ncclabsustech/MOVEA.

A ligament to identify the inferior limit of dissection in minimally invasive surgery for inguinal hernia

Background: Minimally invasive surgery has recently become the approach of choice for surgeons for inguinal hernia repair. Subsequent to excellent visualisation of the preperitoneal space by high definition and 4K systems during laparoscopy and robotic surgery, as well as increasing use of multi detector CT scans to visualise abdomen, our knowledge of the anatomy of the posterior view of inguinal region has been enhanced. However, recurrence after surgery for groin hernia continues to be an issue during its learning curve especially for laparoscopic repair. One cause for recurrence is the infolding of the mesh after its placement in the preperitoneal space. A reason for this is inadequate dissection of the peritoneal fold especially inferomedially. The peritoneum has to be dissected inferomedially till the point where the vas deferens turns medially. During the course of a randomised study done to compare Transabdominal preperitoneal mesh repair with Totally extraperitoneal mesh repair for Inguinal hernia, a structure was seen passing from the medial aspect of the vas deferens where it turned medially Methods: Prospective analysis of 106 consecutive patients who underwent laparoscopic inguinal hernia was done to identify the presence of such a ligament. Results: This study demonstrates the existence of a ligamentous structure from the vas deferens to the posterior lamina of subparietal layer of peritoneal space at the site where the vas turns medially. Conclusions: Identification and division of this ligament will help to ensure complete dissection of the peritoneum inferiorly as well as creaseless placement of mesh thus preventing recurrence.

Comparison of three-dimensional (3D) endovision system versus ultra-high-definition 4K endovision system in minimally invasive surgical procedures: a randomized-open label pilot study.

Experimental work comparing 3-Dimensional (3D) and 4K ultra-high-definition endovision system (4K) indicates that the latter with double the resolution of standard 2D high-definition systems may provide additional visual cues to compensate for the lack of stereoscopic vision. There is paucity of studies comparing 3D and 4K system in clinical settings. This randomized study compares 3D and 4K systems in three laparoscopic procedures of increasing complexity. 139 patients undergoing laparoscopic cholecystectomy (60 patients), transabdominal preperitoneal (TAPP) repair (49 patients) and laparoscopic Heller's cardiomyotomy with anti- reflux procedure (30 patients) between May 2018 and February 2020 were randomized to undergo surgery using either 3D or 4K systems. Primary objective was to measure total operative time. Secondary objectives were to compare workload perceived by surgeons using SURG-TLX and surgeon satisfaction score. Timings of key surgical steps and peri-operative course of the patients was also recorded. Data were analyzed using Stata Corp. 2015. Patients undergoing surgery with 3D and 4K systems were comparable in their clinical and demographic profiles. The mean total operative time in 3D and 4K groups was comparable in cholecystectomy (52.7 vs 56.2, p = 0.50), TAPP (63.8 vs 69.6, p = 0.25) and Heller's cardiomyotomy (124.7 vs 143.3, p = 0.14) with faster hiatal dissection in 3D group (8min, p = 0.02). Operative time was better in patients undergoing Heller's myotomy with Angle of His accentuation with 3D by 28min (p = 0.03). Total workload was similar in 3D and 4K groups in all the procedures but mental & physical demand was lower in 3D group in Heller's cardiomyotomy (p = 0.03, p = 0.01), Surgeon satisfaction score was comparable in all three procedures. Overall, 3D HD and 4K systems are comparable in performing laparoscopic cholecystectomy, TAPP and Heller's Cardiomyotomy. Hiatal dissection time, mental and physical task load was better with 3D in Heller's Cardiomyotomy.

