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-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.

Transparent silicone-free shampoo containing proteins with strong hair conditioning properties.

OBJECTIVE: With the constant upgrading of healthcare concepts, silicone-free hair products have attracted more attention among consumers. In the present study, transparent silicone-free shampoo containing proteins was successfully fabricated by mixing mild non-sulphate surfactants, compound cationic conditioners, natural silicone oil substitutes, protein conditioners, thickeners, and other auxiliary ingredients. The effects of the type of surfactants, hair conditioners and thickeners, the type and content of proteins, and the mass ratio of compound proteins on the hair foaming performance, hair grooming performance, and penetration performance were investigated. METHODS: The basic formulation framework for transparent silicone-free shampoo was established at first. Then, various hydrolyzed proteins were further added to the basic formulation in the form of single use or compound use to prepare transparent silicone-free shampoo containing different proteins. The morphology of hair samples and penetration of protein in hair were evaluated with a scanning electron microscope and laser confocal fluorescence microscopy, respectively. And the hair grooming performance was also determined by a dynamic combing tester. RESULTS: The compound proteins of Croquat WKP PE-LQ-WD and Gluadin® Kera-PLM with mass ratios of 1:9 and 1:1 at 2 wt% total protein content added to the silicone-free shampoo brought a higher contact angle and a lower frictional coefficient than commercial silicone-free shampoo without proteins. In addition, the compound proteins also have the dual effect of adsorbing the hair surface and penetrating deep into the interior of the hair. CONCLUSION: The combination of cationic modified hydrolyzed protein (e.g., Croquat WKP PE-LQ-WD) and hydrolyzed protein with low molecular weight (e.g., Gluadin® Kera-P LM) at an appropriate mass ratio exhibited a strong synergistic effect on hair conditioning properties. It could provide a significant reference for developing silicone-free hair products with more benefits.

OBJECTIF: Avec l'amélioration constante des concepts de soins de santé, les produits capillaires sans silicone ont attiré l'attention des consommateurs. Dans la présente étude, un shampooing transparent sans silicone contenant des protéines a été fabriqué avec succès en mélangeant des tensioactifs doux sans sulfate, des conditionneurs cationiques composés, des substituts naturels de l'huile de silicone, des conditionneurs protéiques, des épaississants et d'autres ingrédients auxiliaires. On a étudié les effets du type de tensioactifs, de conditionneurs pour les cheveux et d'épaississants, du type et de la teneur en protéines et du rapport massique des protéines composées sur les performances de moussage des cheveux, du nettoyage des cheveux et de la pénétration. MÉTHODES: le cadre de formulation de base pour le shampooing transparent sans silicone a d'abord été établi. Ensuite, diverses protéines hydrolysées ont été ajoutées à la formulation de base sous forme d'utilisation unique ou d'utilisation de composés pour préparer un shampooing transparent sans silicone contenant différentes protéines. La morphologie des échantillons de cheveux et la pénétration des protéines dans les cheveux ont été évaluées à l'aide d'un microscope électronique a balayage et d'une microscopie confocale laser à fluorescence, respectivement. Les performances de nettoyage des cheveux ont également été déterminées par un testeur de peignage dynamique. RÉSULTATS: les protéines composées de Croquat WKP PE-LQ-WD et de GluadinR Kera-PLM avec des rapports massiques de 1:9 et 1:1 à 2 % en poids de teneur en protéines totales ajoutées au shampooing sans silicone ont un angle de contact plus élevé et un coefficient de frottement plus faible que le shampooing sans silicone commercial sans protéines. En outre, les protéines composées ont également doublé l'effet d'adsorption à la surface des cheveux et de pénétration à l'intérieur des cheveux. CONCLUSION: la combinaison de protéines hydrolysées modifiées cationiques (par exemple, Croquat WKP PE-LQ-WD) et de protéines hydrolysées de faible poids moléculaire (par exemple, GluadinR Kera-P LM) avec un rapport massique approprié a montré un fort effet synergique sur les propriétés de conditionnement des cheveux. Il pourrait fournir une référence significative pour le développement de produits capillaires sans silicone avec plus d'avantages.

Choroidal vascular changes in silicone oil-filled eyes after vitrectomy for rhegmatogenous retinal detachments.

