Viscoelastic, Optical, and Surgical Properties of Vitreous Body Replacement Hydrogels After Aging Compared to Porcine Vitreous Bodies And Silicone Oils.

Purpose: First- (monomers), second- (pre-gelated), and third- (in situ gelating after injection) generation hydrogels were previously introduced to replace the vitreous body after vitrectomy surgery. In this study, we evaluated the surgical, optical, and viscoelastic properties of vitreous body replacement hydrogels before and after an accelerated aging protocol previously applied to intraocular implants. Methods: Measurements of injection force, removal speed using a clinically established vitrectomy setup, as well as evaluation of forward light scattering and viscoelastic properties before and after an accelerated aging protocol were conducted. Results were compared to porcine and human vitreous bodies, as well as currently clinically applied lighter- and heavier-than-water silicone oils. Results: Removal speed of all tested hydrogels is substantially lower than the removal speed of porcine vitreous body (0.2 g/min vs. 2.7 g/min for the best performing hydrogel and porcine vitreous body, respectively). Forward light scattering in second-generation vitreous body replacement hydrogels was higher after the aging process than the straylight of the average 70-year-old vitreous body (9.4 vs. 5.5 deg2/sr, respectively). The viscoelastic properties of all hydrogels did not change in a clinically meaningful manner; however, trends toward greater stiffness and greater elasticity after aging were apparent. Conclusions: This study demonstrates surgical weaknesses of the hydrogels that need to be addressed before clinical use, especially low removal speed. Pre-linked hydrogels (second-generation) showed inferior performance regarding surgical properties compared to in situ gelating hydrogels (third-generation). Translational Relevance: This study highlights possible pitfalls regarding surgical and optical properties when applying vitreous replacement hydrogels clinically.

Examining the etiological factors resulting in retinal detachment following prophylactic vitrectomy in the context of acute retinal necrosis syndrome.

OBJECTIVE: The aim of this study is to elucidate the factors contributing to the occurrence of retinal detachment (RD) following prophylactic vitrectomy in cases of acute retinal necrosis (ARN) syndrome. METHODS: A retrospective examination was undertaken, encompassing the medical records of patients diagnosed with ARN who underwent prophylactic vitreous intervention at the Ophthalmology Department of Wuhan University Renmin Hospital East Campus between October 2019 and September 2023. Subsequently, patients who manifested RD in the postoperative period were identified, and a comprehensive analysis was conducted to ascertain the factors underlying the occurrence of RD post-surgery. RESULTS: This study comprised 14 cases (involving 14 eyes) of patients diagnosed with ARN who underwent prophylactic vitreous intervention. The findings revealed that 4 patients experienced postoperative RD, resulting in an incidence rate of 28.57%. Notably, among these cases, 3 cases of RD manifested in the presence of silicone oil, while 1 case occurred subsequent to the removal of silicone oil. All 4 cases of RD exhibited varied degrees of proliferative vitreoretinopathy. Following the occurrence of RD, all patients underwent a secondary vitreous intervention coupled with silicone oil tamponade, leading to successful reattachment of the retina. However, despite these interventions, there was no significant enhancement observed in postoperative visual outcomes when compared to preoperative levels. CONCLUSION: RD following prophylactic vitrectomy in cases of ARN is not an infrequent occurrence and is primarily linked to the postoperative onset of proliferative vitreoretinopathy.

Application of High-Frequency Ultrasound to Evaluate Forehead Filling Materials.

BACKGROUND: In recent years, soft tissue materials have been applied as forehead fillers. Some filling materials need to be removed or refilled in a timely manner in certain situations; therefore, it is important to develop a method to identify the location and type of filling materials. This study summarizes the imaging findings of different filling materials under high-frequency ultrasound, providing a reference for clinical treatment. METHODS: We screened facial ultrasound images performed at the Plastic Surgery Hospital of the Chinese Academy of Medical Sciences from April 2015 to July 2023 and classified and summarized the types of frontal filling materials and their imaging results. RESULTS: This study included ultrasound imaging results from 114 patients, including 39 with hyaluronic acid (HA) filling, 45 with polyacrylamide hydrogel (PAG) filling, 14 who received autologous fat transplantation, 2 who received prosthesis implantation, 2 who received both HA and PAG filling, and 12 who received silicone oil filling. HA mainly manifests as an anechoic zone on ultrasonography, with images divisible into four types. PAG primarily presents as fine punctate echoes, divisible into five types. Fat transplantation presents as a low-echo area with uneven density, divisible into five types. Finally, the silicone oil-filling material appears as a cloud-like high echo on the forehead, visible throughout the entire skin layer, and unclear imaging in deep tissues. CONCLUSION: High-frequency ultrasound is a safe and reliable method to evaluate the type and position of forehead filling materials, which can be easily applied in clinical practice. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