Linked-color imaging versus white-light colonoscopy in an organized colorectal cancer screening program

Linked-color imaging (LCI), a new image-enhancing technology emphasizing contrast in mucosal color, has been demonstrated to substantially reduce polyp miss rate as compared with standard white-light imaging (WLI) in tandem colonoscopy studies. Whether LCI increases adenoma detection rate (ADR) remains unclear. Consecutive subjects undergoing screening colonoscopy after fecal immunochemical test (FIT) positivity were 1:1 randomized to undergo colonoscopy with LCI or WLI, both in high-definition systems. Insertion and withdrawal phases of each colonoscopy were carried out using the same assigned light. Experienced endoscopists from 7 Italian centers participated in the study. Randomization was stratified by gender, age, and screening round. The primary outcome measure was represented by ADR. Of 704 eligible subjects, 649 were included (48.9% men, mean age ± standard deviation, 60.8 ± 7.3 years) and randomized to LCI (n= 326) or WLI (n= 323) colonoscopy. The ADR was higher in the LCI group (51.8%) than in the WLI group (43.7%) (relative risk, 1.19; 95% confidence interval, 1.01-1.40). The proportions of patients with advanced adenomas and sessile serrated lesions were, respectively, 21.2% and 8.6% in the LCI arm and 18.9% and 5.9% in the WLI arm (not significant for both comparisons). At multivariate analysis, LCI was independently associated with ADR, along with male gender, increasing age, and adequate (Boston Bowel Preparation Scale score≥6) bowel preparation. At per-polyp analysis, the mean ± standard deviation number of adenomas per colonoscopy was comparable in the LCI and WLI arms, whereas the corresponding figures for proximal adenomas was significantly higher in the LCI group (.72 ± 1.2 vs .55 ± 1.07, P= .05) CONCLUSIONS: In FIT-positive patients undergoing screening colonoscopy, the routine use of LCI significantly increased the ADR. (Clinical trial registration number: NCT03690297.).

Comparison of three-dimensional and 4K imaging systems in novice surgeons: a cross-over study.

Laparoscopy has revolutionized the surgical field with the advent of minimally invasive techniques leading to smaller surgical wounds, enhanced recovery, early discharge from the hospital and early return to work. Since the initiation of three-dimensional (3D) systems, studies have failed to prove significant advantages over traditional two-dimensional systems which could be attributed to suboptimal image quality, poor illumination and high cost of earlier systems. Recent advances in stereoscopy have led to the introduction of high-definition (HD) systems with improvement in image quality in both two-dimensional and 3D systems. With HD and new 4K imaging system, the previous data are now obsolete. We devised a cross-over study using the Olympus 4K camera imaging system compared with the HD 3D systems using 40 novice surgeons with no prior surgical skills to perform standardized surgical tasks and the groups were crossed over to assess any difference in the learning curve with the imaging systems. The data showed a statistically significant difference in errors performed with the 3D imaging system with reduction in errors for passing needle through a ring, knot tying, cutting circle and touching circles with a needle. The time taken to perform those tasks was comparable except in knot tying where there was significant reduction in the time taken to tie knots with a P-value of <0.001 in both groups. The study showed no significant difference in the time to perform tasks. The precision of the tasks was significantly improved with the 3D systems.

Advanced imaging for detection and differentiation of colorectal neoplasia: European Society of Gastrointestinal Endoscopy (ESGE) Guideline - Update 2019.