INTRODUCTION: The tamponade of silicone oil (SO) can affect both the structure and blood flow of the retina. However, there are few studies on the effect of SO tamponade on choroidal blood flow. Our study aimed to compare the effects of SO tamponade on the choroidal vascular index (CVI) and choroidal thickness (CT) in patients with unilateral rhegmatogenous retinal detachment (RRD) with operated eyes and fellow healthy eyes. METHODS: We retrospectively collected demographic and clinical data from 36 patients who underwent 23G pars plana vitrectomy and SO tamponade for unilateral complicated RRD. Enhanced depth imaging-optical coherence tomography (EDI-OCT) scans were performed both within 1 week before SO removal and at the last follow-up visit after SO removal. Using ImageJ software, images were binarized to segment the total choroidal area, luminal area, and stromal area, respectively. The CVI was calculated as CVI=(luminal area)/(total choroidal area), and CT was also evaluated. RESULTS: During SO tamponade, the CVI and luminal area in operated eyes were significantly lower compared to fellow eyes (57.616 ± 0.030 vs. 60.042 ± 0.019, P < 0.0001; 0.909 [0.694; 1.185] vs. 1.091 [0.785; 1.296], P = 0.007). Even after SO removal, the CVI remained lower in operated eyes than in fellow eyes (59.530 ± 0.018 vs. 60.319 ± 0.020, P = 0.031). Both CVI and luminal area were lower in operated eyes before SO removal than after SO removal (57.616 ± 0.030 vs. 59.530 ± 0.018, P = 0.0003; 0.909 [0.694; 1.185] vs. 0.994 [0.712; 1.348], P = 0.028). The duration of SO tamponade was positively correlated with the difference in CVI between fellow eyes and operated eyes during SO tamponade (P = 0.035). Total choroidal area, stromal area, and CT did not differ significantly between fellow eyes and operated eyes or between pre- and post-SO removal. CONCLUSIONS: SO tamponade reduces CVI and decreases choroidal blood circulation in patients with retinal detachments required vitrectomy combined with SO tamponade. The longer the SO tamponade time, the more CVI reduction. In future work, we will aim to reduce these side effects by shortening the duration of silicone oil filling.

Effect of the Presence of Silicone Oil in the Anterior Chamber After Complicated Retinal Detachment Surgery on Corneal Morphology by In Vivo Confocal Microscopy.

PURPOSE: This study evaluated the corneal endothelium, stromal keratocytes, subbasal nerve number and density in patients with silicone oil transferred to the anterior camera after pseudophakic complicated retinal detachment surgery by in vivo laser scanning confocal microscopy (IVLSCM). METHODS: Sequential measurements were made by IVLSCM between 3-6 months after surgery in two groups of patients: a) with silicon oil migration (Group 1) and without silicone oil migration (Group 2). RESULTS: A total of 63 cases (Group 1: 32 and Group 2: 31) were examined. The mean ages of patients were 65 ± 12 and 61 ± 11 and M/F ratio was 18/14 and 17/14, respectively. Mean intraocular pressures were 16.60 ± 4.60 and 15.75 ± 5.70 mm Hg, respectively. Changes were detected by IVLSCM mostly on the superior part of the cornea. A significant decrease in endothelial cell density and the number was detected in group 1 (2072 ± 116.2 cells/mm2 vs 2752 ± 512.3 cells/mm2; p < 0.001). Significant increases in posterior keratocyte density and stromal hyperreflective deposits were observed in group 1 (887 ± 45.8 cells/mm2 vs 725 ± 65.8 cells/mm2; p < 0.001). A significant negative correlation was observed between the size of stromal deposits and endothelial cell density (r=-0.758; p < 0.001). The number and density of corneal subbasal nerves were significantly lower in group 1 (1.8 ± 0.8 and 4.8 ± 1.2 vs 420 ± 101 and 701 ± 112 µm/square; p < 0.001). CONCLUSION: IVLSCM is a useful tool for the early detection of corneal abnormalities caused by silicone oil injection. This study verified silicone oil's detrimental effect on the corneal endothelium and revealed stromal changes in the anterior chamber, which we believe can be also been associated with the presence of silicone oil.

Nitric Oxide-Releasing Silicone Oil with Tunable Payload for Antibacterial Applications.

