Soft Tissue Robotic Assisted Orbital Surgery Using da Vinci SP: A Cadaveric Experience.

PURPOSE: Robotic surgical techniques have transformed many surgical specialties however robotic techniques and applications have been much more limited in ophthalmology. This study aims to evaluate the feasibility of robotic assisted orbital surgery using a single-port novel robotic platform, the da Vinci SP. METHODS: A series of orbital procedures were performed in cadaveric specimens utilizing the da Vinci SP robotic system. The procedures performed included lacrimal gland dissection and biopsy, medial and lateral orbital wall dissections, enucleation, and lid-sparing orbital exenteration. Successful completion of each procedure was defined by the operating surgeon and was considered the primary outcome and marker of feasibility. RESULTS: Seven cadaveric procedures were performed in 3 cadaveric specimens. All 7 procedures were completed successfully without complication. Setup optimization occurred throughout the study and setup and operative times were acceptable. Three instrument arms and 1 endoscope were utilized throughout the study allowing 3 arm operating and dynamic retraction. Instrument size was found to limit surgical access and precision particular at the orbital apex. CONCLUSIONS: This preclinical study demonstrates that the da Vinci SP can be utilized within the orbit and is feasible for several applications. Robotic surgical systems offer significant advantages over conventional techniques and should be embraced. However, current commercially available robotic platforms are not optimized for the orbit and have their limitations although they may be suitable for some clinical applications.

Comparison of the effects of operating microscopes with light emitting diode and halogen light source on the eye: a rabbit study.

PURPOSE: To evaluate the potential toxicity of operation microscopes with halogen and light emitting diode (LED) light source on the rabbit eyes. MATERIALS AND METHODS: Thirty-two eyes of 16 male New Zealand pigmented rabbits were involved in the study. The rabbits were divided into two groups according to the type of light source applied. Only one eye of each rabbit was exposed to illumination light, unexposed fellow eyes served as the control group. Experimental groups included group 1 exposed to halogen light for 2 h and evaluated 1 day and 1 week after the illumination, group 2 exposed to LED light for two hours and evaluated 1 day and 1 week after the illumination. On the first and seventh days after exposing the light, we evaluated the rabbit corneas using in vivo confocal microscopy (IVCM). At the end of the seventh day, the Hematoxylin-eosin staining and TUNEL staining were performed to investigate the presence of apoptosis in the retina and retina pigment epithelium. RESULTS: Early IVCM findings revealed corneal epithelial cell ovalization and indistinct intercellular borders in the halogen light group. We also observed more increase in the keratocyte density index (23.7% vs 14.1%, p = 0.001, respectively) and the Bowman reflectivity index (12.4% vs 4.1%, p = 0.001, respectively) at first day of the light exposure in halogen light group compared to LED light group. However, late IVCM indicated that these findings disappeared one week later. No apoptosis was observed in the corneal and retinal layers in early and late examination groups. CONCLUSION: The present experimental study demonstrated that both halogen and LED lights, which were commonly used for microscopic eye surgery, had no sustained adverse effect on the cornea and retina of the rabbits; however, halogen light had a temporary adverse effect on corneal epithelium and stroma, which resolved within 1 week.

Regional Anesthesia for Pediatric Ophthalmic Surgery: A Review of the Literature.

