Emulsified Silicone Oil Droplets Research Articles

Anterior segment optical coherence tomography for the detection of silicone oil emulsification on the iris surface.

To investigate the presence of silicone oil (SO)-emulsification on the anterior iris surface with anterior segment optical coherence tomography (AS-OCT). In this single-center cross-sectional study, vitrectomized eyes with SO tamponade that underwent AS-OCT imaging and gonioscopy examination during the postoperative follow-up visits, were reviewed. 45 eyes of 42 consecutive patients were included. In 35.6% of the eyes (n = 16) emulsified SO droplets were detected in the anterior chamber (AC) angle by gonioscopy and in 55.6% (n = 25) on the anterior iris surface by AS-OCT imaging. The presence of SO emulsifications in the AC-angle correlated with the presence of SO emulsifications on the anterior iris surface (OR = 13.4, 95% CI [2.179-82.130]; p = 0.005). The accuracy of the AS-OCT predicting the presence of SO in the AC-angle was 71.0% and the sensitivity was 87.5%. No significant association between SO droplets in the AC and other clinical parameters including endotamponade-duration or type of silicone oil were found. The presence of emulsified SO droplets on the anterior iris surface detected by AS-OCT was significantly correlated to postoperative IOP rise (p = 0.027). AS-OCT is a suitable method for the detection of SO on the anterior iris surface. SO droplets on the iris surface correlate with elevated postoperative IOP and with the presence of SO in the AC detected by gonioscopy, therefore AS-OCT might be used as a screening method for the detection of SO migration into the AC. Institutional Review Board of the Hamburg Medical Chamber (Ethik-Kommission der Ärztekammer Hamburg): 2023-300372-WF.

Silicone oil emulsification: A literature review and role of widefield imaging and ultra-widefield imaging with navigated central and peripheral optical coherence tomography technology.

Silicone oil (SO) emulsification is a significant concern in vitreoretinal surgery, leading to various complications. Despite the high prevalence of SO emulsification within the eye, there is currently no standardized method for its early detection. The recent introduction of widefield (WF) imaging and ultra-WF (UWF) imaging with navigated central and peripheral optical coherence tomography (OCT) techniques have shown promising results in providing high-resolution images of the peripheral vitreous, vitreoretinal interface, retina, and choroid. This enhanced visualization capability enables the early identification of emulsified SO droplets, facilitating a proactive therapeutic approach, and mitigating associated adverse events. This comprehensive literature review aims to provide an updated overview of the topic, focusing on the role of WFimaging and UWF imaging and navigated central and peripheral swept-source OCT (SS-OCT) in the early detection and management of SO emulsification. The review discusses the current understanding of SO emulsification, its associated complications, and the limitations of existing detection methods. In addition, it highlights the potential of WF and UWF imaging and peripheral OCT as advanced imaging modalities for improved visualization of SO emulsification. This review serves as a valuable resource for clinicians and researchers, providing insights into the latest advancements in the field of vitreoretinal surgery and the promising role of WF imaging and UWF imaging and navigated central and peripheral SS-OCT in the management of SO.

Sweeping technique for the removal of emulsified silicone oil droplets from the anterior surface of the iris using an ophthalmic absorption sponge.

Silicone oil (SO) tamponade is frequently used in complex vitreoretinal surgeries, and SO migration into the anterior chamber can lead to complications such as glaucoma and corneal decompensation. A new technique is described for the efficient removal of emulsified SO droplets, which can adhere strongly to the anterior surface of the iris. The tip of an ophthalmic absorption sponge was cut to an approximately 1x1 mm size. Using forceps, the sponge was inserted through a 25-gauge trocar, then through a corneal paracentesis, to gently scrape the surface of the iris to dislodge the adherent SO droplets, which were subsequently aspirated. This technique efficiently and effectively dislodged and mobilized most emulsified SO droplets, thereby allowing removal via aspiration using a vitrector. Two months after surgery, the retina remained attached, the intraocular pressure decreased from 18 mmHg to 15 mmHg, and there were no visible SO droplets in the anterior chamber. The sweeping technique is a safe and efficient method to dislodge, mobilize and aspirate emulsified SO droplets that are adherent to the anterior surface of the iris, thereby decreasing the risk of future SO-related complications.