[Translated article] Syringes for intraocular administration: A systematic review.

OBJECTIVE: The off-label use in clinical practice of non-approved syringes for intravitreal drug administration has resulted in the detection of silicone oil drops in the vitreous of some patients. This situation derives from the lack of approved syringes for intraocular use in the Spanish market. The aim of this work is to review the use of syringes for intraocular administration, as well as to search for alternatives that meet the legal requirements for these unmet needs. METHOD: A systematic review was performed following the PRISMA 2020 guidelines by searching PubMed with the descriptors: (silicone) AND (syringes) AND ((intraocular) OR (intravitreal)) and filtering all existing publications from January 2006 to December 2023, including all those articles dealing with silicone oil release in intravitreal injections and analysing the possible consequences. RESULTS: Sixty-eight results were found, 23 of which were excluded because they did not deal with the subject under study, leaving a total of 45 articles for the systematic review. These were classified according to the conclusions obtained in 4 groups: the adverse reactions produced by silicone; the administration technique; the physicochemical aspects of silicone release; and the characteristics of the medical device. After reviewing the current manufacturers and technical data sheets of commercialised syringes, the existing syringes for this use have been collected, finding 2 that will probably be commercialised in Spain at the beginning of 2024: Zero Residual™ 0.2 ml SiO-free and VitreJect® Ophthalmic. CONCLUSIONS: From the results obtained, it can be interpreted that the use of syringes and needles with silicone for intravitreal use is a concern for health professionals due to the implications and consequences that may arise in patients, the most important being adverse reactions, so it is necessary to have silicone-free syringes on the market that are specific for intraocular use. Safety and legality in the use of intraocular syringes and needles is essential to guarantee ocular integrity and patient health.

Studies on cationic ocular emulsions containing bipartitioned oil droplets to codeliver cyclosporin A and etodolac.

Background: To prepare ocular emulsions containing bipartitioned oil droplets to entrap cyclosporin A (0.05% w/w) and etodolac (0.2% w/w) by using castor, olive and silicon oils. Methods: The physicochemical characterizations of prepared emulsions were performed. The drug's biodistribution profiles and pharmacokinetic parameters from emulsions were checked using the ultraperformance liquid chromatography-tandem mass spectrometry method in the ocular tissues of the healthy rabbit eye model. Results: The emulsions displayed 365.13 ± 7.21 nm size and 26.45 ± 2.09 mV zeta potential. The ferrying of two drugs after releasing from emulsions occurred across corneal/conjunctival tissues to enter the vitreous and sclera following a single drop administration into the rabbit's eyes. Conclusion: The dual drug-loaded emulsions were more likely to produce synergistic anti-inflammatory activity for managing moderate-to-severe dry eye disease.

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Comparison of clinical performance of obturating materials in pulpectomies: A randomized clinical trial.