Ophthalmic pediatric regional anesthesia has been widely described, but infrequently used. This review summarizes the available evidence supporting the use of conduction anesthesia in pediatric ophthalmic surgery. Key anatomic differences in axial length, intraocular pressure, and available orbital space between young children and adults impact conduct of ophthalmic regional anesthesia. The eye is near adult size at birth and completes its growth rapidly while the orbit does not. This results in significantly diminished extraocular orbital volumes for local anesthetic deposition. Needle-based blocks are categorized by relation of the needle to the extraocular muscle cone (ie, intraconal or extraconal) and in the cannula-based block, by description of the potential space deep to the Tenon capsule. In children, blocks are placed after induction of anesthesia by a pediatric anesthesiologist or ophthalmologist, via anatomic landmarks or under ultrasonography. Ocular conduction anesthesia confers several advantages for eye surgery including analgesia, akinesia, ablation of the oculocardiac reflex, and reduction of postoperative nausea and vomiting. Short (16 mm), blunt-tip needles are preferred because of altered globe-to-orbit ratios in children. Soft-tip cannulae of varying length have been demonstrated as safe in sub-Tenon blockade. Ultrasound technology facilitates direct, real-time visualization of needle position and local anesthetic spread and reduces inadvertent intraconal needle placement. The developing eye is vulnerable to thermal and mechanical insults, so ocular-rated transducers are mandated. The adjuvant hyaluronidase improves ocular akinesia, decreases local anesthetic dosage requirements, and improves initial block success; meanwhile, dexmedetomidine increases local anesthetic potency and prolongs duration of analgesia without an increase in adverse events. Intraconal blockade is a relative contraindication in neonates and infants, retinoblastoma surgery, and in the presence of posterior staphylomas and buphthalmos. Specific considerations include pertinent pediatric ophthalmologic topics, block placement in the syndromic child, and potential adverse effects associated with each technique. Recommendations based on our experience at a busy academic ophthalmologic tertiary referral center are provided.

New retinal tack designs: an analysis of retention forces in human scleral tissue.

PURPOSE: The study aimed to construct a new retinal tack design with high retention forces to prevent spontaneous disentanglement in cases of complicated retinal surgery. METHODS: Six new forms for the peak of a retinal tack were developed using computer-aided design (CAD); then a prototype was produced for each model. Finally, standardised design testing was conducted using human (ex vivo) sclera by logging 15 consecutive measurements for each model. RESULTS: Seven different models underwent pull-out testing (six new models and the original tack model), but two tack models (Model 4, Model 5) failed to penetrate the human tissue. The highest pull-out forces (median) were measured for Model 3, followed by Model 6, Model 2 and Model 1. The original Heimann tack (Model H) was found to have the lowest retention forces. CONCLUSION: The different tack designs altered the penetration and holding forces. The retention forces of the proposed peak design led to a significant increase in the retention forces that were more than twice as high as those in the original Heimann Model.

Microscopic Ophthalmic Surgery Using a Freely Movable Arm Support Robot: Basic Experiment and Clinical Experience.

INTRODUCTION: The disadvantage of conventional armrests is the difficulty to adjust their height and position during surgery. OBJECTIVES: We investigated whether a freely movable armrest (FMA) that follows the surgeon's arm is useful for reducing surgeon fatigue and arm tremors and for improving surgical accuracy. METHODS: In the basic study, a corneal suture was placed in porcine eyes with FMA (FMA group) or without FMA (non-FMA group). The suture was intended to pass through two points. Tremor was quantified using motion-tracking software when the needle was held. Subjective symptoms of arm-related fatigue were scored using a questionnaire. Suturing accuracy was compared between the groups. In the clinical study, the same surgeon performed corneal transplantation, cataract surgery, and glaucoma surgery with or without FMA. Fatigue scores from the questionnaire were then compared. RESULTS: In the basic study, hand tremor at rest was significantly improved with FMA (p < 0.0001). The subjective arm fatigue score was significantly reduced (p = 0.0465), while the subjective tremor score was also significantly improved (p = 0.0453). There were no differences in the accuracy of corneal suturing with or without FMA. In the clinical study, the total and arm-related fatigue scores during corneal transplantation and glaucoma surgery tended to improve. CONCLUSIONS: FMA is a useful tool for fixing the surgeon's arm in any position and may improve the quality of ophthalmic surgery by reducing hand tremor and fatigue.

Semi-permanent transcorneal filter support and in vivo surgical implantation technique for open-angle glaucoma treatment.

