A Submillimeter Continuous Variable Stiffness Catheter for Compliance Control

Minimally invasive robotic surgery often requires functional tools that can change their compliance to adapt to the environment and surgical needs. This paper proposes a submillimeter continuous variable stiffness catheter equipped with a phase-change alloy that has a high stiffness variation in its different states, allowing for rapid compliance control. Variable stiffness is achieved through a variable phase boundary in the alloy due to a controlled radial temperature gradient. This catheter can be safely navigated in its soft state and rigidified to the required stiffness during operation to apply a desired force at the tip. The maximal contact force that the catheter applies to tissue can be continuously modified by a factor of 400 (≈20 mN-8 N). The catheter is equipped with a magnet and a micro-gripper to perform a fully robotic ophthalmic minimally invasive surgery on an eye phantom by means of an electromagnetic navigation system.

OMNIDIRECTIONAL ILLUMINATION LIGHT SOURCE DEVICE: LED ORB Light System

Supplemental Digital Content is Available in the Text.

Murine Corneal Epithelial Wound Modeling

A murine model of corneal epithelial wounding can be performed using simple injury and imaging methods. Here, we describe the creation of a central corneal epithelial defect using mechanical debridement under ophthalmic microscopic visualization. Subsequent monitoring with vital dye application and slit-lamp bio microscopy (slit-lamp) is described in detail.

Clinical outcomes of trabecular microbypass stent (iStent) implantation in medically controlled open-angle glaucoma in the Korean population

To evaluate the safety and efficacy [intraocular pressure (IOP)-lowering effect and medication use] of a single trabecular microbypass stent (iStent; Glaukos Corp, San Clemente, CA) for medically controlled open-angle glaucoma.This retrospective case series included 42 eyes of 34 patients with medically controlled open-angle glaucoma with IOP less than 21 mm Hg. Clinical outcomes analyzed were IOP, medication use, corrected distance visual acuity (CDVA), and surgical complications. Surgical success was defined according to 4 criteria: IOP < 21 mm Hg without medication; IOP < 18 mm Hg without medication; IOP < 15 mm Hg without medications; and IOP < 18 mm Hg with or without medication. Patients were followed for a minimum of 6 months postoperatively.Mean IOP was reduced from 15.8 ± 2.8 mm Hg to 14.5 ± 2.8 mm Hg (P < .001), while mean number of medications decreased from 2.2 ± 1.2 to 0.8 ± 1.1 at final visit (P < .001). Surgical success rates were 78.6%, 61.9%, 57.1%, and 97.6% at 6 months and 78.6%, 59.5%, 52.4%, and 95.2% at final visits according to criteria A, B, C, and D. Meanwhile, 59.5% of patients were medication-free at their final visit. The relative risk of surgical failure by Criteria B and C was 4.337 (95% confidence interval: 1.799-10.454) and 3.717 (95% confidence interval: 1.516-9.116) times greater in the higher-medication group (3 or more preoperative medications), respectively. CDVA was significantly improved from 0.41 ± 0.10 to 0.09 ± 0.07 LogMAR in the combined phacoemulsification and iStent implantation group (P < .001). There was no case whose vision was threatened (vision loss of 2 or more lines) or who showed severe complications after surgery.Single trabecular microbypass stent implantation was effective in reducing IOP and medication usage in patients with open-angle glaucoma with a low preoperative IOP. Our results imply that it is more difficult to achieve low target IOP control in eyes with higher numbers of preoperative medications.

Microscope-integrated Intraoperative Optical Coherence Tomography for Anterior Segment Surgical Maneuvers

Purpose

To evaluate the potential value of microscope-integrated optical coherence tomography (MI-OCT) in anterior segment surgical maneuvers.

Methods

Twenty-four ophthalmology residents, who were randomly and evenly divided into two groups, performed four anterior segment surgical maneuvers (corneal tunnel, scleral tunnel, simple corneal suture, and corneal laceration repair) on porcine eyes with (group B) or without (group A) real-time MI-OCT feedback. All residents performed the maneuvers again without MI-OCT.

Results

Compared with group A, group B (with MI-OCT) showed better accuracy in the length/depth of the corneal tunnel and the length of the scleral tunnel. However, both groups showed similar performances in the depth of both the simple corneal suture and the corneal laceration suture. When both groups performed the maneuvers again without MI-OCT, group B still showed better results than group A for the length of both the corneal and scleral tunnels.

Conclusions

Primary results suggest that real-time MI-OCT images are valuable for some anterior segment surgical maneuvers and could be helpful in surgical training.

Translational Relevance

MI-OCT systems can be valuable in improving accuracy and decision making during anterior segment surgery and will be useful in surgical training.

Reducing the Number of Degrees of Freedom to Control an Eye Surgical Robot through Classification of Surgical Phases

This paper introduces an optimized input device workflow to control an eye surgical robot in a simulated vitreoretinal environment. The input device is a joystick with four Degrees of Freedom (DOF) that controls a six DOFs robot. This aim is achieved through a segmentation plan for an eye surgeon. In this study, the different surgical phases are defined while each phase includes their specific number of DOFs. The segmentation plan is divided into four surgical phases: Phase I: Approach with three DOFs; Phase II: Introduction with three DOFs; Phase III: Aim with 3+1 DOFs; and Phase IV: Injection with one DOF. Taking these phases into consideration, an eye surgical robot with six DOFs could be controlled through a joystick with only four DOFs intuitively. In this work we show that reducing the number of DOFs will decrease the complexity of the surgery with a robotic platform.

