An experimental and clinical study on the initial experiences of Brazilian vitreoretinal surgeons with heads-up surgery.

PURPOSE: To evaluate the initial experiences of several vitreoretinal surgeons in Brazil, both experienced and beginners, with a three-dimensional (3D) system, and to report the advantages and disadvantages of this technology. We also report surgical manipulations performed using the heads-up method in porcine eyes. For full-thickness idiopathic macular holes (MHs), we analyzed the times required for pars plana vitrectomy (PPV) and internal limiting membrane (ILM) rhexis by using traditional microscopy and 3D system, and to evaluate anatomical surgical results. METHODS: During experimental vitreoretinal surgery on porcine eyes, two retinal surgeons applied the heads-up method. In clinical surgery, 14 retinal surgeons performed almost all types of vitreoretinal surgeries in association with facectomy, Ahmed glaucoma valve implant, or minimally invasive glaucoma surgery using an iStent®. The Ngenuity® 3D Visualization System was digitally integrated with intraoperative optical coherence tomography, the Verion™ Image-Guided System, and an endoscope (with a modified GoPro® camera). To compare the 3D system with traditional microscopy, ergonomics, educational value, image sharpness, depth perception, field of view, advantages and disadvantages, and technical feasibility were assessed using a questionnaire. One year later, the 14 surgeons answered the same questionnaire again, in order to assess whether they became more comfortable or not with 3D. For treating MHs, four surgeons (surgeon 1, fellows 1, 2, 3) performed the total of 40 surgeries. Each one performed 10 surgeries (5 with traditional microscopy and 5 with 3D visualization). The completion time for PPV and ILM rhexis were determined by using both methods. RESULTS: In porcine eyes, disabling the color channels allowed better visualization of the ILM, either with Brilliant Blue G (BBG), indocyanine green chorioangiography (ICG), or açai dye; transillumination through the sclera was also better without a color channel, but visualization of the peripheral vitreous was better with a blue channel. Regarding clinical experience, the questionnaire responses showed that the respondents generally favored the heads-up method compared with traditional microscopy (p < 0.05); however, despite a slightly higher average score, the 3D system was not statistically significantly preferred in terms of technical feasibility (p = 0.1814). Answering again the same questionnaire 1 year later, the 14 surgeons felt more comfortable with 3D (p < 0.05). The type of surgery benefitting most from the 3D system was peeling of the ILM or epiretinal membrane (p < 0.001), and that receiving the least benefit was anterior segment surgery (p < 0.001). In addition, surgeons did not report benefits of color channels, preferring to disable it (p < 0.001). Comparisons between the average time for full PPV and ILM rhexis by using the two methods were non-significant, neither in each individual case of 3D surgery for each surgeon. Surgeon 1 had always been faster than his fellows. Thirty-six (90%) full-thickness MHs were successfully closed with one surgery. CONCLUSIONS: The 3D system was preferred to traditional microscopy. The 3D system was especially helpful for certain specific types of surgeries and served as an educational tool, having reduced illumination and allowing precise focusing. Concerning MH surgery, heads-up method was similar to traditional microscopy regarding length of time and anatomical surgical results. As a digital platform, it will be amenable to constant upgrades and may ultimately become the new standard for ophthalmic surgery.

Success Rates for Retinal Detachment Repair in Alberta: A Physician Learning Program Initiative.

OBJECTIVE: To identify primary surgical success rates for retinal detachment repair in Alberta and compare functional outcomes of methods of repair. METHODS: Data was retrospectively extracted from the Alberta Health Services Discharge Abstract Database and the National Ambulatory Care Reporting System for all patients diagnosed with retinal detachment and vitreoretinal procedures during the 2008/09 to 2012/13 fiscal years. RESULTS: Of the 5,433 surgeries for retinal detachment identified, 279 were excluded due to invalid provincial health numbers, unidentified procedure location, and/or treating physician other than an Alberta retina surgeon. The final analysis included 4,336 detachments in 4,020 patients. The average primary retinal detachment success rate was 84.9% (3,680/4,336). Primary success rates varied between vitrectomy only (84.9%, 2,149/2,532), vitrectomy and scleral buckle (85.5%, 818/957), and scleral buckle (84.4%, 702/832). CONCLUSIONS: Alberta retina surgeons have an average primary success rate of 84.9% (3,680/4,336) for repair of retinal detachments. This result is in keeping with other published retinal detachment success rate studies.

