Silicone oil in the repair of complex retinal detachments. A prospective observational multicenter study

Cytomegalovirus Retinitis: Clinical Manifestations, Diagnosis and Treatment

Cytomegalovirus (CMV) retinitis is the most common eye disease associated with CMV infection in immunocompromised individuals. The CMVR may initially be asymptomatic; however, relatively mild vitreous inflammation at the onset may be an important differential point from other diseases in HIV patients. Fundus photography, CD4 T-cell count, and telemedicine could be used to screen and monitor the high-risk population, particularly in resource-limited regions. Retinitis generally starts in the peripheral retina and advances toward the posterior pole, which could develop to the characteristic "pizza pie" appearance marked by central retinal necrosis and intraretinal hemorrhage. CMVR causes vision loss if left untreated, and early antiviral therapy significantly reduces the risk of vision loss. Alongside traditional antiviral treatments, immunotherapies including CMV-specific adoptive T-cell therapy and CMV immunoglobulin (CMVIG) are emerging as promising treatment options due to their favorable tolerability and reduced mortality. This review comprehensively examines CMV retinitis, encompassing the clinical features, differential diagnosis, laboratory tests, and updated treatment strategies to inform clinical management.

Preoperative OCT-Derived Nasal Perifoveal Retinal Nerve Fiber Layer Thickness Predictively Correlates Long-Term Visual Acuity Post Oil Removal Surgery

Purpose

With the widespread application of silicone oil in vitreoretinal surgery, the purpose of this study was to determine the risk factors of long-term vision loss 12 months post oil removal in retina-detached eyes treated with vitrectomy and silicone oil tamponade.

Methods

Of the 592 patients approached, eligible eyes completed the investigation up to 12 months post-oil-removal. Eligible eyes underwent pars-plana vitrectomy following oil tamponade. Oil removal was performed after 3 to 28 months in different individuals, under the condition that the retina has reattached as well as the hemorrhage and inflammation has dissolved. Postoperative best-corrected visual acuity (BCVA), age, sex, and interval between tamponade and removal were recorded, and retinal thickness was determined using optical coherence tomography (OCT).

Results

Fifty eyes of 50 participants aged 31 to 83 years were enrolled. BCVA (LogMAR) 12 months post-oil-removal improved in 25 of 40 (62.5%) patients, varying from 0.05 (20/22) to 1.0 (20/200) (mean ± SD = 0.55 ± 0.32). Pre-oil-removal nasal perifoveal retinal nerve fiber layer thickness varied from 16 to 83 µm (38.40 ± 18.50), and was significantly linked with post-oil-removal BCVA (0.5%, 95% confidence interval 0.0%-1.0%; P = 0.046).

Conclusions

This study demonstrates the risk factors and prognosis of visual function after long-term regeneration post vitrectomy, oil tamponade, and oil removal, thereby underscoring the need for a complete, dynamic examination of retinal structure via OCT measurement. Related studies should be conducted on a larger scale to facilitate the stratification of late-period vision damage in retina-detached eyes.

Translational Relevance

This study developed OCT-based clinical markers for the postoperative visual prognosis of eyes affected by retinal detachment.

Retinal redetachment after silicone oil removal: a risk factor analysis

PURPOSE

To report the rate of retinal redetachment after silicone oil removal following rhegmatogenous retinal detachment surgery and to determine potential risk factors.

METHODS

Retrospective observational case series of 161 eyes who underwent rhegmatogenous retinal detachment surgery and subsequent silicone oil removal. Pre- and intraoperative risk factors were evaluated using univariate and multivariate logistic regression. We also evaluated the effect of tamponade duration on anatomical outcomes.

RESULTS

The median tamponade duration was 5.9 [4.3;7.6] months. Seventeen (10.6%) eyes underwent silicone oil removal within 3 months of surgery, with a median delay of 2.3 [2.0;2.8] months. The rate of retinal detachment after silicone oil removal was 14.9%. A history of previous unsuccessful surgery was the only significant risk factor for retinal redetachment after silicone oil removal (OR 4.8, 95%CI [1.5;19.0], p = 0.02). The use of 360° laser retinopexy and concomitant air or gas tamponade during silicone oil removal were not found to affect the redetachment rate. Eyes with silicone oil tamponade ≤ 3 months showed an increased, albeit not significant, risk of developing recurrent rhegmatogenous retinal detachment after silicone oil removal (35.3% versus 12.5%, p = 0.06).

