Silicone Oil Research Articles

Silicone on the Move: Migratory Siliconoma After Retinal Surgery Report of a Case and Review of the Literature.

Silicone granulomas, or "siliconomas," are the common foreign-body inflammatory responses to injected silicone material. In rare cases, siliconomas develop remotely from the original site of injection, secondary to silicone migration. If a history of silicone injection is not noted, such lesions risk misdiagnosis (possibly as infection or malignancy). Intraocular silicone oil is commonly used in retinal detachment surgery, with occasional reports of granulomatous responses after its application in this context. Here, we report a 66-year-old man who developed a periocular silicone granuloma years after scleral buckle surgery for a detached retina and summarize the literature of similar reports of migratory siliconoma.

Theoretical and experimental study of a two-dimensional circular stealth acoustic lens

The detection of underwater acoustic signals is a key focus in ocean development, and acoustic metamaterials play a crucial role in achieving this goal. Pentamode metamaterials exhibit fluid-like properties, allowing for the propagation of compressional waves without shear waves. In this study, a two-dimensional circular stealth acoustic lens based on pentamode metamaterials was proposed. By applying the transformation acoustics theory, the theoretical properties of circular stealth acoustic lenses were calculated, and they were verified with Finite Element Method (FEM). A practical model was designed with pentamode metamaterials and silicone oil, and its performance was verified with FEM software. A half-model was fabricated, and underwater experiments demonstrate that it does not effectively affect the propagation state of acoustic waves. The consistency between theoretical results and experimental findings highlights practical significance and broad application prospects for the circular stealth acoustic lens in the field of acoustic detection.

A novel drip-irrigative technique for enhanced epiretinal perfluorocarbon liquid clearance during vitreoretinal surgery

PurposeTo present a novel intraoperative application technique of basic salt solution (BSS) perfusate to address residual epiretinal perfluorocarbon liquid (PFCL) droplets.MethodsFollowing standard liquid-gas exchange and aspiration of visible PFCL using a flute needle, the adjuvant drip-irrigative method is employed. A 2mL needle containing BSS is introduced and maneuvered circumferentially around the posterior pole while injecting BSS intermittently to obviate droplet presence. Subsequently, droplets lying flat to the surface drain via the flute needle, and the process if repeated until no droplets are visible.ResultsAmong 112 consecutive patients diagnosed with rhegmatogenous retinal detachment (RDD) with at least 3 months follow-up, 109 patients (109 eyes, [97%]) experienced no PFCL-related complications follow pars plana vitrectomy. Among three patients with PFCL-related complications, two (2 eyes) presented with residual droplets on the retinal surface during silicone oil retrieval, and one (1 eyes) had PFCL migration to the anterior chamber. No patients experienced sub-retinal/ sub-foveal PFCL or iatrogenic injury.ConclusionThis adjuvant drip-irrigative technique offers enhanced droplet visibility, reduced risk of iatrogenic retinal damage, and ease of application. Findings reported suggest the potential of this approach as a standard practice when using PFCL to mitigate complications.

Long-Term Functional Outcomes of Retinal Detachment Due to Acute Retinal Necrosis: A Case Series.

Objectives: To evaluate the long-term anatomical and functional prognosis of patients with retinal detachment (RD) secondary to acute retinal necrosis (ARN) treated with pars plana vitrectomy (PPV). Methods: This retrospective case series included 21 eyes from 21 patients with RD secondary to ARN. The study analyzed vitreous or aqueous biopsy results, the impact of antiviral therapy, time to retinal detachment, changes in visual acuity (VA), and anatomical and surgical outcomes. All cases underwent 23-gauge PPV with silicone oil tamponade, and an episcleral encircling band was used in 11 cases. All patients received systemic antiviral therapy at diagnosis. Results: Retinal reattachment was achieved in 91% of cases during follow-up, with an average follow-up period of 39.5 ± 36.8 months. The average time from ARN diagnosis to RD onset was 33.3 ± 27.5 days. VZV was detected in 10 eyes through PCR analysis. Significant differences in visual prognosis were found between macula-off and macula-on RD (p = 0.048). Eyes with optic nerve head inflammation had worse final VA (p = 0.010). No significant difference was observed between preoperative VA and VA at the end of follow-up (p = 0.665). Conclusions: VZV was the primary virus associated with ARN-related RD. Early involvement of the macula and optic nerve in retinitis negatively impacted the final visual prognosis.