RESOLUTION, DEPTH OF FIELD, AND PHYSICIAN SATISFACTION DURING DIGITALLY ASSISTED VITREORETINAL SURGERY.

PURPOSE: To evaluate depth of field, lateral resolution, and image quality of a heads-up 3D visualization system for vitreoretinal surgery using physician survey and optical measurement outcomes. METHODS: Depth of field and lateral resolution were compared between the standard ocular viewing system and the digital 3D system at ×5, ×13, and ×18 magnification by 6 retinal surgeons. Optical techniques were used as well as a survey of surgeon impression. Surgeon impression surveys were performed after 6 weeks of surgical use of the device. RESULTS: Physician questionnaire survey scores for depth of field at high magnification were better for the digital 3D system and equivalent for all other categories. Measured lateral resolution was 36.7 mm and 16.6 mm at ×5 magnification (P < 0.001), 14.3 mm and 6.4 mm at ×13 magnification (P < 0.001), and 9.8 mm and 4.2 mm (P < 0.001) at ×18 magnification for the digital 3D and oculars, respectively. Measured depth of field was 4.00 mm and 6.78 mm at ×5 magnification (P = 0.027), 0.72 mm and 0.86 mm at ×13 (P = 0.311), and 0.28 mm and 0.40 mm at ×18 magnification (P = 0.235) for the oculars and digital 3D, respectively. CONCLUSION: Lateral resolution of the digital 3D system was half that of the ocular viewing system and there was some improvement in depth of field with the digital system. Surgeon impression suggested that the digital system was superior when evaluating depth of field at high magnification.

Autonomous Positioning of Eye Surgical Robot Using the Tool Shadow and Kalman Filtering.

Vitreoretinal surgery is one of the most difficult surgical operations, even for experienced surgeons. Thus, a master-slave eye surgical robot has been developed to assist the surgeon in safely performing vitreoretinal surgeries; however, in the master-slave control, the robotic positioning accuracy depends on the surgeon's coordination skills. This paper proposes a new method of autonomous robotic positioning using the shadow of the surgical instrument. First, the microscope image is segmented into three regions-namely, a micropipette, its shadow, and the eye ground-using a Gaussian mixture model (GMM). The tips of the micropipette and its shadow are then extracted from the contour lines of the segmented regions. The micropipette is then autonomously moved down to the simulated eye ground until the distance between the tips of micropipette and its shadow in the microscopic image reaches a predefined threshold. To handle possible occlusions, the tip of the shadow is estimated using a Kalman filter. Experiments to evaluate the robotic positioning accuracy in the vertical direction were performed. The results show that the autonomous positioning using the Kalman filter enhanced the accuracy of robotic positioning.

Diabetic Macular Edema: Emerging Strategies and Treatment Algorithms.

Diabetic macular edema (DME) is the most common cause of vision loss in diabetic patients, and its management is often a long process requiring frequent monitoring and therapeutic interventions. During the past several decades, numerous treatments have been developed for the treatment of DME. Although many of them have been found to be effective and safe, there is relatively little comparative data, and no established guidelines for the optimal treatment approach exist. In this chapter, the evolution of DME therapies is reviewed, and the current common practice patterns are discussed. Available data from clinical trials on the commonly used agents, as well as comparative studies and combination therapies are reviewed. Additionally, recent advances and novel treatment options that are currently being investigated are also discussed.

[Analysis of factors causing peripheral visual field defects after vitreomacular surgery].

As a result of the study analysis of potential causes of visual field defects (VFD) after vitreomacular surgery is performed. 110 cases are enrolled in the study: 81 patient with macular hole and 29 patients with epiretinal fibrosis. Correspondence of VFD to position of irrigation port including unusual inferior-nasal position was revealed as well as VFD absence in epiretinal fibrosis operated without air pump. VFD did not appear after lowering of air pump pressure by 15-20 mmHg. The cause of VFD after vitreomacular surgery is a mechanical damage of internal retinal surface by directed air/gas jet after total fluid exchange with too high pressure in an air pump. This complication is an easily preventable iatrogenic effect and may serve as one of quality criterion for this treatment procedure.

Incidence of unplanned return to the operating room following vitreoretinal surgery at a public teaching hospital.