BACKGROUND: Chemomechanical debridement is insufficient to disinfect all bacteria from the root canals of primary teeth, and obturation of canals with an appropriate material thus acquires excellent importance and remains a critical step in the ultimate success of pulpectomy. AIM: The aim of the study was to compare and evaluate Endoflas, Metapex, and a mixture of calcium hydroxide (CH) and zinc oxide (ZnO) as obturating materials (OMs) in primary mandibular second molars. MATERIALS AND METHODS: Seventy-five mandibular second primary molars requiring pulpectomies were identified in children aged 4-8 years. They were randomly allocated to the three treatment groups according to the type of OM received using the block randomization technique. After the completion of chemomechanical debridement, the canals were filled with Endoflas, Metapex, and CH-ZnO mixture, respectively. The intergroup clinical and radiographic comparison was made based on Coll and Sadrian criteria to decipher their clinical performance at 1, 3, and 6 months. RESULTS: No statistically significant differences between the groups were observed at any evaluation time interval (P > 0.05). At 6 months, the clinical success rates were 95.2% in Endoflas, 96% in Metapex, and 95.8% in the CH and ZnO mixture groups, respectively. The materials, however, behaved differently in different clinical situations. CONCLUSION: Based on the observations, all three OMs showed similar clinical success in maintaining tooth functioning, but their use can be restricted to indications. However, prospective studies with longer follow-ups with more stringent eligibility criteria are required to reach more definitive conclusions.

Surgical management of a case of giant retinal tear with closed funnel retinal detachment in a pediatric patient.

BACKGROUND: A 7-year-old male child was brought by his parents with a complaint of low vision in both eyes for 2 months. The child had low vision in both the eyes for 1.5 years, but the parents noticed when it worsened further 2 months back, leading to profound vision loss. On ophthalmic evaluation, the child did not perceive light in the right eye. Furthermore, anterior segment examination showed complicated cataract and open funnel retinal detachment with intra-retinal cysts in ultrasound (USG) B scan. In the left eye, he could appreciate light but with poor fixation. Fundus evaluation of the left eye showed total retinal detachment on indirect ophthalmoscopy, which was confirmed on USG B scan. Since the right eye had poor visual potential, no intervention was done. The left eye underwent pars plana vitrectomy with silicone oil tamponade, which led to successful anatomical outcomes. The immediate and late postoperative periods were uneventful, and the child was kept under follow-up and was observed closely. PURPOSE: To educate regarding the surgical management of giant retinal tears in a pediatric patient. SYNOPSIS: To inform regarding the surgical challenges faced and steps adopted to manage such cases. HIGHLIGHTS: Through this case, we want to highlight the challenges faced, such as delayed presentation, difficult preoperative evaluation, intraoperative difficulties such as mobile retina, absence of posterior vitreous detachment, and tenacious vitreous gel. We also want to emphasize on the steps taken to overcome the challenges. CONCLUSION: In such challenging situations, effective planning, careful manipulation, and persistence are essential for success. VIDEO LINK: https://youtu.be/T0Gy6Wj13zI.

Impact of duration of silicone oil tamponade on foveal and parafoveal thickness in rhegmatogenous retinal detachment: a retrospective cohort study.

PURPOSE: To detect and analyze the influence of the duration of tamponade with silicone oil on the foveal and parafoveal thickness in cases of rhegmatogenous retinal detachment. METHODS: This is a retrospective cohort study of 64 eyes with rhegmatogenous retinal detachment in one eye who underwent pars plana vitrectomy (PPV) with silicone oil injection during the period between January 2019 and December 2021. The patients were divided into 2 groups. Group A with early removal of the silicone oil after 3-4 months and Group B with late removal of the silicone oil (SOR) after 6-8 months. The 2 groups were compared as regards the central foveal (CFT) and parafoveal (PFT) thickness changes from baseline, just before SOR, and after SOR. Changes in best corrected visual acuity (BCVA), relative risk of severe thinning. It was conducted at Kasr Alainy Hospital. RESULTS: 64 eyes were enrolled in the study. Group A included 36 eyes, and group B included 28 eyes. The mean CFT changed insignificantly from 253 ± 52 µm to 252 ± 48 µm after SOR in group A; while it changed significantly from 211 ± 52 µm to 202 ± 46 µm after SOR in group B. The mean PFT decreased insignificantly from 299 ± 39 µm to 297 ± 40 µm in group A, while it decreased significantly from 284 ± 46 µm to 273 ± 44 µm in group B. Lines of improvement of BCVA were 4.11 ± 1.88 in group A, and 2.00 ± 1.24 in group B. Relative risk of severe foveal thinning after SOR was 14.3, and severe parafoveal thinning was 15.43, in group B compared to group A. CONCLUSION: Longer period of silicone oil tamponade may carry a higher risk for severe foveal and parafoveal thinning after silicone oil removal. TRIAL REGISTRATION: The study was registered at clinical trial.gov under the title of (Duration of silicone oil tamponade on foveal and parafoveal thickness in Rhegmatogenous Retinal Detachment) with an ID NCT05817630 at April 2023 "retrospectively registered".