Bacterial infections are a hurdle to the application of medical devices, and in the United States alone, more than one million infection cases are reported annually from indwelling medical devices. Infections not only affect the function of medical devices but also risk the lives and health of patients. Nitric oxide (NO) has been used as an antibacterial therapy that kills bacteria without causing resistance and provides many therapeutic effects such as anti-inflammation, antithrombosis, and angiogenesis. Silicone oils have been widely utilized in manufacturing consumer goods, healthcare products, and medical products. Specifically, liquid silicone oils are used as a medical lubricant that creates lubricated interfaces between medical devices and the exterior physiological environment to improve the performance of medical devices. Herein, we report the first primary S-nitrosothiol-based NO-releasing silicone oil (RSNO-Si) that exhibits proactive antibacterial effects. S-nitrosothiol silicone oils (RSNO-Si) were synthesized and the NO payloads ranged from 34.0 to 603.9 µM. The increased NO payload induced higher-viscosity RSNO-Si oils, as RSNO0.1-Si, RSNO0.5-Si, and RSNO1-Si had viscosities of 12.8 ± 0.1 cP, 32.0 ± 0.2 cP, and 35.1 ± 0.3 cP, respectively. RSNO-Si-SR interfaces were fabricated by infusing silicone rubber (SR) in RSNO-Si oil, and the resulting RSNO-Si-SR disks demonstrated NO release without NO donor leaching. RSNO0.1-Si-SR, RSNO0.5-Si-SR, and RSNO1-Si-SR exhibited maximum NO flux at 0.8, 6.5, and 21.5 × 10 -10 mol cm-2 min-1 in 24 h, respectively. RSNO-Si-SR disks also demonstrated 97.45, 95.40, and 96.08% of inhibition against S. aureus in a 4 h bacterial adhesion assay. Considering the easy synthesis, simple fabrication of non-leaching NO-releasing interfaces, tunable payloads, NO flux levels, and antimicrobial effects, RSNO-Si oils exhibited their potential use as platform chemicals for creating antimicrobial medical device surfaces and other antibacterial materials.

Longitudinal evaluation of retinal thickness and OCTA parameters before and following silicone oil removal in eyes with macula-on and macula-off retinal detachments.

BACKGROUND: To investigate the longitudinal retinal vascular and structural alterations by using OCTA following successful repair of retinal detachment (RD) by using silicone oil (SO) endotamponade. METHODS: A prospective cohort study was performed on 24 eyes of 24 subjects; 17 of them with macula-off and seven with macula-on RD. At least four OCTA scans were generated for each study eye; two before and two after SO removal (SOR). At each session, retinal thickness (RT), vascular density (VD) in the superficial (SCP) and deep capillary plexuses (DCP) and foveal avascular zone(FAZ) size were measured within the fovea, parafovea and whole macular image. The changes in repeated measures of the same parameters especially before and after SOR were performed and compared within macula-on and macula-off groups and between fellow eyes. RESULTS: "In the macula-off eyes, RT measurements within the whole macula, fovea and parafovea reduced as compared with their fellow eyes(p < 0.0001, p = 0.001 and p < 0.0001, respectively) and did not improve after SOR. Additionally, all of the whole macular, foveal, and parafoveal VD measurements at SCP and foveal VD at DCP were less than their fellow eyes after SOR (p = 0.026, p = 0.023 p = 0.026, and p = 0.002, respectively). In macula-on eyes, RT measurements decreased within the parafovea and whole macular area before SOR (p = 0.018 and p = 0.011, respectively) but improved after SOR. Also, VD measurements did not change during follow-up and were not statistically different than their fellow eyes (p > 0.05). FAZ enlargement was found in eyes with macular-off RD after SOR, whereas it was not observed with macular-on RD (p = 0.038and p = 0.237, respectively). CONCLUSIONS: Treatment of macula-off RD with SO tamponade has been associated with vascular retinal abnormalities which did not improve following SOR. On the contrary, successful treatment of RD with SO tamponade in macula-on eyes VD measurements of SCP and DCP were not statistically different than their fellow eyes.

Status of corneal endothelial cells in the presence of silicone oil in the anterior chamber.