Primary open-angle glaucoma is a progressive disease affecting nearly 60 million people worldwide which, if left untreated, can lead to optic nerve head damage and complete loss of sight. Current interventions include: pharmaceutical drops, laser surgery, shunts, and bleb; however, these methods provide insufficient long-term efficacy in intraocular pressure management. We developed a semi-permanent, implantable transcorneal duct as a new aid in the treatment of this disease. The duct, composed of an intracorneal stabilizing washer and hollow screw, creates an interface between the anterior chamber and the external environment, allowing for the outflow of excess aqueous humor. We discuss the fluid mechanics behind designing and implementing a filter material capable of preventing the ingress of bacteria and viruses while modifying aqueous humor outflow resistances to pre-glaucomatous levels, finding the effective radius of such a material to be 10.44 µm. After performing surgical implantation in four rabbit eyes, subsequent testing showed successful integration between the screw and washer. Colored saline injections highlighted fluid flow progression out of the eye through the duct, suggesting that the device may be a viable approach to treating high intraocular pressure created by open-angle glaucoma.

Rheological and Adhesive Properties to Identify Cohesive and Dispersive Ophthalmic Viscosurgical Devices.

The purpose of this study is to evaluate the usefulness of the rheological properties and adhesive force of ophthalmic viscosurgical devices (OVDs) as parameters for understanding and identifying the surgical behavior of cohesive and dispersive OVDs. The apparent viscosity, and the storage and loss moduli (dynamic rheological parameters) of 50% chondroitin sulfate (CS), 3% sodium hyaluronate (HA), Shellgan (the combination of 3% HA and 4% CS), Opegan (1% HA with a low molecular mass) and Opegan-Hi (1% HA with a high molecular mass) were obtained with a rheometer. The adhesive force of each sample was measured by using a texture analyzer. Opegan-Hi showed a solid-like behavior, while 50% CS showed a fluid-like behavior from their apparent viscosity and dynamic rheological parameters. Shellgan, 3% HA, and Opegan exhibited similar rheological properties and intermediate characteristics between Opegan-Hi and 50% CS, although their respective values were slightly different. Among these OVD samples, the adhesive force was higher in the order of 50% CS > Shellgan, 3% HA > Opegan > Opegan-Hi. The adhesive force of dispersive OVDs tended to be higher than that of cohesive OVDs, which correlated well with the removal times of OVDs from the eye that have previously been reported. In conclusion, we demonstrated that cohesive OVDs and dispersive OVDs have particular rheological and adhesive properties that can be applied to identify both types. These parameters obtained in this study provide useful information for a greater understanding and prediction of the behavior of OVDs in the eye during surgery.

Blunt Scissors Stromal Dissection Technique Compared With Big-Bubble Deep Anterior Lamellar Keratoplasty.

OBJECTIVES: To evaluate the clinical findings and results of new modified manual deep anterior lamellar keratoplasty (M-DALK) technique compared with a big-bubble DALK (BB-DALK) technique in eyes with corneal scars or lesions. METHODS: A prospective, nonrandomized, comparative study included 65 eyes of 65 patients treated by M-DALK using the blunt scissors lamellar dissection technique or standard BB-DALK. Visual acuity, endothelial cell density, corneal cylinder (Cyl), central corneal thickness (CCT), residual stromal thickness and aberrometric values were recorded pre-treatment and 1, 3, 6, 12 and 18 months after treatment. RESULTS: Thirty-five eyes of 35 patients underwent deep anterior lamellar keratoplasty (DALK) with successful big-bubble technique, whereas 30 eyes of 30 patients underwent DALK with manual technique (in 10 eyes as a primary technique, in 20 eyes as a secondary technique). Successful big-bubble formation was achieved in 35 of 55 (64%) eyes. Microperforations occurred in three eyes in BB-DALK group, in six eyes in M-DALK group, and DALK could be completed successfully in these eyes. Visual acuity and endothelial cell loss results were not significantly different between groups during follow-up period. Mean CCT was significantly different between groups (P=0.035). Mean corneal Cyl, residual stromal thickness, and aberrometric values were similar between groups (P>0.05) at the final visit. CONCLUSION: New modified M-DALK technique has similar clinical findings and results with BB-DALK when using as a primary or secondary approach.