Fast 5DOF needle tracking in iOCT

PURPOSE

Intraoperative optical coherence tomography (iOCT) is an increasingly available imaging technique for ophthalmic microsurgery that provides high-resolution cross-sectional information of the surgical scene. We propose to build on its desirable qualities and present a method for tracking the orientation and location of a surgical needle. Thereby, we enable the direct analysis of instrument-tissue interaction directly in OCT space without complex multimodal calibration that would be required with traditional instrument tracking methods.

METHOD

The intersection of the needle with the iOCT scan is detected by a peculiar multistep ellipse fitting that takes advantage of the directionality of the modality. The geometric modeling allows us to use the ellipse parameters and provide them into a latency-aware estimator to infer the 5DOF pose during needle movement.

RESULTS

Experiments on phantom data and ex vivo porcine eyes indicate that the algorithm retains angular precision especially during lateral needle movement and provides a more robust and consistent estimation than baseline methods.

CONCLUSION

Using solely cross-sectional iOCT information, we are able to successfully and robustly estimate a 5DOF pose of the instrument in less than 5.4 ms on a CPU.

Correlative factors' analysis of postural-related ocular cyclotorsion with image-guided system

PURPOSE

To explore the correlation between ocular cyclotorsion induced by sitting and supine positions as well as other selected factors, validated by an image-guided system.

STUDY DESIGN

A cross-sectional study conducted in 73 inpatients (85 eyes) who received intraocular operations in China Medical University.

METHODS

The ocular cyclotorsion degree was recorded using an image-guided system (Verion Reference Unit, Alcon) by comparing images captured in sitting position, as well as pre- and post-different anesthesia methods in the supine position. Possible correlative factors including age, gender, eye axial length, best corrected visual acuity (BCVA), astigmatism degree, astigmatism axis, anesthesia, and comparison in laterality of eyes on ocular cyclotorsion were analyzed.

RESULTS

The total cyclotorsion rate was 88.24% and the cyclotorsion degree ranged from - 14.0° to + 12.0° with an average of 4.6° ± 3.4°. Excyclotorsion was predominant OD whereas incyclotorsion was predominant OS (p < 0.05). The effect of eye axial length, BCVA, astigmatism degree, astigmatism axis, anesthesia method, age and gender on cyclotorsion orientation was not statistically significant, neither did these factors show any significant differences in the ocular cyclotorsion degree (p > 0.05). Pre- and post-anesthesia, and different anesthetic methods, did not show any significant influence on the ocular cyclotorsion degree (p > 0.05).

CONCLUSIONS

Cyclotorsion orientation seems to be correlated only with eye laterality. None of the other investigated factors, including age, gender, eye axial length, BCVA, astigmatism degree, astigmatism axis and anesthesia seems to affect cyclotorsion orientation or degree.

Intraoperative OCT Imaging of the Argus II Retinal Prosthesis System

BACKGROUND AND OBJECTIVE

Optimal placement of the Argus II Retinal Prosthesis System (Second Sight Medical Products, Sylmar, CA) is critical. Intraoperative optical coherence tomography (OCT) allows for intrasurgical visualization and confirmation of array placement. In this study, two different OCT systems were evaluated to assess the feasibility and utility of this technology during Argus II surgery.

PATIENTS AND METHODS

Intraoperative OCT was performed on five patients undergoing Argus II implantation at Cole Eye Institute from June 2015 to July 2016. The EnVisu portable OCT (Bioptigen, Morrisville, NC) and microscope-integrated RESCAN 700 (Zeiss, Oberkochen, Germany) intraoperative OCT systems were utilized. The EnVisu was used in three patients and the RESCAN 700 in three of the five patients. Following array tacking, intraoperative OCT was performed over the entire array including the edges and tack.

RESULTS

Intraoperative OCT allowed for visualization of the array/retina interface. Microscope integration of the OCT system facilitated ease of focusing, real-time feedback, surgeon-directed OCT scanning to the areas of interest, and enhanced image quality at points of interest.

CONCLUSIONS

Intraoperative imaging of the Argus II electrode array is feasible and provides information about electrode array-retina interface and distance to help guide a surgeon. Microscope integration of OCT appears to provide an optimal and efficient approach to intraoperative OCT during Argus II array placement. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:999-1003.].

Haptic interface for robot-assisted ophthalmic surgery

Vitreo-retinal surgery is challenging, as delicate structures have to be manipulated. Eliminating tremor caused by human motions when doing micromanipulation can therefore improve the outcome of such an intervention. An eye surgery robot has been built to overcome this problem. The contribution of this paper is the design of a telemanipulation setup for the robotic system. A telemanipulation setup using a haptic device featuring force feedback as a user interface for controlling a hybrid parallel-serial micromanipulator is designed and developed. The position error control scheme is chosen and different control modes are provided. The output forces of the haptic device are analyzed. The system allows the surgeon to perform precise and comfortable micromanipulation. Nevertheless a way to provide more meaningful force feedback still has to be found.