Silicone Oil Tamponade for Therapy of Primary Retinal Detachment in Patients Who Live at High Altitudes.

BACKGROUND: Uncomplicated rhegmatogenous retinal detachment (RRD) is mainly treated with vitrectomy and gas tamponade or, alternatively, scleral buckling surgery. However, gas tamponade inflates at high altitudes, causing significant complications. Silicone oil (SO) tamponade volume is unaffected by atmospheric pressure and may be used in patients who live or must undertake travel at high altitudes. PURPOSE: To determine the anatomical and functional outcomes after pars plana vitrectomy (PPV) with SO tamponade in primary uncomplicated RRD. METHODS: Twenty-eight consecutive cases of patients operated between January 2017 and December 2022 in Jules-Gonin University Eye Hospital in Lausanne were included in this retrospective study. All patients had a follow-up of at least 3 months after SO removal. RESULTS: Primary reattachment was achieved in all 28 eyes. Mean follow-up was 17.2 months (range: 3 - 51 months) after SO removal. Mean age at the time of intervention was 60 years (range: 21 - 80 years). Vision was stabilized or improved in 27 eyes (96%). One patient demonstrated a slight visual acuity decrease due to cataract formation at the last follow-up. In all patients, SO was removed 2 to 5 months after primary repair. In 14 of the 21 phakic patients, concomitant cataract surgery was performed. No surgical complications were encountered. Postoperatively, 5 (18%) patients had ocular hypertension, presumably steroid related, that was successfully controlled with topical treatment. CONCLUSION: PPV with SO injection seems to be a safe and efficient surgical approach in the treatment of primary uncomplicated RRD in patients living at high altitudes and was associated with good anatomical and functional outcome in our series. However, the need for a follow-up surgery to remove SO should be weighed in these cases.

Management of macula-on giant retinal tear detachments- outcome of pars-plana-vitrectomy with silicone oil versus gas tamponade.

BACKGROUND: To compare the outcome of eyes with a macula-on giant retinal tear (GRT) detachment treated with pars-plana-vitrectomy (PPV) depending on the used endotamponade. METHODS: All consecutive cases with a macula-on GRT-associated rhegmatogenous retinal detachment (RRD) managed with PPV between 2007 and 2022 were retrospectively assessed depending on the selected endotamponade. By reviewing medical charts and surgical protocols the pre- and intraoperative parameters were analysed in detail. The number of vitreoretinal (VR) procedures needed for reattachment, the redetachment rate and the functional outcome were evaluated. Eyes treated with primary silicone oil (SO) tamponade were compared to eyes with primary gas tamponade. Cases with pre-existing conditions affecting outcome e.g. macula-off situation, history of trauma, status after complicated cataract surgery, former VR surgery or proliferative vitreoretinopathy grade C or higher were excluded. RESULTS: Overall, 51 eyes of 45 patients with a macula-on GRT detachment were treated with PPV and SO (n = 32; 63%) or gas (n = 19; 37%) endotamponade in the observed period. Eyes with primary SO tamponade underwent on average 2.3 (SD 0.8) VR procedures and had a redetachment rate of 13% (n = 4). Eyes with gas tamponade showed a higher redetachment rate of 32% (n = 6) with a mean number of 1.6 (SD 1.0) PPV procedures. Postoperative best-corrected visual acuity (BCVA) was significantly better in eyes with primary gas tamponade (mean logMAR BCVA 0.32; SD 0.30) compared to eyes with SO (mean logMAR BCVA 0.60; SD 0.42; p = 0.008). CONCLUSIONS: Surgical management of GRT-associated RRDs is complex. In clinical routine often SO is used as endotamponade. Because of known disadvantages (second procedure necessary for SO removal, unexplained SO-related visual loss, secondary glaucoma, SO emulsification) some VR surgeons prefer a gas tamponade. In our cohort, eyes with a gas compared to SO tamponade showed higher redetachment rates. However, the final postoperative BCVA was significantly better in eyes with gas compared to SO tamponade. TRIAL REGISTRATION: The trial protocol was approved by the local ethics committee on 25th of November 2022 (Ethikkommission der Universität Regensburg, Votum 22-3166-104).