1: ESGE suggests that high definition endoscopy, and dye or virtual chromoendoscopy, as well as add-on devices, can be used in average risk patients to increase the endoscopist's adenoma detection rate. However, their routine use must be balanced against costs and practical considerations.Weak recommendation, high quality evidence. 2: ESGE recommends the routine use of high definition systems in individuals with Lynch syndrome.Strong recommendation, high quality evidence. 3: ESGE recommends the routine use, with targeted biopsies, of dye-based pancolonic chromoendoscopy or virtual chromoendoscopy for neoplasia surveillance in patients with long-standing colitis.Strong recommendation, moderate quality evidence. 4: ESGE suggests that virtual chromoendoscopy and dye-based chromoendoscopy can be used, under strictly controlled conditions, for real-time optical diagnosis of diminutive (≤ 5 mm) colorectal polyps and can replace histopathological diagnosis. The optical diagnosis has to be reported using validated scales, must be adequately photodocumented, and can be performed only by experienced endoscopists who are adequately trained, as defined in the ESGE curriculum, and audited.Weak recommendation, high quality evidence. 5: ESGE recommends the use of high definition white-light endoscopy in combination with (virtual) chromoendoscopy to predict the presence and depth of any submucosal invasion in nonpedunculated colorectal polyps prior to any treatment. Strong recommendation, moderate quality evidence. 6: ESGE recommends the use of virtual or dye-based chromoendoscopy in addition to white-light endoscopy for the detection of residual neoplasia at a piecemeal polypectomy scar site. Strong recommendation, moderate quality evidence. 7: ESGE suggests the possible incorporation of computer-aided diagnosis (detection and characterization of lesions) to colonoscopy, if acceptable and reproducible accuracy for colorectal neoplasia is demonstrated in high quality multicenter in vivo clinical studies. Possible significant risks with implementation, specifically endoscopist deskilling and over-reliance on artificial intelligence, unrepresentative training datasets, and hacking, need to be considered. Weak recommendation, low quality evidence.

Is 3D faster and safer than 4K laparoscopic cholecystectomy? A randomised-controlled trial

BackgroundLaparoscopic surgery has well-established benefits for patients; however, laparoscopic procedures have a long and difficult learning curve, in large part due to the lack of stereoscopic depth perception. Developments in high-definition and stereoscopic imaging have attempted to overcome this. Three-dimensional high-definition (3D HD) systems are thought to improve operating times compared to two-dimensional high-definition systems. However their performance against new, ultra-high-definition (‘4K’) systems is not known.MethodsPatients undergoing laparoscopic cholecystectomy were randomised to 3D HD or 4K laparoscopy. Operative videos were recorded, and the time from gallbladder exposure to separation from the liver (minus on table cholangiogram) was calculated. Blinded video assessment was performed to calculate intraoperative error scores.ResultsOne hundred and twenty patients were randomised, of which 109 were analysed (3D HD n = 54; 4K n = 55). No reduction in operative time was detected with 3D HD compared to 4K laparoscopy (median [IQR]; 23.41 min [17.00–37.98] vs 20.90 min [17.67–33.03]; p = 0.91); nor was there any decrease observed in error scores (60 [56–62] vs 58 [56–60]; p = 0.27), complications or reattendance. Stone spillage occurred more frequently with 3D HD, but there were no other differences in individual error rates. Gallbladder grade and operating surgeon had significant effects on time to complete the operation. Gallbladder grade also had a significant effect on the error score.ConclusionsA 3D HD laparoscopic system did not reduce operative time or error scores during laparoscopic cholecystectomy compared with a new 4K imaging system.

Virtual chromoendoscopy for the real-time assessment of colorectal polyps in vivo: a systematic review and economic evaluation.