Intracameral vent and flush technique for silicone oil blockade in Ahmed glaucoma valve.

The presence of emulsified silicone oil in the eye can lead to many complications, glaucoma being one of the most common. Adequate IOP control is difficult to achieve with medical management alone; surgical intervention is often required. Glaucoma drainage device implantation is often the preferred line of surgical intervention in such cases due to trabeculectomy failure from emulsified silicone oil droplets and associated conjunctival scarring. However, the silicone tube of Ahmed glaucoma valve (AGV) may attract the silicone oil droplets, causing blockade of the tube with persistent raised IOP postoperatively. We report one such case where post-AGV silicone oil tube occlusion was treated with semi-conservative surgical management instead of revising the entire surgery or implantation of another drainage device. Our surgical technique of intracameral “vent and flush” offers rapid and effective IOP control in such cases. Postoperatively, normal IOP was achieved. Patency of tube continued to be maintained along with normalization of IOP on subsequent follow-ups.

Incomplete posterior vitreous detachment despite vitrectomy with silicone oil tamponade

The fundamental step of a successful vitrectomy is posterior vitreous detachment induction; however, incomplete induction sometimes occurs. It may not be well seen barely by ophthalmoscopy examination, but emulsified silicone oil droplets act as the agent highlighting out the two natural retro-hyaloid spaces. The emulsified silicone oil droplets float according to gravity, but were entrapped over the pre-optic disc and the pre-macular bursa, giving the funny double inverse hypopyon-like pattern over the posterior segment.

Comparison of Repeated Fluid-Air Exchange and Passive Drainage for Removing Residual Emulsified Silicone Oil Droplets.

Purpose To compare the efficacy of passive drainage (PD) and repeated fluid-air (FA) exchange for removing emulsified silicone oil (SO) droplets. Methods Twenty rhegmatogenous retinal detachment (RRD) patients who underwent primary pars plana vitrectomy (PPV) with SO tamponade were randomly and evenly divided into two groups for PD and FA exchange. Once the bulk of SO was removed, the first 2 mL of the washout fluid was collected, and then, another 2 mL of the washout fluid was collected after PD or FA exchange. The size and number of SO droplets in the washout fluid were measured using a Coulter counter (Multisizer 3, Beckman Coulter, Indianapolis, IN, USA). The efficiencies of FA exchange and PD for removing emulsified SO were compared. Results The number of SO droplets decreased significantly after FA exchange and PD. The decrease in the number of droplets was statistically significant for larger droplets (>4 µm) with PD and for all droplet sizes with FA exchange. The decrease in the number of SO droplets of <4 μm was significantly greater with FA exchange than with PD. However, at the end of the procedure, the overall number and size distribution of SO droplets were similar for both procedures. Conclusions PD and FA exchange reduced the number of residual emulsified SO droplets after SO tamponade efficiently. FA exchange may have some advantages over PD in removing small droplets.

Silicone Oil Emulsification after Vitrectomy for Rhegmatogenous Retinal Detachment.

Purpose To investigate the characteristics of silicone oil (SO) emulsification after vitrectomy for rhegmatogenous retinal detachment and their possible correlations with clinical factors. Methods The first 2 mL of washing out fluid after SO removal was collected, and used for the measurement of the size and number of SO droplets using a Multisizer® 3 Coulter counter (Beckman Coulter, USA). The correlations between SO droplets and clinical factors were analyzed. Results A total of 38 patients (23 males, 15 females) who underwent primary PPV with SO injection for RRD and whose retina stayed attached for ≥3 months after SO removal were included in the study. The average number of oil droplets was 1.96 × 106 ± 3.95 × 106/mL (range 0.17 × 106 to 21.71 × 106/ml), and 80.8% (range 64.23%–99.07%) of the droplets were 1-2 μm in diameter. The total number of emulsified SO droplets was not correlated with any clinical factor (all P > 0.05). When the emulsified SO droplets were divided into groups by their diameter, multiple linear regression revealed that age was negatively correlated with the numbers of 5–7-μm in diameter. The total number of emulsified SO droplets was not correlated with any clinical factor (all μm in diameter. The total number of emulsified SO droplets was not correlated with any clinical factor (all P > 0.05). When the emulsified SO droplets were divided into groups by their diameter, multiple linear regression revealed that age was negatively correlated with the numbers of 5–7-μm in diameter. The total number of emulsified SO droplets was not correlated with any clinical factor (all μm in diameter. The total number of emulsified SO droplets was not correlated with any clinical factor (all P > 0.05). When the emulsified SO droplets were divided into groups by their diameter, multiple linear regression revealed that age was negatively correlated with the numbers of 5–7-Conclusion Using a Multisizer® Coulter counter, we successfully determined the number and size of SO droplets after emulsification. We found that the number of 5–12-μm-diameter droplets was higher in younger-age patients and was higher in patients using antiglaucoma eyedrops.μm in diameter. The total number of emulsified SO droplets was not correlated with any clinical factor (all