Intravitreal Dexamethasone Implants for Macular Edema Secondary to Acute Retinal Necrosis

ABSTRACT Purpose To assess the effectiveness and risk of intravitreal injection of dexamethasone implants in treating macular edema (ME) secondary to acute retinal necrosis (ARN). Methods In this retrospective, noncomparative case series study, five patients who developed secondary ME after ARN and received an intravitreal dexamethasone implant injection were enrolled. The features of secondary ME on OCT and the outcomes of dexamethasone intravitreal implanting were presented. Results The mean age of the patients was 59 years (range, 51–61 years). All patients had unilateral involvement, and all 5 eyes showed mild to moderate anterior uveitis, retinal necrosis, and vasculitis. Herpes zoster virus was detected in all eyes using PCR, and timely antiviral and anti-inflammatory treatment was performed. Aqueous humor samples were negative for herpes zoster virus DNA, and resolution of viral retinitis was noted upon the occurrence of ME. Additionally, three eyes received pars plana vitrectomy with silicone oil prior to ME development. All eyes presented with intraretinal fluid, hyper-reflective foci, and impairments of the external limiting membrane/ellipsoid zone at varying degrees on OCT images. Epiretinal membrane was exhibited in 80% of eyes, but no vitreoretinal traction was detected. Subretinal fluid was visible in 60% of eyes. ME was relieved effectively in all eyes after intravitreal dexamethasone implanting. One of these patients experienced three episodes of ME. No recurrence of retinal necrosis or corticosteroid-associated ocular hypertension was observed during the follow-up period. Conclusion Intravitreal injection of dexamethasone implants can effectively alleviate ME secondary to ARN and improve visual acuity with no adverse reactions.

Accelerated failure behavior of Zr702 in boiling nitric acid solutions under constant stress loading

The constant stress tensile deformation behavior of commercial Zr702, used in spent fuel reprocessing industry, was investigated in 108 °C/200 MPa nitric acid solutions and non-corrosive silicone oil. Microscopic characterization of surface as well as cross-section of deformed Zr702 was carried out. In silicone oil, there were minimal cracks observed on the sample's surface. However, a significant number of cracks appeared on the sample's surface in nitric acid solutions. In nitric acid solutions, at the interface between the oxide layer and the matrix, cracks occurred, extended, the oxide film fractured, cracks further expanded, and the stress concentration at the cracks tip led to the formation of new cracks. This cyclic process resulted in the strength of the material decreasing and accelerated failure.

Cost Drivers of Pars Plana Vitrectomy for Retinal Detachment: Time-Driven Activity-Based Costing Analysis.

Introduction: To determine drivers of day-of-surgery costs for pars plana vitrectomy (PPV) in the management of retinal detachment (RD) repair, the mainstay treatment, based on surgical complexity and intraoperative factors. Methods: Economic analysis was performed using time-driven activity-based costing methodology for patients who had standard (Current Procedural Terminology [CPT] code 67108) or complex (CPT 67113) RD repair with PPV at the University of Michigan in 2021. Data were obtained via the electronic health record and previous literature. PPV expenses were determined with time-driven activity-based costing, a cost calculation that incorporates time and key resource costs, and were analyzed using univariate and multivariate regression. Results: The analysis included 412 PPVs (270 standard and 142 complex based on CPT code). The operating room time was significantly increased in complex cases (P < .01). Univariate analysis found that complex PPV, cryopexy, staining agent use, retinectomy, simultaneous scleral buckling, perfluoro-N-octane (PFO) use, silicone oil tamponade, and perfluoropropane tamponade were associated with a statistically significant difference in costs (P < .01); use of laser retinopexy was not significantly associated (P = .7190). Multivariate analysis found that standard PPV cost an average $5132.33 and significant incremental costs were found for complex PPV (+$1185.55; P < .001), cryopexy (+$465.02; P = .032), staining (+$525.16; P = .04), PFO use (+$1089.54; P < .0001), retinectomy (+$2031.17; P < .0001), and simultaneous scleral buckling (+$916.34; P = .006). Conclusions: The intraoperative factors that increase operating room time and ultimately the incurred cost of complex PPV cases vs standard PPV were identified and economically defined. These findings can improve practice patterns by optimizing costs for effective surgical planning in the management of RD repair.