Current clinical practice is to remove a colorectal polyp detected during colonoscopy and determine whether it is an adenoma or hyperplastic by histopathology. Identifying adenomas is important because they may eventually become cancerous if untreated, whereas hyperplastic polyps do not usually develop into cancer, and a surveillance interval is set based on the number and size of adenomas found. Virtual chromoendoscopy (VCE) (an electronic endoscopic imaging technique) could be used by the endoscopist under strictly controlled conditions for real-time optical diagnosis of diminutive (≤ 5 mm) colorectal polyps to replace histopathological diagnosis. To assess the clinical effectiveness and cost-effectiveness of the VCE technologies narrow-band imaging (NBI), flexible spectral imaging colour enhancement (FICE) and i-scan for the characterisation and management of diminutive (≤ 5 mm) colorectal polyps using high-definition (HD) systems without magnification. Systematic review and economic analysis. People undergoing colonoscopy for screening or surveillance or to investigate symptoms suggestive of colorectal cancer. NBI, FICE and i-scan. Diagnostic accuracy, recommended surveillance intervals, health-related quality of life (HRQoL), adverse effects, incidence of colorectal cancer, mortality and cost-effectiveness of VCE compared with histopathology. Electronic bibliographic databases including MEDLINE, EMBASE, The Cochrane Library and Database of Abstracts of Reviews of Effects were searched for published English-language studies from inception to June 2016. Bibliographies of related papers, systematic reviews and company information were screened and experts were contacted to identify additional evidence. Systematic reviews of test accuracy and economic evaluations were undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Meta-analyses were conducted, where possible, to inform the independent economic model. A cost-utility decision-analytic model was developed to estimate the cost-effectiveness of VCE compared with histopathology. The model used a decision tree for patients undergoing endoscopy, combined with estimates of long-term outcomes (e.g. incidence of colorectal cancer and subsequent morbidity and mortality) derived from University of Sheffield School of Health and Related Research's bowel cancer screening model. The model took a NHS perspective, with costs and benefits discounted at 3.5% over a lifetime horizon. There were limitations in the data on the distribution of adenomas across risk categories and recurrence rates post polypectomy. Thirty test accuracy studies were included: 24 for NBI, five for i-scan and three for FICE (two studies assessed two interventions). Polyp assessments made with high confidence were associated with higher sensitivity and endoscopists experienced in VCE achieved better results than those without experience. Two economic evaluations were included. NBI, i-scan and FICE are cost-saving strategies compared with histopathology and the number of quality-adjusted life-years gained was similar for histopathology and VCE. The correct surveillance interval would be given to 95% of patients with NBI, 94% of patients with FICE and 97% of patients with i-scan. Limited evidence was available for i-scan and FICE and there was heterogeneity among the NBI studies. There is a lack of data on longer-term health outcomes of patients undergoing VCE for assessment of diminutive colorectal polyps. VCE technologies, using HD systems without magnification, could potentially be used for the real-time assessment of diminutive colorectal polyps, if endoscopists have adequate experience and training. Future research priorities include head-to-head randomised controlled trials of all three VCE technologies; more research on the diagnostic accuracy of FICE and i-scan (when used without magnification); further studies evaluating the impact of endoscopist experience and training on outcomes; studies measuring adverse effects, HRQoL and anxiety; and longitudinal data on colorectal cancer incidence, HRQoL and mortality. This study is registered as PROSPERO CRD42016037767. The National Institute for Health Research Health Technology Assessment programme.

Advanced imaging for detection and differentiation of colorectal neoplasia: European Society of Gastrointestinal Endoscopy (ESGE) Guideline

1 ESGE suggests the routine use of high definition white-light endoscopy systems for detecting colorectal neoplasia in average risk populations (weak recommendation, moderate quality evidence). 2 ESGE recommends the routine use of high definition systems and pancolonic conventional or virtual (narrow band imaging [NBI], i-SCAN) chromoendoscopy in patients with known or suspected Lynch syndrome (strong recommendation, low quality evidence). 2b ESGE recommends the routine use of high definition systems and pancolonic conventional or virtual (NBI) chromoendoscopy in patients with known or suspected serrated polyposis syndrome (strong recommendation, low quality evidence). 3 ESGE recommends the routine use of 0.1 % methylene blue or 0.1 % - 0.5 % indigo carmine pancolonic chromoendoscopy with targeted biopsies for neoplasia surveillance in patients with long-standing colitis. In appropriately trained hands, in the situation of quiescent disease activity and adequate bowel preparation, nontargeted, four-quadrant biopsies can be abandoned (strong recommendation, high quality evidence). 4 ESGE suggests that virtual chromoendoscopy (NBI, FICE, i-SCAN) and conventional chromoendoscopy can be used, under strictly controlled conditions, for real-time optical diagnosis of diminutive (≤ 5 mm) colorectal polyps to replace histopathological diagnosis. The optical diagnosis has to be reported using validated scales, must be adequately photodocumented, and can be performed only by experienced endoscopists who are adequately trained and audited (weak recommendation, high quality evidence). 5 ESGE suggests the use of conventional or virtual (NBI) magnified chromoendoscopy to predict the risk of invasive cancer and deep submucosal invasion in lesions such as those with a depressed component (0-IIc according to the Paris classification) or nongranular or mixed-type laterally spreading tumors (weak recommendation, moderate quality evidence). Advanced imaging techniques will need to be applied in specific patient groups in routine clinical practice and to be taught in endoscopic training programs.