Amphiphilic additives in silicone oil tamponade and emulsification: an eye-on-a-chip study.

Recently, chemically modified silicone oil has been demonstrated as a reservoir for sustained release of intraocular drugs, many of which might be amphiphilic in nature. In this work, we study the effect of amphiphilic additives in silicone oil on emulsification under eye-like movements. Three silicone-oil-soluble surfactants, namely DC749, MQ1640 and FZ2233, were used as model amphiphilic additives. The change of viscosity was measured by a rheometer in the cone-and-plate geometry. The interfacial tension (IFT) between silicone oil and model aqueous phase was measured by pendant drop tensiometry. Emulsification of silicone oil was induced by simulated saccadic eye movements on a cell-coated eye-on-a-chip platform for 4 days. The number of emulsified silicone oil droplets observed in the aqueous phase was assessed daily by optical microscopy. Significantly more emulsified droplets were formed in silicone oil with DC749 or MQ1640 (P<0.05). However, such increase was not directly related to the change in IFT nor viscosity. Moreover, water droplets were also found in the silicone oil, but not in the control silicone oil without additive. The amphiphilic substances in silicone oil promoted emulsification. Besides typical oil-in-water drops that normally affect the eye, water-in-oil drops were also formed. Before silicone oil could be considered as a vehicle for drug delivery, the nature of the drug and its possible effect on emulsification and therefore on the pharmacokinetics needs to be investigated. An additional concern is that water-in-oil droplets in the eye would affect the optical clarity of silicone oil and might cause visual symptoms.

Intraretinal Migration of Emulsified Silicone Oil: Association With Cystoid Macular Edema and Surgical Treatment

Purpose: The purpose of this article is to report the detailed stages of intraretinal silicone oil infiltration, and to describe a new surgical treatment for this condition. Methods: An observational case series is presented. Results: We report 2 patients who had undergone repair of complex diabetic retinal detachment and subsequently developed intraretinal migration of emulsified silicone oil, cystoid macular edema (CME), and lamellar macular hole (LMH). Surgical removal of the incarcerated oil bubbles rapidly restored foveal anatomy in both cases. Possible risk factors for intraretinal oil migration are discussed. Conclusions: Emulsified silicone oil droplets can penetrate the retina, resulting in CME and LMH. While severe CME in this setting is usually recalcitrant to pharmacotherapy, vitrectomy with expression of oil droplets may result in rapid and longstanding resolution.

In Vitro Modeling of Emulsification of Silicone Oil as Intraocular Tamponade Using Microengineered Eye-on-a-Chip.