Production of Monodisperse Large Drop Emulsions by Means of High Internal Phase Pickering Emulsions-Processing and Formulation.

High internal phase Pickering emulsions (HIPPE) have received significant research attention in the last two decades due to their potential for a wide range of applications. The appropriate processing of such high-viscosity emulsions, hundreds of times more viscous than that of the continuous phase, and the control of the final droplet size remain challenges to be tackled. Our research targeted this knowledge gap by examining the influence of the emulsion formulation and the processing conditions on the final droplet size. The dispersed phase fraction (100 cSt silicon oil) ranged between 75 and 80%. The emulsions were produced in a regular mixing tank equipped with a helical ribbon impeller rotating at a low speed (100-150 rpm). The effective viscosity of the continuous phase was obtained from the experimental torque measurements. The droplet size distributions were measured after emulsification and dilution in the continuous phases. It is shown that the capillary number obtained from the observed emulsification performance can help predict the final droplet size. Our approach provides a straightforward methodology to generate concentrated Pickering emulsions with controlled and predictable droplet size.

Flexible Triboelectric Sensor based on Catalyst‐Diffusion Self‐Encapsulated Conductive Liquid‐Metal‐Silicone Ink for Somatosensory Soft Robotic System

AbstractThe combination of fluidity and metallic conductivity has attracted considerable attention to liquid metal (LM), but its development remains challenging due to enormous surface tension. Here, vinyl‐terminated silicone oil and platinum catalyst are added to LM to reduce its surface tension, which develops a special type of liquid‐metal‐silicone (LMS) ink with a catalyst diffusion effect. Combined with an embedded three‐dimentional (3D) printing method, the LMS ink is printed on the support matrix, and the catalyst diffuses outward along the print path to cure the silicone around it, directly constructing self‐encapsulated conductive composites with excellent conductivity and self‐encapsulated flexible tactile sensors based on triboelectric nanogenerator (TENG). The sensor exhibits excellent sensitivity (0.308 V kPa−1), high linearity (≈0.99), and good durability (over 10 000 cycles). Furthermore, when used in flexible wearable electronics, the sensor demonstrates a good performance with an accuracy of ≈96% in classifying different human postures using a convolutional neural network. Finally, through embedded 3D printing with LMS ink and silicone ink, a somatosensory soft robotic gripper with complex cavity structures is designed and manufactured in one step, achieving the all‐in‐one integration of sensors and actuators. This study shows great application potential in flexible electronics and soft robotic systems.

Can Microcavitated Slippery Surfaces Outperform Micropillared and Untextured?

Surface features' morphology is crucial in designing lubricant-infused slippery surfaces (LIS). Microcavities were hypothesized to provide lower physical pinning, reduced droplet normal adhesion, and superior lubricant retention as compared to micropillars and untextured surfaces. Micropillars and microcavities (h = 10 ± 3 μm, d = 8 ± 1 μm, p = 17 ± 3 μm, rw = 1.4 ± 0.2) were replicated on polydimethylsiloxane from Lotus leaf and were coated with 1000 cSt silicone oil films (530 nm-27 μm thick). Water wetting, water-oil thermodynamic stability, droplet's normal adhesion and oil shear drainage properties were investigated to evaluate the relative performance of microcavitated, micropillared and untextured LIS. For ≤7 μm thick oil films, cavitated and untextured LIS displayed superior slippery properties than micropillared LIS (16 ± 1°, 7 ± 1°, 30 ± 4° slide-off angles respectively). Also, normal adhesion is of the order: cavities < untextured < pillars, and smaller than their dry counterparts. Furthermore, the oil retention efficiency under the action of centrifugal forces and continuous shear flow of water is of the order: pillars > cavities > untextured. Thus, it can be concluded that microcavitated LIS can outperform micropillared and untextured LIS.