[Understanding the Pathology and Current Treatment Strategy of Highly Myopic Complications]

The population of high myopia in Japan is large and increasing. It is a high risk factor not only for its specific macular complications but also as a precursor for cataracts and glaucoma. Myopic foveoschisis and the consequent macular hole with retinal detachment (MHRD) are caused by inner retinal traction which may include the vitreous cortex, epiretinal membrane, internal limiting membrane and posterior staphyloma formation. Vitrectomy is the 1st choice of treatment, and releasing the retina from traction is the goal. MHRD has poor anatomical success rates, and, therefore, inverted internal limiting membrane is a common treatment procedure to enhance MH closure. Myopic choroidal neovascularization occurs predominantly in highly myopic eyes, and anti-vascular endothelial growth factor therapy is the 1st line treatment. Normally the patient's eyes respond well, however, recurrence is an important issue. Conventional optical coherence tomography (OCT) and fluorescein angiography are the major diagnostic tools. At the same time, advanced technologies such as OCT-angiography and Polarization-sensitive OCT may enable an early and more accurate diagnosis. High myopia is a high risk factor for glaucoma and its mechanism is still uncertain. Studies using OCT thus far have shown variety of abnormalities occurring in highly myopic eyes inside and around the optic nerve head. High myopia has uncommon progression patterns such as preceding the papillo-macular bundle damage, especially in younger patients. Future studies are needed.

[EFFICACY OF COMBINED MICROSURGICAL TECHNIQUE IN SEVERE TRAUMATIC INJURY OF EYEBALL]

Analysis of clinical and functional results of microsurgical restoration of eyeball in remote terms after primary surgical processing for traumatic injury of eyes, using combined one-stage operative intervention on anterior and posterior segments, was presented. Satisfactory result was achieved in 56.4% injured persons, in 43.6% - functional outcome after the operation, concerning perspectives of further restoration of optic functions, have appeared unsatisfactory.

Rapid detection of bacterial endotoxins in ophthalmic viscosurgical device materials by direct analysis in real time mass spectrometry

Bacterial endotoxins are lipopolysaccharides bound to the bacterial cell wall and released when bacteria rupture or disintegrate. Possible contamination of endotoxin in ophthalmic devices can cause a painful eye inflammation or result in toxic anterior segment syndrome after cataract surgery. Measurement of bacterial endotoxin in medical device materials is difficult since endotoxin binds with polymer matrix and some of the materials are very viscous and non-water soluble, where traditional enzyme-based Limulus amebocyte lysate (LAL) assay cannot be applied. Here we propose a rapid and high throughput ambient ionization mass spectrometric (MS) method using direct analysis in real time (DART) for the evaluation of endotoxin contamination in medical device materials. Large and structurally complex endotoxin instantaneously breaks down into low-mass characteristic fragment ions using DART and is detected by MS in both positive and negative ion modes. This method enables the identification and separation of endotoxin from medical materials with a detection limit of 0.03 ng mL^-1 endotoxins in aqueous solution. Ophthalmic viscosurgical device materials including sodium hyaluronate (NaHA), non-water soluble perfluoro-n-octane (PFO) and silicone oil (SO) were spiked with different known concentrations of endotoxin and analyzed by DART MS, where the presence of endotoxin was successfully detected and featured small mass fragment ions were generated for NaHA, PFO and SO as well. Current findings showed the feasibility of measuring endotoxin contamination in medical device materials using DART-MS, which can lead to a one-step analysis of endotoxins in different matrices, avoiding any potential contamination during sample pre-treatment steps.

CRF-Based Model for Instrument Detection and Pose Estimation in Retinal Microsurgery

Detection of instrument tip in retinal microsurgery videos is extremely challenging due to rapid motion, illumination changes, the cluttered background, and the deformable shape of the instrument. For the same reason, frequent failures in tracking add the overhead of reinitialization of the tracking. In this work, a new method is proposed to localize not only the instrument center point but also its tips and orientation without the need of manual reinitialization. Our approach models the instrument as a Conditional Random Field (CRF) where each part of the instrument is detected separately. The relations between these parts are modeled to capture the translation, rotation, and the scale changes of the instrument. The tracking is done via separate detection of instrument parts and evaluation of confidence via the modeled dependence functions. In case of low confidence feedback an automatic recovery process is performed. The algorithm is evaluated on in vivo ophthalmic surgery datasets and its performance is comparable to the state-of-the-art methods with the advantage that no manual reinitialization is needed.