There is a lack of a standardized methodology or a physiologically realistic in vitro model to investigate silicone oil (SO) emulsification. In this study, we replicated the SO-aqueous interface within a microfluidic chip to study the formation of SO emulsion droplets in the eye cavity. A chip made of poly(methylmethacrylate) was used to represent a cross-section of the posterior eye chamber. A retinal ganglion cell line was coated on the inner surface of the chamber to mimic the surface property of the retina. Silicone oil of different viscosities were tested. The SO-aqueous interface was created inside the chip, which, in turn, was affixed to a stepper-motor-driven platform and subjected to simulated saccadic eye movement for four days. Optical microscopy was used to quantify the count and size of SO emulsified droplets. Among SO of different viscosities, SO 5 centistokes (cSt) emulsifies readily, and a high number of droplets formed inside the chip. Silicone oil 100 cSt led to fewer droplets than 5 cSt, but the droplet count was still significantly higher than other SO of higher viscosities. There were no significant differences in the number of droplets among SO with viscosities of 500, 1000, and 5000 cSt. In all SOs tested, the number of droplets increased, whereas their size decreased with longer duration of simulated saccades. The study platform allows quantification of the number and size of emulsified SO droplets in situ. More importantly, this platform demonstrates the potential of microtechnology for constructing a more physiologically realistic in vitro eye model. Eye-on-a-chip technology presents exciting opportunities to study emulsification and potentially other phenomena in the human eye.

Quantifying silicone oil emulsification in patients: are we only seeing the tip of the iceberg?

Emulsification of silicone oil in the eye is a difficult problem. In an effort to find an objective way to quantify emulsification, we used the Coulter principle to measure silicone oil emulsified droplets from the washings of a series of patients. Aqueous washouts after silicone oil removal were obtained from nine patients (nine eyes). We used the Coulter counter Multisizer® 4 to obtain the size distribution of the oil droplets. Over 65 % of the emulsified silicone oil droplets in the clinical samples had a diameter smaller than is detectable by light microscopy (2 μm). The median size of the droplets was between 1.1 and 1.9 μm. Based on the Spearman's correlation coefficient (r), there was a strong correlation between the number of the droplets that cannot be seen (between 1 and 2 μm) and those that can be seen (7-30 μm) (r = 0.817, p = 0.007). Once emulsification was detected clinically in the anterior chamber, extensive emulsification would have already occurred in the posterior chamber, with most of the emulsified droplets that were too small in size to be seen on clinical examination. Ostwald ripening might explain why there were so many small droplets. The predominance of small droplets might account for some of the clinical complications associated with silicone oil use.

Analysis of the time and location of the silicone oil emulsification by spectral-domain optical coherence tomography after silicone oil tamponade.

Purpose. To estimate localization and the period up to the appearance of small hyperreflective round-shaped droplets using spectral-domain optical coherence tomography (SD-OCT) after pars plana vitrectomy with silicone oil tamponade. Methods. A retrospective observational study included 24 patients who had undergone pars plana vitrectomy with silicone oil tamponade for proliferative vitreoretinopathy (PVR) retinal detachment. SD-OCT analysis was performed 1, 3, and 6 months after surgery. We characterized the emulsified silicone oil in the SD-OCT as the small hyperreflective round-shaped droplets. Results. In SD-OCT examination, none of the patients had hyperreflective round-shaped droplets visible one month after vitrectomy with silicone oil tamponade. The hyperreflective droplets were found three months after surgery—in one patient above the optic nerve and in five patients intraretinally (in the cystoid spaces). Six months after vitrectomy, the hyperreflective round-shaped droplets were still present in the aforementioned patients' eyes and additionally in 3 eyes above the optic disc. Conclusions. Hyperreflective round-shaped droplets were found in a SD-OCT examination 3 months after silicone oil tamponade. The authors suggest that they are most likely the emulsified silicone oil droplets. The authors hypothesize that emulsification and migration of silicone oil begin within 3 months after surgery.

Band Keratopathy From Emulsified Silicone Oil

A well-recognized complication of silicone oil use is the development of band keratopathy. The keratopathy occurs when the silicone oil touches the endothelium and probably results from reduced fluid flow across the cornea with subsequent change in the pH. 1 In some eyes with silicone oil, emulsification of the silicone oil occurs. This produces the tiny droplets of silicone oil that float freely, separated from the major body of the oil. The frequency of this occurrence appears to increase the longer the silicone oil is in the eye and may approach 100%. 2 The presence of emulsified silicone oil droplets in the anterior chamber is not usually associated with keratopathy. 3 We have recently seen a patient with silicone oil in the posterior chamber, which was well separated from his cornea by iris and by a posterior chamber lens, who developed emulsified silicone oil in the anterior chamber. The emulsified