3D Laparoscopic Monitors

Minimally invasive surgery (MIS) is a relatively new surgery comprising various procedures performed with special miniaturized instruments and imaging reproduction systems. Technological advances have made MIS an efficient, safe, and applicable tool for pediatric surgeons with unquestionable advantages. The recent introduction of three-dimensional (3D) high definition systems has been advocated in order to overcome some of the problems related to standard MIS visual limitations. This short paper recapitulates the necessity to minimize MIS visualization limitations and reports the characteristics of new laparoscopic 3D systems.

PTH-053 High Definition (HD) Versus Standard Definition (SD) White Light Endoscopy for Detecting Early Neoplasia (EN) in Barrett’S Oesophagus (BO) During Surveillance Endoscopy. is It Time to Change the Standard of Care?

IntroductionHD endoscopy systems provide superior image resolution. However, the utility of this new and more expensive technology in lesion detection has not been evaluated so far.Our aim was to assess...

A Step toward Nonrobotic Total Endoscopic Coronary Bypass Grafting: 40 Coronary Anastomoses in a Biomechanical Beating Heart Model

Nonrobotic total endoscopic coronary bypass grafting is commonly considered as technically too difficult. After endoscopic practicing in a simple box model, we questioned this statement in a more sophisticated training model. In a handmade chest model containing a mechanically actuated porcine heart, anastomoses between homologous vein and shunted anterior coronary artery were performed using Prolene 7-0 sutures or U-clips in 20 anastomoses each. Commercially available endoscopic instruments and exclusive two-dimensional endoscopic vision were used. As quality control, the procedures were recorded, flow was measured, indocyanine green dye angiograms were performed, vinylpolysiloxane endocasts were produced, and finally the anastomoses were assessed from the endothelial side. Three-dimensional computed tomographic reconstruction was explored for cast measuring. All anastomoses were completed successfully in a time of 51 ± 14 minutes (Prolene) and 48 ± 10 minutes (U-clips). Despite suboptimal equipment, a reproducible sequence of the procedure was established and documented. Improving surgical performance was reflected in a reduction in anastomotic leakage and time requirement. The quality assessment protocol showed a learning curve and problems itself, which are briefly discussed. A beating heart model is an adamant requirement of training for the technically demanding procedure of nonrobotic total endoscopic coronary bypass grafting. Refinement of the model and quality assessment as well as expansion of training to other regions of the heart should prepare for a cost-effective, broad-based clinical application of nonrobotic endoscopic techniques in coronary surgery. Available high-definition three-dimensional vision systems and the development of appropriate (articulating) instruments will make the procedure safer and quicker and will cut the learning curve.

Emerging technologies in endoscopic imaging.

Endoscopic imaging is in part responsible for the recent drop in deaths from gastrointestinal cancers and also for detecting pre-cancerous and non-cancerous conditions and allowing them to be treated effectively, although techniques are far from perfect. Endoscopic imaging has evolved considerably from fiber optic systems 50 years ago to high resolution and high definition systems used at present. Moreover, image enhancement using filters and processors has led to the technique of ‘electronic chromoendoscopy’ to visualize mucosal blood vessels and surface pit patterns clearly. Magnification by optical zoom or confocal laser microscopy has enabled real time diagnosis and ‘virtual histology’. These techniques have contributed to the early detection, assessment and treatment of various gastrointestinal pathologies. The focus of future research is directed towards molecular targeted imaging.