Injectable Intravitreal Fluocinolone Acetonide Implant for Chronic Postoperative CME in the Presence of Silicone Oil Tamponade

Purpose: This report describes the use of the injectable intravitreal fluocinolone acetonide 0.18mg implant (FAI) for chronic postoperative cystoid macular edema (CME) in an eye with a silicone oil-filled vitreous cavity. Methods: A retrospective chart review was performed including surgical, clinical, and imaging data. Results: The patient had multiple complicated vitreoretinal surgical procedures including long-term silicone oil tamponade. The eye developed chronic CME, which responded to intravitreal steroid therapies and subsequently received FAI for longer-term control. The eye had no complications related to FAI. Conclusion: FAI is a long-acting steroid that may be beneficial in controlling chronic CME. It can be considered for use in eyes with silicone oil tamponade, but further studies are required to better understand the pharmacokinetics and utility of the FAI when injected into silicone oil-filled vitreous cavities.

"Sterile hypopyon following pars plana vitrectomy and silicone oil injection".

To report five cases of post-operative sterile endophthalmitis in patients who underwent pars plana vitrectomy with silicone oil injection for retinal detachment. Review of the medical records of five patients who underwent pars plana vitrectomy with silicone oil injection at Southend University Hospital and the Royal Eye Infirmary, Derriford Hospital for rhegmatogenous or tractional retinal detachment. All five patients presented with signs of anterior chamber inflammation exhibiting flare, fibrin and hypopyon in the early or late post-operative period following vitrectomy with silicone oil injection. Treatment with topical antibiotics and steroids was commenced, with rapid resolution of the anterior chamber inflammatory reaction and no further intervention required. The use of silicone oil as a tamponade agent for retinal detachment can rarely induce sterile anterior chamber inflammation with signs resembling infectious endophthalmitis. Onset of symptoms, absence of pain and good response to topical steroids can help differentiate between the two entities.

The role of vitreous cortex remnants in secondary macular hole formation and spontaneous closure following vitrectomy for rhegmatogenous retinal detachment

BackgroundMacular hole (MH) formation after rhegmatogenous retinal detachment (RRD) surgery is rare, and in most cases, additional surgical procedures are required to repair MH. Spontaneous closure of the MH is even rarer. In this study, we aimed to report a series of cases of spontaneous closure of the secondary MH and provide a review of the literature. MethodsWe retrospectively collected the cases of secondary MH formation following vitrectomy in RRD patients followed by spontaneous closure. Ophthalmological data at presentation and during follow-up were collected and analyzed. ResultsWe reported a total of three RRD patients aged 31,67,12 years, including two females and one male. The three patients underwent pars plana vitrectomy (PPV) with either silicone oil tamponade or air tamponade. Optical coherence tomography (OCT) revealed a second full-thickness MH formation with remnant vitreous cortex bridging in the macular region during early follow-up. Observations of the cases revealed subsequent remnant vitreous cortex traction remission and spontaneous closure of MH during follow-up, although with subsequent thin macular and abnormal macular structure. ConclusionThe progression of secondary MH formation in the cases may be related to vitreomacular traction (VMT) by the posterior vitreous cortex remnant after PPV, and the release of VMT may help the spontaneous closure of the MH after PPV for RRD.

A NOVEL USE OF FINESSE FLEX LOOP FOR PROLIFERATIVE VITREORETINOPATHY (FINESSE LOOP- ASSISTED PHOTOCOAGULATION)

Purpose: To describe a novel use of the flexible nitinol loop membrane scraper (Finesse Flex Loop; Alcon, Forth Worth, TX) for applying an effective endolaser photocoagulation in proliferative vitreoretinopathy (PVR) cases. Methods: A 27- gauge nitinol flex loop was used to assist applying endolaser photocoagulation to enhance its effectiveness in a case with PVR. Results: A 66-year-old female was presented with PVR after an unsuccessful pars plana vitrectomy and silicone oil injection for rhegmatogenous retinal detachment in her right eye. The patient underwent 25- gauge pars plana vitrectomy, preretinal membrane removal, inferior retinectomy, the nitinol flex loop assisted endolaser photocoagulation, and silicone oil reinjection. After the silicone oil extraction, the retina was reattached and her visual acuity had improved from 0.1 (20/200) to 0.3 (20/60). Conclusion: The nitinol flex loop can be used to assist endolaser photocoagulation and enhance its effectiveness in PVR cases and reduce the retinal excision area which results unnecessary large retinal defects that may lead to redetachment of the retina.