CONCLUSION

A retinal redetachment occurred in 14.9% of eyes undergoing silicone oil removal following rhegmatogenous retinal detachment surgery. Previous failed surgery was associated with a 4.8-fold increased risk of developing recurrent rhegmatogenous retinal detachment after silicone oil removal. Eyes with silicone oil tamponade ≤ 3 months tended to have a higher redetachment rate.

TRIAL REGISTRATION NUMBER

ID NCT05647928 (12th April 2022).

Electroretinograms Recorded with Skin Electrodes from Post-Vitrectomy Silicone Oil Filled Eyes with Proliferative Diabetic Retinopathy

Purpose

To determine the physiological status of the retina by electroretinography (ERG) using skin electrodes and the RETevalTM system in eyes that had undergone pars plana vitrectomy (PPV) with silicone oil (SO) tamponade. The vitrectomy was performed for a retinal detachment and proliferative diabetic retinopathy (PDR).

Design

Retrospective case series.

Methods

ERGs were recorded with the RETevalTM system (LKC Technologies Inc. Gaithersburg, MD; Welch Allyn, Inc. Skaneateles Falls, NY) from eight eyes with PDR before and after the SO removal. The amplitudes and implicit times of the a- and b-waves of the ERGs before the SO removal were compared to that after the SO removal.

Results

ERGs were recordable in four eyes before and after the SO removal and the a- and b-amplitudes improved in three eyes and worsened in one eye after the SO removal. In the remaining four eyes, ERGs were non-recordable both before and after the SO removal.

Conclusion

These results indicate that ERGs picked up by skin electrodes can be used to assess the physiology of the retina in eyes with a SO tamponade. The flat ERGs in the SO-filled eye indicated the presence of diffuse retinal damage which was confirmed by the flat ERGs after the SO removal.

Emulsification of Silicone Oils: Altering Factors and Possible Complications-A Narrative Review

Background: Endotamponade of the vitreous body with silicone oil is a common procedure, being the basis of many vitreoretinal surgeries. However, emulsification may happen, which is a clinically relevant adverse event of silicone oil use. Methods: This review provides a thorough analysis of the emulsification process. It focuses on describing factors affecting this event as well as its possible subsequent complications. Results: The viscosity of silicone oil, the duration of emulsification, the status of the lens and many other factors have an influence on the onset and intensity of emulsification. This phenomenon carries several risks for operated eyes such as increased intraocular pressure, keratopathy or structural changes to the retina. Conclusions: The use of modern imaging techniques, especially optical coherence tomography, enables faster detection of the emulsification process. This allows for an adequate clinical response and more accurate follow-up of the patient.

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.

Risk Factors and Management of Intraocular Pressure Elevation After Vitrectomy Combined with Silicone Oil Tamponade

Silicone oil has emerged as the common option for intraocular tamponade during complicated retina vitrectomy. However, the postoperative elevation of intraocular pressure (IOP), influenced by numerous factors, remains a significant and frequently encountered complication that poses a potential threat to vision. Extensive research has been conducted to investigate the risk factors associated with elevated IOP following silicone oil tamponade, including silicone oil viscosity, preoperative high IOP, diabetes, and lens status. This comprehensive review aims to gather and summarize the current research findings regarding the risk factors contributing to IOP elevation following silicone oil tamponade, as well as the optimal management strategies for secondary glaucoma. The analysis includes the physicochemical properties of silicone oil, preoperative and intraoperative risk factors, and the effective management of secondary glaucoma. Enhancing our understanding of the primary factors associated with silicone oil-induced IOP elevation will facilitate the guidance of timely and appropriate interventions.

Incidental Finding of Suprachoroidal Space's Silicone Oil Migration: A Tumor-Mimicking Lesion and Its Clinical Management

The migration of silicone oil into the suprachoroidal region is a rare complication of vitrectomy. A 70-year-old man was admitted to our ocular oncology unit with a choroidal elevation in the nasal area, as well as signs of pars plana vitrectomy surgery performed about 5 years ago for retinal detachment. The patient underwent ocular ultrasound, visual field test, fluorangiography, and magnetic resonance imaging, which led to the diagnosis of silicone oil migration in the suprachoroidal space. Silicone oil may move into the suprachoroidal area, mimicking choroidal neoformation. It is important to have a comprehensive diagnosis and then set up the appropriate treatment. [Ophthalmic Surg Lasers Imaging Retina 2024;55:104-108.].