Macular edema after surgery to treat rhegmatogenous retinal detachment: 1-year follow-up, incidence, and associated risk factors.

PURPOSE: To clarify the postoperative incidence of macular edema in patients undergoing surgery to repair rhegmatogenous retinal detachment and identify the associated risk factors. METHODS: In this prospective, observational study, 79 patients who underwent surgery to correct rhegmatogenous retinal detachment using pars plana vitrectomy with silicone oil injection were analyzed. Patients were followed up postoperatively at 7, 30, 90, 180, and 365 days. At each visit, optical coherence tomography was performed to assess the presence or absence of macular edema. were analyzed as possible risk factors for macular edema: age, sex, macular status (attached or detached), presence of vitreoretinal proliferation, history of previous intraocular surgery, reported time of symptoms suggestive of rhegmatogenous retinal detachment up to the date of surgery, and the surgical modality performed. RESULTS: The 1-year macular edema prevalence rate was 26.6%. In the adjusted analysis, older patients had a higher risk of macular edema, and each 1-year increase in age increased the risk of macular edema by 6% (95% confidence interval = 1.00-1.12). The macular status, vitreoretinal proliferation, the surgical technique used, prior intraocular surgery, and the intraocular lens status were not identified as risk factors. However, the incidence of macular edema increased up to 180 days after surgery, peaking at 10.6%, and then decreased until 365 days after surgery. CONCLUSION: Macular edema was a common complication after surgery to treat rhegmatogenous retinal detachment, with its incidence peaking between 30 and 180 days after surgery. Age was an important risk factor for macular edema in this cohort.

Refinements in the use of silicone oil as an intraocular tamponade.

It is over 60 years since Paul Cibis et al. reported the experimental use of liquid silicone in the surgical management of retinal detachment. Initial experiences were complicated by significant side-effects associated with the impurities in the non-medical grade commercial silicone oils deployed at the time. These were substantially reduced (but not eliminated) by the adoption of refined high-viscosity medical grade silicone oils. Two of the major complications associated with silicone tamponade are (i) the variability of focus due to its movement and higher refractive index, and (ii) progressive emulsification, particularly with low viscosity oils. This article reviews recent and ongoing research on the causes of emulsification of intra-ocular silicone oil to understand the causes better and thereby reduce this risk, especially for those eyes where permanent tamponade is the only current option for retaining vision.

FUNCTIONAL AND ANATOMICAL OUTCOMES AFTER SHORT-TERM HEAVY SILICONE OIL ENDOTAMPONADE FOR INFERIOR RHEGMATOGENOUS RETINAL REDETACHMENT: A Pilot Study.

PURPOSE: To assess the success of the short-term location of the heavy silicone oil (Densiron 68, HSO) as endotamponade after pars plana vitrectomy for rhegmatogenous complex retinal redetachment. METHODS: Consecutive, retrospective, nonrandomized, pilot study was conducted. Twenty-two eyes of 22 patients with complex inferior retinal redetachment previously tamponade with gas (SF6 or C3F8) or 1000 cSt standard silicone oil (SSO) were selected. All were treated with HSO endotamponade, and its removal was performed after 1 month. The main outcomes were best-corrected visual acuity and postoperative complications after the HSO removal. RESULTS: Of the 22 eyes, 10 were treated with SSO endotamponade, 3 with fluorinated gas 14% C3F8, and 9 with 20% SF6 at first surgery. In all eyes, a complex inferior retinal redetachment was observed after the first surgery, in 1 month to 3 months after silicone oil removal or gas endotamponade introduction. In 10 eyes, the proliferative vitreoretinopathy (Grade B or C 1-3) was found. The main best-corrected visual acuity before HSO removal was 0.55 ± 0.20 the logarithm of the minimum angle of resolution (range 0.4-0.7) and after the HSO removal, it was 0.32 ± 0.29 the logarithm of the minimum angle of resolution (0.1-0.4). Among the postoperative complications, only in four eyes the macular edema was found (medically resolved), in four eyes an increase of intraocular pressure, and none of these developed the epiretinal membrane. CONCLUSION: The main purpose of this study is to establish a short-term HSO endotamponade in eyes with complex retinal detachment recurrences, reducing the possible postoperative complications and having a better prognosis for visual acuity outcomes.