Cytotoxic Potencies of Zinc Oxide Nanoforms in A549 and J774 Cells.

Zinc oxide nanoparticles (NPs) are used in a wide range of consumer products and in biomedical applications, resulting in an increased production of these materials with potential for exposure, thus causing human health concerns. Although there are many reports on the size-related toxicity of ZnO NPs, the toxicity of different nanoforms of this chemical, toxicity mechanisms, and potency determinants need clarification to support health risk characterization. A set of well-characterized ZnO nanoforms (e.g., uncoated ca. 30, 45, and 53 nm; coated with silicon oil, stearic acid, and (3-aminopropyl) triethoxysilane) were screened for in vitro cytotoxicity in two cell types, human lung epithelial cells (A549), and mouse monocyte/macrophage (J774) cells. ZnO (bulk) and ZnCl2 served as reference particles. Cytotoxicity was examined 24 h post-exposure by measuring CTB (viability), ATP (energy metabolism), and %LDH released (membrane integrity). Cellular oxidative stress (GSH-GSSG) and secreted proteins (targeted multiplex assay) were analyzed. Zinc oxide nanoform type-, dose-, and cell type-specific cytotoxic responses were seen, along with cellular oxidative stress. Cell-secreted protein profiles suggested ZnO NP exposure-related perturbations in signaling pathways relevant to inflammation/cell injury and corresponding biological processes, namely reactive oxygen species generation and apoptosis/necrosis, for some nanoforms, consistent with cellular oxidative stress and ATP status. The size, surface area, agglomeration state and metal contents of these ZnO nanoforms appeared to be physicochemical determinants of particle potencies. These findings warrant further research on high-content "OMICs" to validate and resolve toxicity pathways related to exposure to nanoforms to advance health risk-assessment efforts and to inform on safer materials.

Experience in Application of the Combinations Dorzolamide / Timolol and Brinzolamide / Timolol for the Prevention of Intraocular Hypertension in Patients with Silicone Oil Tamponade of the Vitreal Cavity

Experience in Application of the Combinations Dorzolamide / Timolol and Brinzolamide / Timolol for the Prevention of Intraocular Hypertension in Patients with Silicone Oil Tamponade of the Vitreal Cavity

The Wisconsin silicone oil study (report #1): anatomical and functional outcomes of repair of retinal detachment with proliferative vitreoretinopathy.

Silicone oil (SO) is a long-term tamponade for repair of complex retinal pathology but has limitations including late redetachment. This study describes our experience with SO tamponade for repair of retinal detachment with proliferative vitreoretinopathy (PVR), with attention to anatomic and functional outcomes. Retrospective consecutive case series of eyes with retinal detachment (RD) complicated by proliferative vitreoretinopathy (PVR) receiving SO tamponade at the University of Wisconsin between 2013 and 2019. Group 1 defined as primary SO placement; Group 2 had SO placed after failing prior retinal detachment repair. Inclusion criteria of SO placement for repair of RD with PVR was met for 117 eyes. The final reattachment rate was 84% for all eyes, with no difference between Groups 1 and 2. Vision improvement was 2.1 lines for Group 1 (p = 0.06 from baseline) and 4.6 lines for Group 2 (p < 0.0001). The mean number of silicone oil placements was 1.4. Less improvement in vision was noted with repeat SO placement, though overall functional vision of 5/200 or better was achieved in 63.2% of patients. SO tamponade allows long-term anatomical stabilisation and substantial vision recovery in eyes with retinal detachment complicated by PVR. Rates of anatomic and functional success have improved significantly when compared to prior studies using oil tamponade for repair of PVR.