Clinical features of Cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome and efficacy of the current therapy

Background

Cytomegalovirus retinitis (CMVR) is the most common and sight-threatening opportunistic retinal infection in patients with acquired immunodeficiency syndrome (AIDS) and several controversies remain to be settled. We aimed to summarize the current evidence and clarify the clinical features and prognosis of CMVR in AIDS patients.

Methods

The databases PubMed, EMBASE, and Ovid from inception to April 2022 were searched to identify the relevant studies. R software version 3.6.3 was used to perform the statistical analyses. Results in proportion with 95% confidence interval (CI) were calculated using the Freeman-Tukey variant of arcsine square transformation.

Results

We finally included 236 studies comprising 20,214 patients. CMVR in AIDS was male-dominated (88%, 95%CI 86%-89%), with 57% (95%CI 55%-60%) aged <41 years and 44% (95%CI 41%-47%) being bilaterally involved. CMVR was preponderant in AIDS patients with the following characteristics: white and non-Hispanic, homosexual, HIV RNA load ≥ 400 copies/mL, and CD4+ T-cells <50 cells/μL. The positivity of CMV-DNA in blood, aqueous humor, and vitreous humor was 66% (95%CI 52%-79%), 87% (95%CI 76%-96%), and 95% (95%CI 85%-100%), respectively. The most common symptoms were blurred vision (55%, 95%CI 46%-65%), followed by asymptomatic, visual field defect, and floaters. CMVR was first diagnosed and regarded as the clue to AIDS diagnosis in 9% (95%CI 6%-13%) of CMVR patients. Approximately 85% (95%CI 76%-93%) of the CMVR patients have received cART. CMVR remission was observed in 72%-92% of patients depending on the specific category of anti-CMV therapy. The general incidence of CMVR-related RD in the entire course was 24% (95%CI 18%-29%), of which most patients received PPV with SO or gas tamponade and the rate of anatomic success was 89% (95%CI 85%-93%).

Conclusion

CMVR is a common opportunistic infection with diverse clinical features in AIDS patients, preponderant in those who are male, homosexual, or with CD4+ T-cells <50 cells/μL. Current therapies for CMVR and CMVR-related RD were shown to be effective. Early detection and routine ophthalmic screening should be promoted in AIDS patients.

Systematic review registration

PROSPERO, identifier CRD42022363105.

A pilot clinical study of complex rhegmatogenous retinal detachment treatment via foldable capsular buckle scleral buckling

BACKGROUND

To evaluate the feasibility of and identify problems in treating complex rhegmatogenous retinal detachment using foldable capsular buckle scleral buckling.

METHODS

This prospective clinical study enrolled five patients with complex rhegmatogenous retinal detachment treated with foldable capsular buckle scleral buckling at the 988th Hospital of People's Liberation Army Joint Logistic Force, China. During the 24-week follow-up period, the patients underwent measurements of their best-corrected visual acuity, slit-lamp examination, indirect ophthalmoscopy, and visual field testing. Additionally, B-ultrasound and fundus photography of the patients' retinal reattachments helped evaluate the treatment's post-surgery efficacy. We determined the safety of foldable capsular buckle scleral buckling based on infection, eye pain, diplopia, elevated intraocular pressure, and other postoperative severe complications.

RESULTS

All five patients' complex rhegmatogenous retinal detachments were successfully treated and evaluated via B-ultrasound and fundus photography after surgery. Visual acuity was enhanced in four patients 24 weeks after surgery, while the remaining patients developed diplopia after surgery. No other complications were observed.

CONCLUSION

This pilot study preliminarily determined that foldable capsular buckle scleral buckling is feasible for efficient and safe treatment of complex rhegmatogenous retinal detachment. These results support this surgery as a potential and novel alternative to current extraocular procedures for treating complex rhegmatogenous retinal detachment.

TRIAL REGISTRATION

The prospective observational clinical study protocol was approved by the Institutional Review Board and Ethics Committee and registered at the clinical research center in the 988th Hospital of People's Liberation Army Joint Logistic Force, China (9,882,019,000).

Graft Outcomes After Temporary Keratoprosthesis in Combined Penetrating Keratoplasty and Vitreoretinal Surgery

PURPOSE

Corneal pathology can obstruct the visualization required for surgical management of coexisting posterior segment diseases, and use of a temporary keratoprosthesis (TKP) permits combined penetrating keratoplasty (PK) and vitreoretinal surgery. We evaluated graft outcomes after TKP for combined PK and vitreoretinal surgery and analyzed risk factors for graft failure.