To evaluate corneal endothelium damage with silicone oil (SO) presence in the anterior chamber after pars plana vitrectomy. We investigated the medical records of consecutive 54 eyes of 53 patients undergoing SO removal after pars plana vitrectomy with SO tamponade at Saitama Medical Center, Jichi Medical University, Japan. We recorded SO tamponade retention period, anterior chamber SO with gonioscope, area of SO attachment to the corneal endothelium before SO removal surgery, and the lens status. We then retrospectively investigated the correlation between SO presence in the anterior chamber and the decrease rate of corneal endothelial cell (CEC) density during SO tamponade. The average decrease rate of CEC density was 7.6 (0-38.1) %. The correlation between SO tamponade retention period and decrease rate of CEC density was high (p = 0.0001). However, there was no correlation between anterior chamber SO under gonioscope, SO attaching area, and lens status with the decrease rate of CEC density (p = 0.11, p = 0.93, p = 0.16). No correlation was observed between CEC loss and the existence of anterior chamber SO, although CEC decrease rate was relatively high after a long SO tamponade period. These findings suggest that SO presence in the anterior chamber may not directly injure CEC.

Off-label use of plastic syringes with silicone oil for intravenous infusion bags of antibodies.

The formation of particulates in post-manufacture biopharmaceuticals continues to be a major concern in medical treatment. This study was designed to evaluate the content of micro-sized particles using flow imaging of antibodies in intravenous infusion bags. Intravenous immunoglobulin (IVIG) and Avastin® were selected as model drugs and plastic syringes with and without silicone oil (SO) were used to transfer the drugs into the bags (0.9% saline or 5% dextrose). Antibodies exposed to SO had significantly increased levels of microparticles in both diluents, suggesting SO accelerates particle formation, especially at a higher antibody concentration. Even before the drop stress, their count exceeded the USP guideline. Dropping the bags in the presence of SO produced larger microparticles. Meanwhile, air bubbles were retained longer in saline suggesting more protein film formation on its air-water interface. Overall, both drugs were conformationally stable and produced less particles in dextrose than in saline.

Transient Macular Thinning during the Use of Heavy Silicone Oil, Densiron 68.

BACKGROUND: To evaluate the effect of short-term Densiron tamponade on macular thickness. METHODS: Retrospective case series. Data were collected from charts of patients who received short-term (less than 90 days) Densiron tamponade. The OCT parameters were compared between Densiron in situ and after Densiron removal and to the fellow eye. RESULTS: Twenty eyes were included in the analysis. Although there was a trend toward thinner CRT with Densiron in situ in situ the operated eye when compared to the fellow eye (248 and 264 microns, respectively, p = .066), this difference disappeared after DR. At the final OCT there was a statistically significant recovery in the CRT (from 248 to 277 microns, P = .001) and no statistical difference between operated and the fellow eye (p = .265) with no evidence of ERM or CME. CONCLUSIONS: We found transient macular thinning that resolved after Densiron removal with no evidence of long-term macular thinning in eyes treated with Densiron tamponade for retinal detachment.

COMPARING VITRECTOMY, SILICONE OIL ENDOTAMPONADE WITH/WITHOUT CYCLOPEXY TO TREAT CYCLODIALYSIS CLEFTS WITH SEVERE OCULAR TRAUMA.

PURPOSE: Comparing the anatomical and functional outcomes of vitrectomy, silicone oil endotamponade without cyclopexy (VEWOC) and with cyclopexy (VEWC) in patients with traumatic cyclodialysis clefts and severe ocular comorbidities. METHODS: A total of 55 patients (55 eyes) with traumatic cyclodialysis clefts were divided into VEWOC and VEWC groups according to the surgery undergone. Besides the cyclodialysis clefts, all study eyes had one or more additional conditions caused by severe ocular trauma: cataract, lens dislocation, vitreous hemorrhage, retinal detachment, choroidal detachment, maculopathy, suprachoroidal hemorrhage, subretinal hemorrhage, or proliferative vitreoretinopathy. The minimum postoperative follow-up period for all patients was six months. The main measures of outcome were rate of successful anatomical repair, intraocular pressure, and best-corrected visual acuity. RESULTS: Both the VEWOC group (33 eyes) and the VEWC group (22 eyes) showed significant improvement in postoperative best-corrected visual acuity and intraocular pressure at the final follow-up. The groups had no significant differences in terms of anatomical success rates (VEWOC 29/33 vs. VEWC 20/22, P = 1.000), final best-corrected visual acuity (VEWOC 1.60 ± 0.76 [median Snellen acuity: counting fingers, range: light perception to 20/20] vs. VEWC 1.46 ± 0.66 [median Snellen acuity: 20/800, range: light perception to 20/32], P = 0.485), and final intraocular pressure (VEWOC 13.40 [8.20-17.80] vs. VEWC 11.40 [6.65-14.00] mmHg, P = 0.311). However, the intraocular pressure on postoperative Day 1 was significantly different between the groups (VEWOC 10.40 [6.40-14.60] vs. VEWC 6.40 [4.70-7.98] mmHg, P = 0.002). CONCLUSION: This study showed that both surgical approaches were equally effective in treating cyclodialysis clefts secondary to severe ocular trauma. Therefore, it may be unnecessary to perform cyclopexy in addition to the vitrectomy procedure in such cases.