PURPOSE: To determine the incidence of unplanned return to the operating room within 30 or 90 d following vitreoretinal surgery. METHODS: Hospital records of 431 patients undergoing vitreoretinal surgery at San Francisco General Hospital between 1 January 1998 and 31 December 2009 were reviewed to determine the incidence of unplanned reoperations. RESULTS: Unplanned reoperation occurred within 30 d in 22 cases (3.77%) and within 90 d in 56 cases (9.61%). CONCLUSIONS: This study establishes benchmarks for the rate of unplanned return to the operating room following vitreoretinal surgery at an urban teaching hospital. Measuring reoperation within 90 d may provide a useful quality improvement metric of short- and middle-term complications.

Impact of robotic assistance on precision of vitreoretinal surgical procedures.

PURPOSE: To elucidate the merits of robotic application for vitreoretinal maneuver in comparison to conventional manual performance using an in-vitro eye model constructed for the present study. METHODS: Capability to accurately approach the target on the fundus, to stabilize the manipulator tip just above the fundus, and to perceive the contact of the manipulator tip with the fundus were tested. The accuracies were compared between the robotic and manual control, as well as between ophthalmologists and engineering students. RESULTS: In case of manual control, ophthalmologists were superior to engineering students in all the 3 test procedures. Robotic assistance significantly improved accuracy of all the test procedures performed by engineering students. For the ophthalmologists including a specialist of vitreoretinal surgery, robotic assistance enhanced the accuracy in the stabilization of manipulator tip (from 90.9 µm to 14.9 µm, P = 0.0006) and the perception of contact with the fundus (from 20.0 mN to 7.84 mN, P = 0.046), while robotic assistance did not improve pointing accuracy. CONCLUSIONS: It was confirmed that telerobotic assistance has a potential to significantly improve precision in vitreoretinal procedures in both experienced and inexperienced hands.

Patient safety in vitreoretinal surgery: quality improvements following a patient safety reporting system.

AIMS: Vitreoretinal (VR) surgery is complex. Most clinical conditions that VR surgeons manage have a high risk for blindness or severe visual impairment. Reporting of patient safety incidents (PSI) in VR surgery was introduced at the Moorfields Eye Hospital (MEH) in the 1990s. We examine the role of PSI reporting in making VR surgery safer at our institution. METHODS: Qualitative review of PSIs from 1997 to 2009 at MEH, London, UK. RESULTS: Over the 13-year study period, 38 789 VR procedures were undertaken and 579 VR PSIs occurring in theatre or inpatient were reported. Mean rate of PSI reporting was 1.49% (range 0.12-3.35). In comparison, the mean rate of PSI reporting over the same period across all National Health Service ophthalmology in England was 0.59% (range 0.36-0.49). Overall, 0.9% of VR PSI resulted in 'Severe' harm, 11.6% in 'Moderate' harm and 87.5% in 'No' or 'Low' harm. 15 (2.6%) of PSIs directly resulted in a change in clinical practice, 13 of which occurred in the first half of the study period. 12 (3.6%) critical incidents were violations of pre-existing protocols and guidelines, eight of which occurred in the second half of the study period. 61 (10.9%) of PSIs fell into nine main error subtypes that contributed to a change in practice. The most common were ocular hypotony (2.9%), medical device failure (2.8%) and delay in VR surgery (1.2%). CONCLUSIONS: VR PSI reporting resulted in a change in clinical practice. Longitudinal analysis suggests an accompanying increase in patient safety.

Pneumatic retinopexy for retinal detachment associated with severe choroidal detachment.

PURPOSE: The purpose of this study was to evaluate the role of pneumatic retinopexy as an initial management of retinal detachment associated with hypotony, severe choroidal detachment, and vitritis. METHODS: Retrospective, interventional, noncomparative case series. We included nine eyes from nine patients (six women and three men) with retinal detachment associated with hypotony, severe choroidal detachment, and vitritis managed with pneumatic retinopexy (either SF6 or C3F8) as their initial management between January 1, 1992, and December 31, 2007. RESULTS: Hypotony and choroidal detachment were rapidly and significantly improved 1 to 3 days after pneumatic retinopexy in all patients. The extent of retinal detachment was decreased in five patients. After vitreoretinal surgery for these five patients, all had attached retina. Complete reattachment of the retina was noted in four patients after pneumatic retinopexy. Two of these patients did not require further surgery because the entire retina remained attached at 6 months and 16 months postoperatively. CONCLUSION: Pneumatic retinopexy is a useful initial procedure in managing retinal detachment associated with hypotony, severe choroidal detachment, and vitritis. By rapidly resolving the hypotony and choroidal detachments, it facilitates subsequent surgical repair of this complicated retinal detachment. In addition, complete retinal reattachment after pneumatic retinopexy alone was initially achieved in 33% of eyes.