FBG-based sensorized light pipe for robotic intraocular illumination facilitates bimanual retinal microsurgery

In retinal surgery, microsurgical instruments such as micro forceps, scissors and picks are inserted through the eye wall via sclerotomies. A handheld intraocular light source is typically used to visualize the tools during the procedure. Retinal surgery requires precise and stable tool maneuvers as the surgical targets are micro scale, fragile and critical to function. Retinal surgeons typically control an active surgical tool with one hand and an illumination source with the other. In this paper, we present a "smart" light pipe that enables true bimanual surgery via utilization of an active, robot-assisted source of targeted illumination. The novel sensorized smart light pipe measures the contact force between the sclerotomy and its own shaft, thereby accommodating the motion of the patient's eye. Forces at the point of contact with the sclera are detected by fiber Bragg grating (FBG) sensors on the light pipe. Our calibration and validation results demonstrate reliable measurement of the contact force as well as location of the sclerotomy. Preliminary experiments have been conducted to functionally evaluate robotic intraocular illumination.

Suspensory Materials for Surgery of Blepharoptosis: A Systematic Review of Observational Studies

BACKGROUND

Frontalis suspension surgery is considered the procedure of choice in cases of blepharoptosis. Among all the materials used in this type of surgery, ophthalmic and plastic surgeons prefer to use autologous Fascia Lata. However, during years, other autogenous and exogenous materials have been introduced.

OBJECTIVES

The aim of this study was therefore that of systematically reviewing the functional results and the rate of complications of different synthetic materials, as compared to autogenous Fascia Lata. The primary objective was to determine the rates of Successful Surgeries (SSs) of these materials. The secondary objective was to assess the onset of complications. The following materials were investigated: Fascia Lata, Mersilene, polytetrafluoroethylene (PTFE) and Silicon.

DATA SOURCE AND METHODS

Following the Prisma procedure, on January 30th, 2016 we used the following electronic databases to select the studies: MEDLINE and Scopus.

RESULTS

The search strategy retrieved 48 publications that met the eligibility criteria of the systematic review. All studies were non-comparative. PTFE (n = 5) showed the best rate of SSs among the materials compared (statistically significant). Surgeries performed with autogenous Fascia Lata (n = 19) had a 87% rate of success those performed with Mersilene (n = 12)had 92% and those performed with Silicon (n = 17)88%. PTFE had the best outcome, with 99% success rate. As for complications, surgeries performed with PTFE had a higher rate of suture infections (1.9%) as compared to Fascia Lata, but lower incidence for all other complications.

CONCLUSIONS

Although most studies were good quality cohort studies, the overall quality of this evidence should be regarded as low due to their non-comparative design. Our data suggest that PTFE seems to be the most valid alternative material for frontalis suspension surgery, with low recurrence rates and good cosmetic and functional results.

Crescent-Shaped Retinal Defects Associated With Membrane Peeling With a Diamond-Dusted Membrane Scraper

Membrane peeling is a common procedure for treating diseases of the vitreoretinal interface, such as macular holes and epiretinal membranes; however, potential complications include inner retinal dimples and inner retinal optic neuropathy. The current case series describes five patients who developed large, crescentic inner retinal defects after membrane peeling with diamond-dusted membrane scrapers. The changes visualized by en face optical coherence tomography were outside the fovea and followed the expected contours of membrane scrapers being used intraoperatively. The visual acuities at the last follow-up were 20/40 or better in all five patients.

Use of Handheld Intraoperative Spectral-Domain Optical Coherence Tomography in a Variety of Vitreoretinal Diseases

BACKGROUND AND OBJECTIVE

The use of intraoperative optical coherence tomography (iOCT) has been described with a variety of imaging devices and techniques. The purpose of this investigation is to examine the role of iVue (Optovue, Fremont, CA), a commercially available, handheld spectral-domain iOCT system, in vitreoretinal surgery. PATIENTS AND METHODS For this retrospective, observational case series, patients who underwent a vitreoretinal surgical procedure and were imaged with the iVue were identified. Images were qualitatively assessed.

RESULTS

Five cases were identified, including an examination under anesthesia, epiretinal membrane, macular hole, retinal detachment, and non-clearing vitreous hemorrhage in the setting of proliferative diabetic retinopathy.

CONCLUSION

Clinically useful images were obtained in all cases, though it was difficult to center the scan on the area of interest in the retina. Further work is necessary to improve system design and investigate the ways in which iOCT can aid in vitreoretinal surgery.

Sir Harold Ridley (1906-2001): televising and filming ophthalmic surgery and eye examinations

Sir Harold Ridley is well known for his pioneering intraocular lens implantation surgery. He also had a significant commitment to the televising and filming of surgery. In his 1950 Television in Ophthalmology paper, Ridley describes the techniques he used to capture his surgery in monochrome and later in full colour for audiences at St Thomas' Hospital.

[Comparative evaluation of different corneal cross-linking techniques with respect to biomechanical stability of the cornea]

AIM

To perform a comparative analysis of the following cross-linking techniques: standard cross-linking (SCXL), local transepithelial femto cross-linking (LTF) and transepithelial intrastromal femto cross-linking with MyoRing implantation (TIF+MyoRing) in experimental animals and patients with progressive stage II--III keratoconus (KC), paying particular attention to the changes in biomechanical stability of the cornea.