SIX MONTHS PRIMARY SUCCESS RATE FOR RETINAL DETACHMENT BETWEEN VITRECTOMY AND SCLERAL BUCKLING.

PURPOSE: To compare clinical outcomes between pars plana vitrectomy (PPV), scleral buckling (SB), and PPV+SB for rhegmatogenous retinal detachment in the Japan-RD Registry. METHODS: This is a nation-wide, multicenter, observational study based on the registry data between 2016 and 2017. The failure levels were defined as Level 1 (a failure of retinal detachment repair), Level 2 (remaining silicone oil), and Level 3 (multiple surgeries to achieve reattachment). We compared cases treated by SB or PPV in the subgroup of simple rhegmatogenous retinal detachment using multivariate Cox proportional hazard models. RESULTS: A total of 2,775 cases were included. Overall, 6 months any levels of failure in total, SB, PPV, and PPV+SB were 9.2% (n = 256), 6.9% (n = 48), 8.2% (n = 157), and 21.3% (n = 51), respectively. Poor visual acuity at baseline in SB and inferior rhegmatogenous retinal detachment and larger retinal tear in PPV were associated with a higher risk of failure. Pars plana vitrectomy was associated with a higher chance of achieving primary success in cases with simple RRD, especially for cases with superior RRD (adjusted hazard ratio 3.61, 95% confidence interval 2.22-5.94, P < 0.001). CONCLUSION: In this nationwide study, surgical anatomic outcomes were equally successful in either SB or PPV. There were different baseline characteristics associated with primary success between SB and PPV.

VISUAL IMPAIRMENT AND MACULAR VASCULAR REMODELING SECONDARY TO RETROGRADE MACULOPATHY IN RETINAL DETACHMENT TREATED WITH SILICON OIL TAMPONADE.

PURPOSE: To assess the frequency of macular cysts (MCs) in retinal detachment treated with silicone oil and evaluate their impact on visual acuity and macular vascularization using optical coherence tomography-angiography. METHODS: Forty-three eyes of 41 patients treated with silicone oil for retinal detachment were retrospectively studied. Best-corrected visual acuity and 6- × 6-mm optical coherence tomography-angiography examination at least 3 months after silicone oil removal were reviewed. In eyes with MCs, cyst area was measured on the en face optical coherence tomography-angiography image using ImageJ. Density of superficial capillary plexus and area of superficial foveal avascular zone were generated by the optical coherence tomography-angiography. Density of deep capillary plexus and deep foveal avascular zone area were measured using ImageJ. RESULTS: Twenty-five eyes (58%) presented with MCs. Cysts were exclusively located in the inner nuclear layer in 60% of cases. Mean best-corrected visual acuity in the MC group was lower than that of the non-MC group (P = 0.012). Macular cyst area negatively correlated with best-corrected visual acuity (P = 0.0201). Density of superficial capillary plexus was higher in the MC group (P < 0.0001), whereas area of superficial foveal avascular zone was lower (P < 0.0001). Macular cyst area negatively correlated with density of deep capillary plexus (P < 0.001). CONCLUSION: The incidence of INL-MCs after silicone oil removal is high. These are associated with impaired vision and macular vascular remodeling. We highlight their similarity with the "retrograde maculopathy" phenomenon.

SILICONE OIL VERSUS PERFLUOROPROPANE GAS TAMPONADE DURING VITRECTOMY FOR TRACTIONAL RETINAL DETACHMENT OR FIBROUS PROLIFERATION: A Randomized Clinical Trial.