Evaluation of Ophthalmic Surgical Instrument Sterility Using Short-Cycle Sterilization for Sequential Same-Day Use.

PURPOSE: The common practice of short-cycle sterilization for ophthalmic surgical instrumentation has come under increased regulatory scrutiny. This study was undertaken to evaluate the efficacy of short-cycle sterilization processing for consecutive same-day cataract procedures. DESIGN: Testing of specific sterilization processing methods by an independent medical device validation testing laboratory. PARTICIPANTS: Phaco handpieces from 3 separate manufacturers were tested along with appropriate biologic indicators and controls using 2 common steam sterilizers. METHODS: A STATIM 2000 sterilizer (SciCan, Canonsburg, PA) with the STATIM metal cassette, and an AMSCO Century V116 pre-vacuum sterilizer (STERIS, Mentor, OH) using a Case Medical SteriTite container (Case Medical, South Hackensack, NJ) rigid container were tested using phaco tips and handpieces from 3 different manufacturers. Biological indicators were inoculated with highly resistant Geobacillus stearothermophilus, and each sterility verification test was performed in triplicate. Both wrapped and contained loads were tested with full dry cycles and a 7-day storage time to simulate prolonged storage. In adherence with the manufacturers' instructions for use (IFU), short cycles (3.0-3.5-minute exposure times) for unwrapped and contained loads were also tested after only 1 minute of dry time to simulate use on a consecutive case. Additional studies were performed to demonstrate whether any moisture present in the load containing phaco handpieces postprocessing was sterile and would affect the sterility of the contents after a 3-minute transit/storage time. This approximated the upper limit of time needed to transfer a containment device to the operating room. MAIN OUTCOME MEASURES: Presence or absence of microbial growth from cultured test samples. RESULTS: All inoculated test samples from both sterilizers were negative for growth of the target organism whether the full dry phase was interrupted or not. Pipetted postprocessing moisture samples and swabs of the handpieces were also negative for growth after a 3-minute transit/storage time. CONCLUSIONS: These studies support the use of unwrapped, short-cycle sterilization that adheres to the IFU of these 2 popular Food and Drug Administration-cleared sterilizers for sequential same-day cataract surgeries. A full drying phase is not necessary when the instruments are kept within the covered sterilizer containment device for prompt use on a sequential case.

Robotic-assisted surgery in ophthalmology.

PURPOSE OF REVIEW: Provide an overview of the current landscape of robotics in ophthalmology, including the pros and cons of system designs, the clinical development path, and the likely future direction of the field. RECENT FINDINGS: Robots designed for eye surgery should meet certain basic requirements. Three designs are currently being developed: smart surgical tools such as the steady hand, comanipulation devices and telemanipulators using either a fixed or virtual remote center of motion. Successful human intraocular surgery is being performed using the Preceyes surgical system. Another telemanipulation robot, the da Vinci Surgical System, has been used to perform a pterygium repair in humans and was successful in ex-vivo corneal surgery despite its nonophthalmic design. Apart from Preceyes' BV research platform, none of the currently eye-specific systems has reached a commercial stage. Systems are likely to evolve from robotic assistance during specific procedural steps to semiautonomous surgery, as smart sensors are introduced to enhance the basic functionalities of robotic systems. SUMMARY: Robotics is still in its infancy in ophthalmology but is rapidly reaching a stage wherein it will be introduced into everyday ophthalmic practice. It will most likely be introduced first for demanding vitreo-retinal procedures, followed by anterior segment applications.

Comparison of the MyoRing implantation depth by mechanical dissection using PocketMaker microkeratome versus Melles hook via AS-OCT.