A Modified Intravitreal Methotrexate Protocol for the Prevention of Proliferative Vitreoretinopathy after Silicone Oil Removal

ObjectiveTo utilize a modified intravitreal (IVT) methotrexate (MTX) protocol for the prevention of proliferative vitreoretinopathy (PVR) after silicone oil (SO) removal (SOR). DesignSingle-center nonrandomized retrospective comparative case series. SubjectsEyes with grade C PVR who underwent retinal detachment repair and SO placement between 2019-2022 with at least 6 months of follow-up after SOR. A control group of age- and sex-matched eyes was included. MethodsEyes were treated with one of two MTX protocols. Eyes in Group 1 received 6 IVT MTX injections following SO placement, and another 6 IVT MTX injections following SOR. Eyes in Group 2 received 6 IVT MTX following SO placement only. Each series of 6 IVT MTX injections (400 μg/0.1 mL) consisted of 3 injections every 2 weeks followed by 3 injections every 4 weeks. Main Outcome MeasuresThe primary outcome was the retinal attachment rate at 6 months post-SOR without re-detachment or re-operation. Secondary outcomes included change in visual acuity (VA) and rates of complications after SOR. ResultsFifty-two eyes of 52 patients (13 Group 1, 13 Group 2, 26 control) (mean age 59.8 years, 80.8% male) were included with a mean follow-up of 31.0 months. In aggregate, Group 1 and Group 2 eyes received a median (IQR) of 6 (5.25, 7) IVT MTX injections pre-SOR; eyes in Group 1 received a median (IQR) of 5 (3, 6) IVT MTX injections post-SOR. Twelve (92.3%) Group 1 eyes, 11 (84.6%) Group 2 eyes, and 21 (80.8%) control eyes had primary retinal attachment at 6 months post-SOR (P > 0.05). VA outcomes did not significantly differ between groups (P > 0.05). Rates of epiretinal membrane (ERM) and cystoid macular edema (CME) were significantly lower in Group 1 eyes (7.7% and 15.4%) compared to Group 2 (53.8% and 92.3%) and control (44.3% and 65.4%) eyes, respectively (P < 0.05). ConclusionsThe use of IVT MTX injections in eyes with PVR undergoing RD repair was associated with a high rate of primary retinal attachment after SOR. Eyes that received IVT MTX injections after SOR had significantly lower rates of ERM and CME than eyes that did not.

Single-layer iron network microstructure magnetorheological elastomer for transparent soft actuator

The motion of a soft magnetic magnetorheological elastomer, a composite material consisting of soft magnetic fillers and an elastomeric matrix, is limited by the gradient of the applied magnetic field, making its application as an out-of-plane soft actuator difficult. In this study, an anisotropic soft magnetic magnetorheological elastomer-based transparent soft actuator with large out-of-plane deformation was fabricated using a very low concentration (1 vol%) of carbonyl iron particles as the soft magnetic fillers. An applied AC electric field treatment method was used to manipulate iron particles in silicone oil, assembling and depositing them onto a glass substrate to form a single-layer iron-network microstructure. A single-layer iron-network microstructure-based magnetorheological elastomer (SL-sMRE) film with initial self-buckling was fabricated by exploiting the swelling properties of the residual silicone oil and polydimethylsiloxane. The SL-sMRE film exhibited out-of-plane deformation with a very short reaction time (228 ms) under a uniform magnetic field. When stimulated by a non-uniform magnetic field, the SL-sMRE film deformed away from the permanent magnet, which was not possible with an isotropic film. An optically transparent SL-sMRE film was applied to a transparent flexible gripping device that could detect the surface of a gripped object in real time.

Anti-icing performance of SLIPSs injected with different lubricants

Abstract Transmission line icing is seriously threatening the power grid to operate safely. Slippery Liquid-infused Porous Surface (SLIPS) is a latent application to solve transmission line ice cover. The matrix structure and lubricant are important components of SLIPS. However, a variety of lubricants have been used to prepare SLIPS, and there is a lack of certain theoretical guidance for selecting lubricants to prepare anti-icing SLIPS. In this paper, the effects of three lubricants on the wettability, anti-icing performance, and anti-icing durability of SLIPS were investigated. It was found that dimethyl silicone oil was more favorable for preparing anti-icing SLIPS. The SLIPS prepared from silicone oil had a complete frosting time of about 10 min longer than that of mineral oil and safflower oil and had the lowest ice adhesion strength of 4.5 ± 0.8 kPa. It also has better anti-icing durability; even after 30 repetitions of icing/deicing, ice adhesion strength is still below 20 kPa.