PURPOSE: To compare vitreous substitution with silicone oil to perfluoropropane gas in proliferative diabetic retinopathy subjects undergoing pars plana vitrectomy (PPV) for the treatment of tractional retinal detachment or extensive fibrous proliferation. DESIGN: Randomized clinical trial. METHODS: Three hundred and two proliferative diabetic retinopathy subjects with tractional retinal detachment or extensive fibrous proliferation requiring PPV were enrolled into the trial. Subjects were prospectively randomized into one of two vitreous substitution groups during PPV: Group A subjects underwent 1,000 centistoke silicone oil tamponade, whereas Group B subjects underwent 14% to 16% silicone oil to perfluoropropane gas tamponade. The principal outcome was the best-corrected visual acuity at 6-month follow-up. Secondary outcomes were postoperative complications and unplanned PPV during the 6-month trial interval. RESULTS: Two hundred and fifty-eight subjects were randomized to receive a vitreous substitute and completed 6-month follow-up. Group B had better best-corrected visual acuity, more subjects ending up with 0.4 logarithm of the minimum angle of resolution (20/50) or better visual acuity, and more subjects ending up with 1 logarithm of the minimum angle of resolution (20/200) or better visual acuity at 6 months compared with Group A (P < 0.001, P = 0.02, P < 0.001, respectively). There were no significant differences in baseline characteristics, intraoperative or postoperative complications, or incidence of unplanned PPV between groups. CONCLUSION: This trial demonstrated that vitreous substitution with silicone oil to perfluoropropane gas resulted in better visual acuity at 6 months compared with silicone oil tamponade in proliferative diabetic retinopathy patients undergoing PPV for tractional retinal detachment or extensive fibrous proliferation. Surgeons should consider silicone oil to perfluoropropane gas tamponade as the first-line vitreous substitute in this patient population.

Making medical devices safer: impact of plastic and silicone oil on microbial biofilm formation.

BACKGROUND: Medical devices face the challenge of microbial biofilm attached to the surface. Ultimately, this may jeopardize the function of the device and increase the patient's risk of infection. However, reliable methods to prevent biofilm are lacking. AIM: To investigate the effect of silicone oil-coated polypropylene plastic, used in a new automatic urinometer, on biofilm formation; furthermore, to explore the impact of silicone oil viscosity and compare polypropylene with polystyrene, another common medical plastic. METHODS: Common pathogens, including extended-spectrum beta lactamase (ESBL) -producing and multi-drug-resistant bacteria, as well as Candida albicans, were investigated. Isogenic Escherichia coli strains deficient in the important biofilm forming factors curli, cellulose and type 1 fimbriae (fim D) were used to determine the possible mode of action by silicone oil. Clear flat-bottomed polypropylene or polystyrene wells were pretreated with either low- or medium-viscosity silicone oil and microbes were added. After 72 h, biofilm formation was quantified using crystal violet assay. FINDINGS: Silicone oil-coated polypropylene plastic surfaces, regardless of the oil viscosity, significantly inhibited biofilm formation of all tested Gram-negative and Gram-positive bacteria, including ESBL-producing and multi-drug resistant strains, as well as C. albicans. Silicone oil did not affect bacterial or candida growth and curli fimbriae were found to be the main target of silicone oil. Polypropylene plastic itself without oil had a better effect in preventing biofilm formation than polystyrene. CONCLUSION: These findings suggest a new strategy to decrease microbial biofilm formation, which may reduce hospital-acquired infections and prevent dysfunction of medical devices.

The effect of silicone oil presence time on macular and choroidal thickness with macula-off rhegmatogenous retinal detachment.

OBJECTIVE: To investigate the effects of silicone oil (SiO) on macular thickness (MT) and subfoveal choroidal thickness (SFCT) in patients with macula-off rhegmatogenous retinal detachment (RRD) undergoing pars plana vitrectomy (PPV). MATERIAL AND METHODS: In this prospective study, 70 eyes of 70 patients who received SiO tamponade for the treatment of macula-off RRD were treated with PPV and a 5000-cSt SiO endotamponade followed by subsequent SiO removal. MT and SFCT were measured 1 day before and 3 months after SiO removal using spectral-domain optical tomography (SD-OCT) and enhanced depth imaging optical tomography (EDI-OCT). The patients were divided into 3 groups according to the length of time that the SiO was present: group 1 (3-6 months), group 2 (6-9 months), and group 3 (9-18 months). RESULTS: A total of 70 eyes of 70 patients with a mean age of 57.22±9.83 years (range: 30 years to 75 years) were included in the SiO (5000-cSt) study. SiO was extracted after a mean duration of 8.67±5.33 months (range, 3-18 months) after PPV. In the 1st group, BCVA increased from 1.83±0.32 log MAR before PPV to 0.85±0.41 log MAR at 3 months after silicone removal (P<0.001). In the 2nd group, BCVA increased from 1.76±0.38 log MAR before PPV to 0.86±0.48 log MAR at 3 months after silicone removal (P<0.001). In the 3rd group, BCVA increased from 1.89±0.28 log MAR before PPV to 1.08±0.63 log MAR at 3 months after SiO removal (P=0.001). There was no statistically significant change in MT in the difference values of each group. As the length of SiO presence in the eye increased, significant thinning was observed on measurement of SFCT. Differences in the SFCT values were -14.91µm, -18.76µm, and -51.50µm in groups 1, 2, and 3 respectively (P=0.004). CONCLUSIONS: A significant decrease in macular and choroidal thicknesses after SiO removal was observed. Presence of SiO endotamponade for 9 months was associated with subfoveal choroidal thinning and decreased final visual acuity in eyes undergoing RRD surgery. SD-OCT and EDI-OCT may be recommended for the treatment and follow-up of patients with complications caused by the use of SiO tamponade.