BACKGROUND: This paper seeks to evaluate the depth and outcomes of MyoRing implantation using two mechanical dissection procedures including: PocketMaker microkeratome in opposition to the Melles hook method. METHODS: This retrospective study was carried out on 39 eyes of 38 keratoconus patients (28 male and 10 female) with the mean age of [Formula: see text] years and had undergone MyoRing implantation by the two mentioned methods. The MyoRing was inserted into the corneal pocket which was made manually in 18 eyes (Melles hook group) or with PocketMaker microkeratome in 21 eyes (PocketMaker group). The mean follow up time was [Formula: see text] months with pre-operative and post-operative ophthalmic examination including uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), keratometry readings and central corneal thickness measurement. AS-OCT (Casia, SS-1000, Tomey, Nagoya, Japan) imaging was used to measure MyoRing insertion depth, exactly. RESULTS: Pre-operative and post-operative UCVA (LogMAR) mean change for the PocketMaker and Melles hook groups were recorded at 0.75 ± 0.32 and 0.78 ± 0.33, respectively. Similarly, BCVA (LogMAR) mean change were 0.27 ± 0.22 and 0.23 ± 0.22. Mean keratometry (Kmean) change were 6.06 ± 4.18 and 6.56 ± 3.55 respectively. UCVA change (P = 0.767), BCVA change (P = 0.77) and Kmean change (P = 0.693) showed that there was no statistically significant difference between both groups for any parameter. Depth measurements achieved from AS-OCT images showed that there was no statistically significant difference in pocket depth between two methods of MyoRing implantation (P = 0.413). CONCLUSIONS: The results of Myoring implantation outcomes using mechanical dissection via PocketMaker microkeratome as against Melles hook are comparable.

Punctal Ectropion repair using the Raus-Garito clamp.

PURPOSE: To evaluate the results from the correction of ectropion of the punctum lacrimale in lower eyelids with a new surgical clamp. DESIGN: Prospective study. METHODS: Eighty eight eyelids in 55 patients with mild and moderate ectropion were included in the study. An excision of a diamond of tarso-conjunctiva with retractor reattachment and concomitant correction of horizontal lid laxity, if present, was performed. RESULTS: Resolution of tearing was obtained in 77 eyes. In 11 eyes, persistent tearing was reported. CONCLUSION: Conclusion:Conclusion: Repair of early to intermediate ectropion of the lacrimal punctum using the Raus-Garito clamp is associated with a good functional and cosmetic outcome.

Utilising the Alexis Retractor for lateral orbital access, a case series.

Lateral orbital surgery is challenging and typically involves the use of multiple traction sutures and retractors. This case series describes a novel technique utilising the Alexis retractor to provide access for lateral orbital surgery. Thirteen cases were included and the surgical technique has been described and illustrated. There were no post-operative infections or complications and the Alexis retractor provided excellent exposure whilst reducing the need for further surgical retractors.

George Critchett (1817-1882) and His Son George Anderson Critchett (1845-1925).

George Critchett (1817-1882) and his son George Anderson Critchett (1845-1925) have influenced the development of ophthalmology and ocular surgery for about a century. They presented new ocular operations such as Critchett's advancement operation, Critchett's corneal staphyloma operation, and Critchett's keratoconus operation, and they invented new surgical instruments such as Critchett's cataract knife, Critchett's scissors, and Critchett's fixation forceps. Both were delicate ocular surgeons managing complex and difficult surgeries.

[Flexible Guidance of Ultra-Short Laser Pulses in Ophthalmic Therapy Systems]. / Flexible Führung ultrakurzer Laserpulse in ophthalmologischen Therapiesystemen.