MATERIAL AND METHODS

The experimental series was performed on 20 eyes of 10 rabbits. The animals were divided into 4 groups of 5. Group 1 served as the control, group 2 consisted of animals that underwent SCXL, group 3 -- of those after LTF, and group 4 -- of those after TIF+MyoRing. Femto step was performed using the IntraLase FS 60 kHz femtosecond laser, cross-linking - with the Evolution machine. The follow-up period was 1 month. Clinical study enrolled 48 patients (45 eyes) with stage II-III KC. Depending on the surgical technique all the patients were divided into 3 groups. In group I (14 eyes, 9 patients), TIF+MyoRing was performed, in group II (16 eyes, 20 patients) --SCXL, in group III (15 eyes, 19 patients) -- LTF. The follow-up period was 6 months.

RESULTS

The experiment showed a significant increase in rupture resistance of the cornea in all three groups. Six months after surgery, patients from group I demonstrated a 1.0±0.22 mmHg higher corneal resistance factor (CRF) and a 1.0±0.12 mmHg higher corneal hysteresis (CH). In group II, the said parameters increased by 0.8±0.10 mmHg and 0.6±0.16 mmHg, respectively; in group III -- by 0.8±0.25 mmHg and 0.6±0.26 mmHg, respectively. In neither group the density of endothelial cells has reduced significantly over the follow-up period. C-ONCLUSION: All three methods (LTF, TIF and SCXL) equally increase the biomechanical strength of the cornea and are safe. In patients with progressive stage II-III KC, TIF+MyoRing surgery has yielded an even higher improvement of biomechanical parameters in a 6-month follow-up period, which is due to the combination of mechanical and chemical mechanisms of corneal reinforcement.

The introduction of a new robot for assistance in ophthalmic surgery

This paper introduces the design and development of a new robotic system to assist surgeons performing ophthalmic surgeries. The robot itself is very compact and similar to an average human hand in size. Its primary application is intraocular micromanipulation in order to overcome the existing challenges in treatment of diseases like Retinal Vein Occlusion (RVO). The novel hybrid mechanism designed for this robot allows microscale motions and is stable in the presence of vibrations common in operation room (OR). The robotic system can be easily integrated into standard operation rooms and does not require modification of conventional surgical tools. This compact microsurgical system is suitable for mounting on the patient's head and thereby, solves the problem of patient motion. The compatibility of the robotic system with a real world surgical setup was evaluated and confirmed in this work.

Application of a Quality Control Circle to Reduce the Wait Times between Continuous Surgeries

PURPOSE

To investigate how to shorten patient wait times between continuous ocular operations and to evaluate the influence of a quality control circle (QCC) on operating room management.

METHODS

QCC management was established to conduct activities. Clinical data were collected to analyze the causes of long wait times between continuous surgeries. Effective measures were undertaken correspondingly.

RESULTS

The staff from QCC actively undertook measures that would significantly shorten patient wait times between continuous ocular surgeries (P < 0.05).

CONCLUSION

Multiple measures, such as setting up a QCC, enhancing the arrangement of surgical procedures, establishing effective communication channels, optimizing human resources, and integrating the use of instruments, can effectively shorten patient wait times between continuous vitreous or retinal surgeries.

Sutureless fixation of amniotic membrane for therapy of ocular surface disorders

Amniotic membrane is applied to the diseased ocular surface to stimulate wound healing and tissue repair, because it releases supportive growth factors and cytokines. These effects fade within about a week after application, necessitating repeated application. Generally, amniotic membrane is fixed with sutures to the ocular surface, but surgical intervention at the inflamed or diseased site can be detrimental. Therefore, we have developed a system for the mounting of amniotic membrane between two rings for application to a diseased ocular surface without surgical intervention (sutureless amniotic membrane transplantation). With this system, AmnioClip, amniotic membrane can be applied like a large contact lens. First prototypes were tested in an experiment on oneself for wearing comfort. The final system was tested on 7 patients in a pilot study. A possible influence of the ring system on the biological effects of amniotic membrane was analyzed by histochemistry and by analyzing the expression of vascular endothelial growth factor-A (VEGF-A), hepatocyte growth factor (HGF), fibroblast growth factor 2 (FGF 2) and pigment epithelium-derived factor (PEDF) from amniotic membranes before and after therapeutic application. The final product, AmnioClip, showed good tolerance and did not impair the biological effects of amniotic membrane. VEGF-A and PEDF mRNA was expressed in amniotic membrane after storage and mounting before transplantation, but was undetectable after a 7-day application period. Consequently, transplantation of amniotic membranes with AmnioClip provides a sutureless and hence improved therapeutic strategy for corneal surface disorders.

Human eye phantom for developing computer and robot-assisted epiretinal membrane peeling

A number of technologies are being developed to facilitate key intraoperative actions in vitreoretinal microsurgery. There is a need for cost-effective, reusable benchtop eye phantoms to enable frequent evaluation of these developments. In this study, we describe an artificial eye phantom for developing intraocular imaging and force-sensing tools. We test four candidate materials for simulating epiretinal membranes using a handheld tremor-canceling micromanipulator with force-sensing micro-forceps tip and demonstrate peeling forces comparable to those encountered in clinical practice.