Comparison of Long-Term Automated Retinal Layer Segmentation Analysis of the Macula between Silicone Oil and Gas Tamponade after Vitrectomy for Rhegmatogenous Retinal Detachment.

PURPOSE: To identify long-term changes in individual retinal layer thickness using automated retinal layer segmentation analysis on high-resolution spectral-domain optical coherence tomography (SD-OCT) scans of eyes with macula-off rhegmatogenous retinal detachment (RRD) treated with vitreoretinal surgery (VRS) and gas or silicone oil tamponade and having single-operation success. METHODS: A total of 58 patients operated on by VRS for RRD and followed up for 12 months were imaged by SD-OCT. The patients with retinal diseases such as an epiretinal membrane or cystic macular edema in the operated and fellow eyes were excluded. The thicknesses of the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor layer, and retinal pigment epithelium were compared to those of the fellow eyes after the 12-month follow-up. Thickness changes in individual layers were quantitatively analyzed in the operated and fellow eyes and correlated with the type of tamponade used in the surgery. RESULTS: Spectralis OCT automated segmentation software was used for the retinal layer analysis. There were 22 females and 36 males. Their mean age was 60.7 ± 11.2 years. The mean central macular thickness was 214.3 ± 29.5 µm in the operated and 229.7 ± 21.7 µm in the fellow eyes (p = 0.008). There was a statistically significant difference between the operated and the healthy fellow eyes in the following layers: the RNFL (p = 0.017), GCL (p = 0.02), INL (p = 0.005), and ONL (p = 0.008) in the central foveal area; the RNFL (p < 0.001), INL (p = 0.017), and ONL (p = 0.022) in the perifoveal ring; and the RNFL (p < 0.001), IPL (p = 0.042), INL (p = 0.001), and OPL (p = 0.001) in the peripheral ring. The logMAR best corrected visual acuities were 2.51 ± 0.68 and 2.69 ± 0.62 at baseline and 0.60 ± 0.38 and 0.50 ± 0.38 at month 12 in the silicone oil tamponade (n = 28) and the gas tamponade (n = 30) group (p = 0.52 and p = 0.21, respectively). The foveal GCL, OPL, and ONL and the perifoveal GCL and IPL were statistically significantly thinner in the silicone oil tamponade group (p = 0.01, p = 0.046, p = 0.024, p = 0.006, and p = 0.011, respectively). CONCLUSIONS: Significant changes were observed in the retinal layers after VRS for RRD. Individual retinal layers seem to be affected 1 year after VRS for RRD. The type of tamponade can influence the thickness of the retinal layers. The thickness of the retinal layers was significantly preserved in eyes treated with gas tamponade when compared to those treated with silicone oil tamponade in the long term. Further studies are needed to validate our results.

SILICONE OIL TAMPONADE EFFECT ON MACULAR LAYER THICKNESS AND VISUAL ACUITY.