Inverted Internal Limiting Membrane Flap Coverage With Autologous Blood Technique After Air-Fluid Exchange and Silicone Oil Tamponade for Extensive Macular Hole Retinal Detachment in Highly Myopic Eyes.

PURPOSE: To report a technique consisting of inverted internal limiting membrane (ILM) flap coverage with autologous blood after air-fluid exchange and silicone oil tamponade in treating extensive retinal detachment secondary to a myopic macular hole (MH). METHODS: This was a retrospective case series. 18 eyes with MHRD extending beyond the equator were included in this study with a minimum follow-up of 6 months. The procedures for pars plan vitrectomy (PPV) included the following: 1) The ILM was peeled to the superior and inferior arcade margins and, except for the ILM in the temporal region, was hinged toward the edge of the MH. 2) Air-fluid exchange was then performed to drain the subretinal fluid through the MH with a flute needle, ensuring that a small amount of subretinal fluid remained to facilitate ILM flap inversion. 3) The ILM flap was used to cover the MH with the assistance of autologous blood. RESULTS: Six months after surgery, the MH was successfully anatomically closed, and retinal reattachment was observed in all 18 eyes of 18 patients. The mean best-corrected visual acuity logarithm of the minimum angle of resolution (logMAR) improved from 2.03 ± 0.61 (ranging from hand motion [2.6] to finger counting [2.3]) to 1.23 ± 0.63 (ranging from hand motion [2.6] to 20/28 [0.15]) ( P < 0.01) at 6 months. CONCLUSION: This surgical technique using an inverted ILM flap combined with autologous blood provides an option for the treatment of extensive MHRD.

Hydroxyl silicone oil grafting onto a rough thermoplastic polyurethane surface created durable super-hydrophobicity.

Indwelling medical catheters are frequently utilized in medical procedures, but they are highly susceptible to infection, posing a vital challenge for both health workers and patients. In this study, the superhydrophobic micro-nanostructure surface was constructed on the surface of thermoplastic polyurethane (TPU) membrane using heavy calcium carbonate (CaCO3) template. To decrease the surface free energy, hydroxyl silicone oil was grafted onto the surface, forming a super-hydrophobic surface. The water contact angle (WCA) increased from 91.1° to 143 ± 3° when the concentration of heavy calcium CaCO3 was 20% (weight-to-volume (w/v)). However, the increased WCA was unstable and tended to decrease over time. After grafting hydroxyl silicone oil, the WCA rose to 152.05 ± 1.62° and remained consistently high for a period of 30 min. Attenuated total reflection infrared spectroscopy (ATR-FTIR) analysis revealed a chemical crosslinking between silicone oil and the surface of TPU. Furthermore, Scanning electron microscope (SEM) image showed the presence of numerous nanoparticles on the micro surface. Atomic force microscope (AFM) testing indicated a significant improvement in surface roughness. This method of creating a hydrophobic surface demonstrated several advantages, including resistance to cell, bacterial, protein, and platelet adhesion and good biosecurity. Therefore, it holds promising potential for application in the development of TPU-based medical catheters with antibacterial properties.

Contamination Profile of Different Formulations of Silicone Oil Tamponade Before and After Intraocular Permanence for Rhegmatogenous Retinal Detachment.