First-in-human trial of a novel suprachoroidal retinal prosthesis

Retinal visual prostheses (“bionic eyes”) have the potential to restore vision to blind or profoundly vision-impaired patients. The medical bionic technology used to design, manufacture and implant such prostheses is still in its relative infancy, with various technologies and surgical approaches being evaluated. We hypothesised that a suprachoroidal implant location (between the sclera and choroid of the eye) would provide significant surgical and safety benefits for patients, allowing them to maintain preoperative residual vision as well as gaining prosthetic vision input from the device. This report details the first-in-human Phase 1 trial to investigate the use of retinal implants in the suprachoroidal space in three human subjects with end-stage retinitis pigmentosa. The success of the suprachoroidal surgical approach and its associated safety benefits, coupled with twelve-month post-operative efficacy data, holds promise for the field of vision restoration.

Trial Registration

Clinicaltrials.gov NCT01603576

Active aspiration of suprachoroidal hemorrhage using a guarded needle

BACKGROUND AND OBJECTIVE

To describe a novel technique using a guarded needle to drain suprachoroidal hemorrhage.

PATIENTS AND METHODS

A guarded needle is used to drain suprachoroidal hemorrhage under direct microscope visualization. A scleral buckling sleeve is used to create a guarded 26-gauge needle to avoid over-penetration of the needle beyond the suprachoroidal space. Active extrusion can be used to drain suprachoroidal blood.

RESULTS

The authors report two cases in which active aspiration using a guarded needle was successful in draining suprachoroidal hemorrhage without complications. In both cases, the vitreous cavity could be restored, allowing for subsequent pars plana vitrectomy.

CONCLUSION

The technique of active aspiration using a guarded needle optimizes surgeon control of suprachoroidal hemorrhage drainage and also has the added benefit of easy transition to secondary vitrectomy after drainage has been completed.

Refocusing a scanned laser projector for small and bright images: simultaneously controlling the profile of the laser beam and the boundary of the image

This paper describes a projection system for augmenting a scanned laser projector to create very small, very bright images for use in a microsurgical augmented reality system. Normal optical design approaches are insufficient because the laser beam profile differs optically from the aggregate image. We propose a novel arrangement of two lens groups working together to simultaneously adjust both the laser beam of the projector (individual pixels) and the spatial envelope containing them (the entire image) to the desired sizes. The present work models such a system using paraxial beam equations and ideal lenses to demonstrate that there is an "in-focus" range, or depth of field, defined by the intersection of the resulting beam-waist radius curve and the ideal pixel radius for a given image size. Images within this depth of field are in focus and can be adjusted to the desired size by manipulating the lenses.

Removal of a giant nonmagnetic intraocular foreign body using micro alligator forceps

PURPOSE

To introduce a new method for removal of a giant nonmagnetic intraocular foreign body using micro alligator forceps.

PATIENTS AND METHODS

Eleven patients underwent pars plana vitrectomy and lensectomy. The micro alligator forceps were used to grasp and extract the giant nonmagnetic intraocular foreign body through a sclerocorneal tunnel.

RESULTS

All patients underwent surgical removal of the intraocular foreign body successfully without any intraoperative complications. The alligator forceps were operational in the intraocular environment and effective in surgical maneuvers. There was no accidental slippage during the procedures.

CONCLUSION

Micro alligator forceps are a feasible option for removal of giant nonmagnetic intraocular foreign body during vitreoretinal surgery and offer advances in terms of operating stability and surgical safety.

Design and development of miniature parallel robot for eye surgery

A five degree-of-freedom (DOF) miniature parallel robot has been developed to precisely and safely remove the thin internal limiting membrane in the eye ground during vitreoretinal surgery. A simulator has been developed to determine the design parameters of this robot. The developed robot's size is 85 mm × 100 mm × 240 mm, and its weight is 770 g. This robot incorporates an emergency instrument retraction function to quickly remove the instrument from the eye in case of sudden intraoperative complications such as bleeding. Experiments were conducted to evaluate the robot's performance in the master-slave configuration, and the results demonstrated that it had a tracing accuracy of 40.0 μm.

Detachable microsphere scalpel tips for potential use in ophthalmic surgery with the erbium:YAG laser

Vitreoretinal surgery is performed using mechanical dissection that sometimes results in iatrogenic complications, including vitreous hemorrhage, retinal breaks, incomplete membrane delamination, retinal distortion, microscopic damage, etc. An ultraprecise laser probe would be an ideal tool for cutting away pathologic membranes; however, the depth of surgery should be precisely controlled to protect the sensitive underlying retina. The ultraprecise surgical microprobe formed by chains of dielectric spheres for use with the erbium:YAG laser source (λ=2940  nm), with extremely short optical penetration depth in tissue, was optimized. Numerical modeling demonstrated a potential advantage of five-sphere focusing chains of sapphire spheres with index n=1.71 for ablating the tissue with self-limited depth around 10 to 20 μm. Novel detachable microsphere scalpel tips formed by chains of 300 μm sapphire (or ruby) spheres were tested on ophthalmic tissues, ex vivo. Detachable scalpel tips could allow for reusability of expensive mid-infrared trunk fibers between procedures, and offer more surgical customization by interchanging various scalpel tip configurations. An innovative method for aiming beam integration into the microsphere scalpel to improve the illumination of the surgical site was also shown. Single Er:YAG pulses of 0.2 mJ and 75-μs duration produced ablation craters in cornea epithelium for one, three, and five sphere structures with the latter generating the smallest crater depth (10 μm) with the least amount of thermal damage depth (30 μm). Detachable microsphere laser scalpel tips may allow surgeons better precision and safety compared to mechanical scalpels when operating on delicate or sensitive areas like the retina.