PURPOSE: To evaluate the influence of silicone oil (SO) tamponade on retinal layers thickness and visual acuity in patients who underwent pars plana vitrectomy for rhegmatogenous retinal detachment. METHODS: This is a retrospective case series of consecutive patients who underwent pars plana vitrectomy for rhegmatogenous retinal detachment with SO tamponade. Visual acuity and central macular thickness were measured with SO and at least a month after SO removal (SOR). Patients with insufficient or poor-quality images or macular pathologies such as macular edema or epiretinal membranes were excluded. RESULTS: Forty-one patients with an average age of 56.1 ± 15.2 years were included, and 54% presented with fovea ON. Average tamponade duration was 151 ± 54 days. Central macular thickness of the operated eye increased from 249 ± 50 µm before to 279 ± 48 µm after SOR (P < 0.001), compared with 281 ± 21 µm of the fellow eye (P < 0.001). A mean change of 26 µm was found in the internal layers (P < 0.001). Visual acuity improved from 0.85 ± 0.97 logarithm of the minimal angle of resolution (logMAR; Snellen 20/140) with SO tamponade to 0.34 ± 0.28 logMAR (Snellen 20/43) after SOR (P < 0.001). For patients with fovea ON and without significant cataract, visual acuity was 0.19 ± 0.16 logMAR (Snellen 20/30) at presentation, 0.59 ± 0.41 logMAR (Snellen 20/80) with SO (P = 0.005), and 0.18 ± 0.15 logMAR (Snellen 20/30) after SOR (P = 0.003). CONCLUSION: Silicone oil tamponade causes a transient decrease in central macular thickness, mainly in the inner layers. After SOR, central macular thickness resembles to the fellow eyes. The mechanism for this effect is unclear, but apparently has no influence on final visual acuity.

Silicone Oil Tamponade in Rhegmatogenous Retinal Detachment: Functional and Morphological Results.

Purpose: To evaluate the functional and morphological outcomes of patients with SO tamponade due to primary rhegmatogenous retinal detachment (primRD) and recurrent rhegmatogenous detachment (recRD).Methods: Seventy-five eyes were enrolled in this prospective study between January 2009 and December 2016. Patients with primRD and recRD were evaluated in a complete ophthalmic examination including best-corrected visual acuity (BCVA) and OCT before and after silicone oil removal (SOR).Results: The primRD group comprised 35 eyes and the recRD group 40 eyes with a duration of SO tamponade of 9 ± 4/12 ± 11 months in the primRD/recRD groups (p = .088). The preoperative OCT revealed a high rate of morphological changes such as ERM (primRD: 24%; recRD: 69%) and CME (primRD: 10%; recRD: 55%) in the recRD compared with the primRD group (ERM: p = .18; CME: p = .04). No such difference was observed postoperatively. Disruption of the ellipsoid zone (EZ) was similar in both groups (primRD: 52%; recRD: 72%) before SOR and was restored in 66%/58% (primRD/recRD) after SOR. No difference was found regarding pre- and postoperative VA (0.91 ± 0.54/0.90 ± 0.54logMAR primRD/recRD preoperative; 0.76 ± 0.56/0.71 ± 0.53logMAR primRD/recRD at the last follow-up; p = .96/p = .70). EZ integrity (0.43 ± 0.31logMAR) was associated with better functional results than an interrupted EZ (0.86 ± 0.43logMAR; p < .001). A significant positive correlation of the duration of SO tamponade and the final VA was found in the primRD (r = 0.396, p = .02) whereas none in the recRD group (r = 0.196; p = .31).Conclusion: Morphological changes including ERM and CME were more pronounced in the recRD group, but only before SOR. Interestingly, the pre- and postoperative BCVA were similar in both groups with EZ integrity being a factor of good functional outcome. The duration of SO tamponade had a statistically significant negative impact on the postoperative VA in the primary detachments.

Performance assessment of gas-phase toluene removal in one- and two-liquid phase biotrickling filters using artificial neural networks.

The main aim of this work is to study gas-phase toluene removal in one- and two-liquid phase biotrickling filters (O/TLP-BTF) and model the BTF performance using artificial neural networks (ANNs). The TLP-BTF was operated for 60 d in the presence of silicone oil at empty bed residence times (EBRTs) of 120, 60, and 45 s, respectively, and toluene concentrations in the range of 0.9-3.1 g m-3. A t-test analysis indicated that increasing the silicone oil volume ratio from 5 to 10% v/v, did not significantly improve the TLP-BTF performance (p-value = 0.65 > 0.05). The results from ANN modeling showed that toluene removal was more negatively affected by the inlet concentration (casual index, CI = -5.63) due to the kinetic limitation. The CI values for inlet concentration (+4.01) and liquid trickling rate (-2.45) indicated that the diffusion-limited regime controlled the removal process in the OLP-BTF.