The Sense of Verisimilitude Has Different Spatial-Temporal Characteristics from Those Producing the Sense of Presence in the Evaluation Process of Audiovisual Contents

Realization of high-definition multimodal displays is keenly required for the advancement of information and communications technologies. As an index of high-definition display systems, the sense of presence has been widely investigated. Both theoretically and empirically such sense has been found to relate more dominantly to background components contained in a scene. In contrast, the appreciative role of foreground components in multimodal contents has not been investigated in detail. Therefore, we have been focusing on the sense of verisimilitude as another index. We recently studied how the sense of verisimilitude and the sense of presence were affected by temporal asynchrony between foreground audio-visual components of a Japanese garden and suggested that the sense of verisimilitude has significantly different characteristics from the sense of presence. To investigate whether this result would be valid more generally, we conducted an experiment using other audio-visual content, namely, a clip of wes...

Comparison of high definition with standard white light endoscopy for detection of dysplastic lesions during surveillance colonoscopy in patients with inflammatory bowel disease

IntroductionDysplasia in colonic inflammatory bowel disease (IBD) is often multifocal and flat, making it easy for significant lesions to be overlooked. Dye spraying the mucosal surface is believed to enhance...

The future of gynaecological endoscopy: from the work presented in the Free Communications during the ESGE Meeting in Florence October 2009

The senior author has had the privilege, along with almost 2,000 other delegates, of visiting the extraordinary ESGE meeting in Florence recently. The size of the turnout suggests that there is much going well in the field of gynaecological surgery. Minimal access techniques are now being used in every inhabited continent and in every type of health care system. There are more and more doctors of every nationality, colour and religion coming together with the single aim of improving the outcomes of surgical interventions in women. Reviewing the more than 400 talks, videos and posters presented at the ESGE meeting clearly demonstrates how minimal access techniques may be used for virtual every surgical intervention in gynaecology. We were also privileged to see enormous trade exhibitions with literally hundreds of new refined tools and devices, all designed to make surgically easier, more acceptable and above all safer for our patients. Whilst self-evidently good, this excess of technological virtuosity brings with it major concerns. The very number and variety of these advanced technologies can, in fact, be rather overwhelming. Many of these devices are extraordinarily expensive and in these difficult financial times it is ethically essential that, irrespective of the type of health care system in which we practice, we develop systems that not only work but work cost-effectively. With this concept in mind, we present here our personal review of some of the presentations from this important meeting. 1. Improved imaging techniques. From the first video laparoscopies, there has been a steady and dramatic improvement in the quality of the images we have. Better light sources and cameras have replaced dull, poorly illuminated pictures by images of consistent high quality. Three-chip cameras are now standard and increasingly high-definition systems are becoming available. The results of these technological advances were demonstrated by the extraordinary quality of many of the videos shown throughout the meeting. This is an area which is perhaps difficult to justify on formal cost effect analysis but in which there can be no compromise. To undertake surgery with inadequate vision is both impractical and unethical. Conversely, the better the image available, the better the definition of the anatomy and pathology and so the more precise and better the quality of the surgery should be. The images are now so good it is difficult to anticipate further meaningful improvements but it is probable that further miniaturisation will make the instruments easier to use, particularly in areas currently difficult to access. Three-dimensional imaging would also simplify dissection and suturing. Such systems have been tried previously but have been found to be heavy and difficult to use and to also produce unstable and nausea-producing images. It is likely that improvements in these systems may soon result in the wide availability of useful 3-D imaging systems. 2. Entry techniques. From the earliest days of laparoscopic surgery the safest and best method of entry into the abdominal cavity has been a matter of controversy. The data has been recently reviewed and extensively commented on in this journal (Sutton). Because of the relative infrequency of serious entry-related injury it has not been possible to do large enough trials to prove R. Garry (*) 94 Westgate, Guisborough TS14 6AP, UK e-mail: raygarry@btinternet.com

Beeinflussung von Netzhautdickenwerten durch antiangiogenetische Therapie bei altersbedingter Makuladegeneration