A survey of healthcare industry representatives' participation in surgery: some new ethical concerns

OBJECTIVE

To provide preliminary evidence of the types and amount of involvement by healthcare industry representatives (HCIRs) in surgery, as well as the ethical concerns of those representatives.

METHODS

A link to an anonymous, web-based survey was posted on several medical device boards of the website http://www. cafepharma.com. Additionally, members of two different medical device groups on LinkedIn were asked to participate. Respondents were self-identified HCIRs in the fields of orthopedics, cardiology, endoscopic devices, lasers, general surgery, ophthalmic surgery, oral surgery, anesthesia products, and urologic surgery.

RESULTS

A total of 43 HCIRs replied to the survey over a period of one year: 35 men and eight women. Respondents reported attending an average of 184 surgeries in the prior year and had an average of 17 years as an HCIR and six years with their current employer. Of the respondents, 21 percent (nine of 43) had direct physical contact with a surgical team or patient during a surgery, and 88 percent (38 of 43) provided verbal instruction to a surgical team during a surgery. Additionally, 37 percent (16 of 43) had participated in a surgery in which they felt that their involvement was excessive, and 40 percent (17 of 43) had attended a surgery in which they questioned the competence of the surgeon.

CONCLUSIONS

HCIRs play a significant role in surgery. Involvement that exceeds their defined role, however, can raise serious ethical and legal questions for surgeons and surgical teams. Surgical teams may at times be substituting the knowledge of the HCIR for their own competence with a medical device or instrument. In some cases, contact with the surgical team or patient may violate the guidelines not only of hospitals and medical device companies, but the law as well. Further study is required to determine if the patients involved have any knowledge or understanding of the role that an HCIR played in their surgery.

Use of silicone tubes to repair canalicular lacerations via a novel method

PURPOSE

To develop a novel method to repair canalicular lacerations using silicone tubes.

METHODS

A total of 47 adult patients (47 eyes) with canalicular lacerations were collected from the outpatient department from November 2010 to December 2012. The age ranged from 16 to 53 years. Among the 47 eyes, 37 had lower canalicular lacerations, 6 had upper canalicular lacerations, and 4 had bicanalicular lacerations. A soft probe was made using a stainless steel acupuncture needle, which was inserted into the lumen of the proximal part of the catheter to increase its rigidity. The probe was then inserted into the lacrimal sac and nasolacrimal duct. After retrieval of the catheters, the two ends of the silicone tube were securely tied (end to end) to the catheters. The silicon tube outside the nostril formed a U-shape. The catheters were then pulled upward until the silicone tube was completely located in the canalicular system. The catheters were cut off of the silicone tube near the site of the connection. The two ends of the silicone tube were cut short, -2mm out of the lacrimal punctum, and tied securely, end to end. The length of the tube between the upper and lower punctum was adjusted to ensure that no tension was present in the medial cathus, and the suture was removed through the nostril. The silicone tube was removed 3-10 months after this novel canalicular intubation procedure (NCI).

RESULTS

All cases were anatomically rehabilitated after surgery. The silicone tube was removed after implanted in 3-10 months (mean 4.5 +/- 1.3 months), the average follow-up time was 11.8 months after removal. In total, 45 eyes in all 47 eyes (95.74%) were free from obstruction. Among them, 41 eyes (91.11%) achieved complete success (completely disappearance of epiphora after tube removal), 4 eyes (8.89%) achieved partial success (irritation occurs under stimulation conditions, such as wind or cold conditions), 4 eyes showed postoperative tearing, with three eyes having inferior lacrimal duct laceration, and one eye with superior canalicular laceration. Apart from two cases (4.26%) suffering inferior punctum splitting, no other associated issues occurred with the silicone tube or iatrogenic injury and lacrimal complications.

CONCLUSION

For adult patients with canalicular laceration, the NCI was an effective, atraumatic surgery, which has fewer complications than traditional canalicular suture.

Management of neurosurgical instruments and patients exposed to Creutzfeldt-Jakob disease

OBJECTIVE

To summarize the approaches used to manage exposure of patients to inadequately sterilized neurosurgical instruments contaminated as a result of Creutzfeldt-Jakob disease (CJD).

METHODS

Information on past CJD exposure incidents reported to the Centers for Disease Control and Prevention (CDC) was aggregated and summarized. In addition, inactivation studies were reviewed, and data from selected publications were provided for reference.

RESULTS

Nineteen incidents of patient exposure to potentially CJD-contaminated instruments were reported to the CDC, including 17 that involved intracranial procedures and 2 that involved ophthalmologic procedures. In more than 50% of incidents, the neurosurgical procedures were performed for diagnostic work up of the index patients. At least 12 of the hospitals had multiple neurosurgical sets, and the CJD-contaminated instruments could not be identified in 11 of 19 hospitals. In 12 of 15 hospitals with neurosurgical incidents, a decision was made to notify patients of their potential exposure.