In the last 20 years, the role of ultrashort pulsed lasers in ophthalmology has become increasingly important. However, it is still impossible to guide ultra-short laser pulses with standard glass fibres. The highly energetic femtosecond pulses would destroy the fibre material, and non-linear dispersion effects would significantly change beam parameters. In contrast, photonic crystal fibres mainly guide the laser pulses in air, so that absorption and dispersive pulse broadening have essentially no effect. This article compares classical beam guidance with mirrors, lenses and prisms with photonic crystal fibres and describes the underlying concepts and the current state of technology. A classical mirror arm possesses more variable optical properties, while the HCF (Hollow-Core Photonic Crystal Fibre) must be matched in terms of the laser energy and the laser spectrum. In contrast, the HCF has more advantages in respect of handling, system integration and costs. For applications based on photodisruptive laser-tissue interaction, the relatively low damage threshold of photonic crystal fibres compared to classic beam guiding systems is unacceptable. If, however, pulsed laser radiation has a sufficiently low peak intensity, e.g. as used for plasma-induced ablation, photonic crystal fibres can definitely be considered as an alternative solution to classic beam guidance.

[Keratoprosthesis with Biological Haptic - The Düsseldorf-Offenburg-Experience with Osteo-Odonto- and Tibia-Keratoprosthesis]. / Zum Stand der Keratoprothesen mit biologischer Haptik ­ Die Düsseldorf-Offenburger-Erfahrungen mit Osteo-Odonto- und Tibia-Keratoprothese.

In severe ocular surface disease with limbal stem cell deficiency associated with severe dry eye, penetrating keratoplasty is likely to fail. In these cases, and provided the posterior segment is normal, keratoprosthesis surgery (KPro) can achieve visual rehabilitation. In KPros with an autologous biological haptic, a bone-tooth-complex (osteo-odonto-keratoprothesis, OOKPro) or a piece of tibial cortex (tibia-keratoprosthesis, TKPro) is used to carry a PMMA cylinder. This construct can successfully be implanted even in severely dry eyes and in those with autoimmune disease, in which other KPro designs frequently fail. Herein we review the published anatomic long-term results of OOKPro and TKPro on our own patients. With a mean follow-up of 7.5 years (max. 20.6) for OOKPro and 4.5 years (max. 13.3) for TKPro patients, the retention rate was 91 and 86%, respectively. We are unaware of any other technique for artificial replacement of the cornea with equally positive long-term results as KPros with a biological haptic.

[Mid- and Longterm Experiences with the Boston-Keratoprosthesis. The Cologne and Salzburg Perspective]. / Mittel- und langfristige Erfahrungen mit der Boston-Keratoprothese. Die Kölner und Salzburger Perspektive.

Background Eyes with severe corneal opacifications and insufficient prognosis for high-risk corneal transplantation can be considered for the implantation of a Boston-keratoprosthesis. Since 2013, this technique of "artificial" corneal replacement is provided to high-risk eyes at the Department of Ophthalmology, University of Cologne and for 9 years at the University of Salzburg. In the meantime, a type I Boston keratoprosthesis (BI-KPro) has been implanted in 24 eyes in Cologne and in 28 eyes in Salzburg. Methods In this article, results and complications according to BI-KPro are discussed, both from the literature in PubMed, as well as from our own experiences. Results Twenty-four eyes of 22 patients had been provided with a BI-KPro since September 2013, of which only one keratoprosthesis could not be obtained thus far, and an increase in visual acuity could be achieved in 23 eyes (96%). On average, 1.5 revisions per eye were required during the postoperative course. Since 2007, a BI-KPro has been implanted in 28 eyes in Salzburg. In 62% (16 of 26 eyes), visual acuity increased postoperatively, with a complication rate of 81% in a longer follow-up period. In both cohorts, the spectrum of complications ranged from retroprosthetic membrane formation, to secondary glaucoma, to infectious keratitis with or without graft melting, to vitritis, to endophthalmitis. Conclusion The range of possible complications according to BI-KPro is broad, but the BI-KPro represents currently the most widely used form of artificial corneal replacement in high-risk eyes and leads to visual improvement in most patients.

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.