This study evaluated the impact of antiangiogenetic therapy on differences in central retinal thickness (CRT) as measured with two optical coherence tomography (OCT) systems from the same manufacturer. Data were obtained from a group of 20 patients with neovascular age-related macular degeneration before and after intravitreal treatment with ranibizumab. Imaging was performed using the Stratus and the high-definition (HD) Cirrus OCT systems. The mean CRT was revealed to be significantly lower as measured by OCT compared with HD-OCT before and after treatment (p<0.002). CRT differences varied more strongly before treatment than after treatment. A higher standard deviation was noted before treatment. The difference in the mean deviation of CRT measurements before and following antiangiogenetic therapy was highly significant. This study showed that differences in CRT measurements between different OCT systems were subject not only to technical differences but also to treatment effects of current antiangiogenetic strategies. These effects should be recognized because clinical studies increasingly define OCT parameters as primary or secondary outcome measures.

The effect of CyberDome, a novel 3-dimensional dome-shaped display system, on laparoscopic procedures

Laparoscopic surgeons require extended experience of cases to overcome the lack of depth perception on a two-dimensional (2D) display. Although a three-dimensional (3D) display was reported to be useful over two decades ago, 3D systems have not been widely used. Recently, we developed a novel 3D dome-shaped display (3DD) system, CyberDome. In the present study, a total of 23 students volunteered. We evaluated the effects of the 3DD system on depth perception and laparoscopic procedures in comparison with the 2D, a conventional 3D (3DP) or the 2D high definition (HD) systems using seven tasks. The 3DD system significantly improved depth perception and laparoscopic performance compared with the 2D system in six new tasks. We further found that the 3DD system shortened the execution time and reduced the number of errors during suturing and knot tying. The 3DD system also provided more depth perception than the 3DP and 2D HD systems. The novel 3DD system is a promising tool for providing depth perception with high resolution to laparoscopic surgeons.

Performance differences in laparoscopic surgical skills between true high-definition and three-chip CCD video systems

Laparoscopic surgery requires surgeons to rely on visual clues for discrimination among differing tissues and for depth of field on a two-dimensional screen. High definition (HD) provides a superior image. If there is a measurable advantage with HD television (TV), the increase in the cost of the technology would be justified. A digital three-chip CCD camera with a standard monitor (SD system) and a true HD camera (1,080 pixels) with a 16:9-ratio HD monitor (HD system) were compared in clinical and laboratory settings. Three experiments were performed: (1) subjective visual evaluation of the HD and SD systems during actual surgical cases, (2) subjective visual evaluation in a controlled laboratory surgical setting with simultaneous parallel recording, and (3) three laparoscopic surgical task evaluations in a laboratory setting, namely, task A (metric analysis of participants on the surgical simulator), task B (simple eye-hand coordination performance), and task C (knot tying). All 53 participants subjectively evaluated HD as superior to SD in the laboratory setting and during actual surgery. In task B, there was no significant difference between SD and HD (dominant hand: p = 0.19; nondominant hand: p = 0.07). In task C, the knot-tying time was significantly less when performed with HD (mean, 173 +/- 84 s vs 214 +/- 107 s; p = 0.003). Most importantly, subjects with less skill (more documented time required in the basic module on a surgical simulator) improved significantly in the knot-tying task with the HD system (R = 0.631; p = 0.005). All the participants preferred HD to SD. High definition significantly improved laparoscopic knot tying, which requires precise depth perception, proving that HD is more than just a pretty picture.

Excitonic prospects for UV

With the incandescent bulb beaten in terms of efficiency, and fluorescent lighting in its sights, wide bandgap semiconductors are looking for new territories to conquer. One direction to go is higher power and coherence, and blue-violet nitride-based laser diodes are now coming into commission in high-definition DVD (HD-DVD) and Blu-ray optical storage systems offering up to 25 gigabytes on a single layer. Another course is that towards shorter wavelengths – into the ultraviolet (UV).