CONCLUSIONS

Neurosurgical instruments used for treatment of patients with suspected or diagnosed CJD or patients whose diagnosis is unclear should be promptly identified and sterilized using recommended CJD decontamination protocols. Inability to trace instruments complicates appropriate management of exposure incidents. The feasibility of instituting instrument tracking procedures should be considered.

Medical devices; ophthalmic devices; classification of the scleral plug. Final rule

The Food and Drug Administration (FDA or Agency) is classifying the scleral plug into class II (special controls), and exempting the scleral plugs composed of surgical grade stainless steel (with or without coating in gold, silver, or titanium) from premarket notification (510(k)) and continuing to require premarket notification (510(k)) for all other scleral plugs in order to provide a reasonable assurance of safety and effectiveness of the device. The scleral plug is a prescription device used to provide temporary closure of a scleral incision during an ophthalmic surgical procedure.

Performance of a 6-degree-of-freedom active microsurgical manipulator in handheld tasks

This paper presents the first experimental results from human users of a new 6-degree-of-freedom handheld micromanipulator. This is the latest prototype of a fully-handheld system, known as "Micron," which performs active compensation of hand tremor for microsurgery. The manipulator is a miniature Gough-Stewart platform incorporating linear ultrasonic motors that provide a cylindrical workspace 4 mm long and 4 mm wide. In addition, the platform allows the possibility of imposing a remote center of motion for controlling motion not only at the tip but also at the entry point in the sclera of the eye. We demonstrate hand tremor reduction in both static and dynamic micromanipulation tasks on a rubber pad. The handheld performance is also evaluated in an artificial eye model while imposing a remote center of motion. In all cases, hand tremor is significantly reduced.

Cytotoxicity of cannulas for ophthalmic surgery after cleaning and sterilization: evaluation of the use of enzymatic detergent to remove residual ophthalmic viscosurgical device material

PURPOSE

To evaluate the cytotoxicity of reusable cannulas for ophthalmic surgery after the cannulas were filled with an ophthalmic viscosurgical device (OVD) and cleaned with an enzymatic detergent.

SETTING

Microbiological Testing Laboratory, Department of Medical-Surgical Nursing, University of São Paulo School of Nursing, and Cell Culture Section, Adolfo Lutz Institute, São Paulo, Brazil.

DESIGN

Experimental study.

METHODS

The sample consisted of 30 reusable 25-gauge injection cannulas, 20.0 mm in length, whose lumens were filled with an OVD solution for 50 minutes. The following steps were used to process the cannulas: (1) presoaking, (2) washing the lumen using a high-pressure water jet, (3) backwashing with enzymatic detergent in ultrasonic cleaner, (4) preliminary rinsing with tap water, (5) final rinsing with sterile distilled water, (6) drying with compressed filtered air, (7) wrapping in surgical-grade paper, and (8) steam sterilization at 134°C for 4 minutes. The cannulas were then tested for cytotoxicity according to the United States Pharmacopeia 32.

RESULTS

The cleaning protocol used in this study removed residues of OVD solution and enzymatic detergent as shown by the lack of cytotoxicity of all sample extracts.

CONCLUSION

This cleaning protocol has the potential to minimize the occurrence of toxic anterior segment syndrome associated with residues of OVD solutions and enzymatic detergents.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Unified detection and tracking of instruments during retinal microsurgery

Methods for tracking an object have generally fallen into two groups: tracking by detection and tracking through local optimization. The advantage of detection-based tracking is its ability to deal with target appearance and disappearance, but it does not naturally take advantage of target motion continuity during detection. The advantage of local optimization is efficiency and accuracy, but it requires additional algorithms to initialize tracking when the target is lost. To bridge these two approaches, we propose a framework for unified detection and tracking as a time-series Bayesian estimation problem. The basis of our approach is to treat both detection and tracking as a sequential entropy minimization problem, where the goal is to determine the parameters describing a target in each frame. To do this we integrate the Active Testing (AT) paradigm with Bayesian filtering, and this results in a framework capable of both detecting and tracking robustly in situations where the target object enters and leaves the field of view regularly. We demonstrate our approach on a retinal tool tracking problem and show through extensive experiments that our method provides an efficient and robust tracking solution.

[Understanding the advantages and disadvantages of femtosecond laser comprehensive applications in ophthalmology]

The femtosecond (FS) laser is a novel laser technology, and is approved clinical application by FDA in 2000. FS laser initially mainly used in corneal refractive surgery to replace the mechanical microkeratome. Since the accuracy and controllability of the FS laser is very high, it shows superiority in the field of corneal refractive surgery. And with the development of the relative hard and software, FS laser is began to used in other fields of ophthalmology, such as corneal transplants, cataract surgery, as well as assisted diagnosis et al., although still have some limitations, the preliminary clinical results have been shown a very good prospects in the ophthalmology fields. Therefore, we reviewed the alternative applications, challenges and limitations, research direction in the future of FS laser, so that provide a reference and revelations for the peers.