Purpose: The purpose of this study was to search for contaminants in silicone oil tamponades removed from eyes treated for retinal detachment, and to correlate chemical results with some clinical/functional parameters of the considered eyes. Methods: We examined a sequential cohort of eyes grouped according to the tamponade received: (1) Siluron2000 (S2), (2) RS-OIL ECS5000 (S5), and (3) Densiron Xtra (DX). Samples were collected at the beginning of the scheduled removal and analyzed by untargeted headspace gas-chromatography mass spectrometry (HS-GC-MS). Visual acuity and optic coherence tomography assessments were obtained before and after the tamponade removal. Results: Forty-one samples were analyzed: 22 belonging to the DX group, 13 to the S2 group, and 6 to the S5 group. For each group, a mixture of uninjected commercial preparation was analyzed as the reference. Different siloxanes and fluorinated compounds including perfluorodecalin (PFCL) were the most prevalent chemicals, found in 55% to 100% of the intraocular samples of the 3 groups. Some siloxanes were present also in the control matrices, whereas PFCL was only in the extracted tamponades. In the DX group, the concentration of hexamethylcyclotrisiloxane showed an inverse correlation trend with the duration of its permanence inside the eye (P = 0.054). Different alkanes, propanol, and acetaldehyde were identified only in the control matrices. Conclusions: Several contaminants including siloxanes were identified in the intraocular samples and in the control matrices. A time-related ocular uptake of some of these is conceivable. PFCL was also highly present but only in intraocular samples. Translational Relevance: After intraocular permanence silicone oils (SOs) have various unlabeled contaminants with some relevant differences with the commercial formulation chemical profile.

Effect of silicone oil versus gas tamponade on macular layer microstructure after pars plana vitrectomy for macula on rhegmatogenous retinal detachment.

PURPOSE: To analyze structural changes in the macular retinal layers and sub-foveal choroidal thickness (SFCT) in eyes after macula-on rhegmatogenous retinal detachment (RRD) repair by pars plana vitrectomy with either silicone oil (SO) or gas tamponade, and the effect of these changes on visual acuity. PATIENTS AND METHODS: Retrospective study which included 26 eyes in the SO Group and 32 in the Gas Group. Optical coherence tomography (OCT) scans of the affected eyes were obtained before surgery, and 3 months after PPV in the Gas Group, and during silicone oil in situ and 3 months after SO removal, in the SO Group. Qualitative assessment of photoreceptor layer and foveal contour, along with quantitative assessment of macular retinal thickness and SFCT was performed. Postoperative OCT macular microstructural changes were recorded and correlated to corrected distance visual acuity (CDVA). Intraocular pressure (IOP) was measured preoperative and at 3 months post operative. RESULTS: There was a 2-line loss (from 20/28 preoperatively to 20/40 at final follow-up) of CDVA in the SO Group (p=0.051), while there was no statistically significant change in CDVA in the Gas Group (p=0.786). There was no significant correlation between CDVA loss and duration of silicon tamponade (r=-0.031, p=0.893). There was a statistically significant increase in IOP from its baseline to final follow-up of 0.7 mmHg in the SO Group (p=0.023) while there was no statistically significant change in IOP in the Gas Group. During silicone oil tamponade, there was approximately 11% and 5% of retinal and sub-foveal choroidal thinning respectively, which was moderately resolved following silicone oil removal. 20% (5/24) of eyes in the SO Group had qualitative flattening of foveal contour during SO tamponade that resolved after SO removal. CONCLUSION: Thinning of the macula was noticed after macula-on RRD repair with SO tamponade. Such thinning was only partially reversible after the removal of SO.

Silicone-geranium essential oil blend for long-term antifouling coatings.

This study explores the potential of geranium essential oil as a natural solution for combating marine biofouling, addressing the environmental concerns associated with commercial antifouling coatings. Compounds with bactericidal activities were identified by 13Carbon nuclear magnetic resonance (13C NMR). Thermogravimetric analysis (TGA) revealed minimal impact on film thermal stability, maintaining suitability for antifouling applications. The addition of essential oil induced changes in the morphology of the film and Fourier transform infrared spectroscopy (FTIR) analysis indicated that oil remained within the film. Optical microscopy showed an increase in coating porosity after immersion in a marine environment. A total of 18 bacterial colonies were isolated, with Psychrobacter adeliensis and Shewanella algidipiscicola being the predominant biofilm-forming species. The geranium essential oil-based coating demonstrated the ability to reduce the formation of Psychrobacter adeliensis biofilms and effectively inhibit macrofouling adhesion for a duration of 11 months.