METHODS

We reviewed the electronic medical records for patients who underwent TKP for PK combined with vitreoretinal surgery at Wills Eye Hospital between May 2007 and April 2021. Overall, 28 variables were analyzed. The main outcome measure was corneal graft failure, defined as irreversible graft edema or opacification.

RESULTS

A total of 46 eyes of 46 patients underwent combined surgery and were included in the study. The mean age at surgery was 55.7 ± 18.6 years (range 19-86 years), and the mean follow-up was 31.8 ± 30.5 months (range 1.6-114.0 months). Multivariable analysis revealed 2 factors significantly associated with graft failure: history of trauma (hazard ratio = 5.38; 95% confidence interval, 1.53-18.91; P = 0.009) and intraocular silicone oil after transplant (hazard ratio = 5.67; confidence interval 1.66-19.44; P = 0.006). Corneal graft failure occurred in 60.9% of all cases over the course of follow-up, but the absence of both variables yielded a 33.3% failure rate.

CONCLUSIONS

Although outcomes vary, previous ocular trauma and the presence of intraocular silicone oil are risk factors for failure that may facilitate patient selection and improve counseling about long-term graft potential after TKP for combined PK and vitreoretinal surgery.

CLOUDING OF INTRAOCULAR SILICONE OIL IN THE ABSENCE OF EMULSIFICATION

PURPOSE

To describe intraocular clouding of silicone oil in the absence of emulsification.

METHODS

Retrospective observational case series of patients who received silicone oil injections and developed silicone oil discoloration without emulsification after pars plana vitrectomy. Clinical examinations and physicochemical analyses were performed to find out the common cause for the opaque oil.

RESULTS

Thirteen patients developed silicone oil discoloration after pars plana vitrectomy. It could be traced down that all patients had received silicone oil from one respective production batch. The silicone oil was removed as soon as possible after the changes were detected (range, 8-16 weeks). Gas chromatography flame ionization detector, size exclusion chromatography, and high-performance liquid chromatography analysis showed the absence of low-molecular-weight compounds in the opaque lot. Thermogravimetric analysis revealed the opaque lot was more temperature stable. During the follow-ups, no obvious retinal toxicity could be observed and best-recorded visual acuity improved considerably in 12 patients and was only limited by the underlying retinal pathologic conditions.

CONCLUSION

This is the first report on opacification of intraocular silicone oil without emulsification. This discoloration of silicone oil may disturb vision and prevent proper fundus examination; however, it seems to be a nontoxic phenomenon without serious long-term consequences.

Advances in Polysaccharide- and Synthetic Polymer-Based Vitreous Substitutes

The vitreous humour is a gel-like structure that composes the majority of each eye. It functions to provide passage of light, be a viscoelastic dampener, and hold the retina in place. Vitreous liquefaction causes retinal detachment and retinal tears requiring pars plana vitrectomy for vitreous substitution. An ideal vitreous substitute should display similar mechanical, chemical, and rheological properties to the natural vitreous. Currently used vitreous substitutes such as silicone oil, perfluorocarbon liquids, and gases cannot be used long-term due to adverse effects such as poor retention time, cytotoxicity, and cataract formation. Long-term, experimental vitreous substitutes composed of natural, modified and synthetic polymers are currently being studied. This review discusses current long- and short-term vitreous substitutes and the disadvantages of these that have highlighted the need for an ideal vitreous substitute. The review subsequently focuses specifically on currently used polysaccharide- and synthetic polymer-based vitreous substitutes, which may be modified or functionalised, or employed as the derivative, and discusses experimental vitreous substitutes in these classes. The advantages and challenges associated with the use of polymeric substitutes are discussed. Innovative approaches to vitreous substitution, namely a novel foldable capsular vitreous body, are presented, as well as future perspectives related to the advancement of this field.

Effect of silicone oil on retinal microcirculation after vitrectomy for rhegmatogenous retinal detachment evaluated by OCT angiography: a literature review

Silicone oil (SO) has been widely used as intravitreal tamponade agent for rhegmatogenous retinal detachment (RRD) and has been occasionally associated with incomplete retinal structural and functional recovery. The use of Optical Coherence Tomography Angiography (OCT-A) has recently attracted significant attention for detailed analysis of retinal capillary plexus and blood flow changes as predicting factors for postoperative outcomes. A detailed literature search was performed in PubMed database until October 2022. The following keywords were used: rhegmatogenous retinal detachment, silicone oil, optical coherence tomography angiography, macular microvasculature, peripapillary capillary plexus, vessel density, and foveal avascular zone. We identified and reviewed 19 studies referring to microcirculation alterations of the retinal capillary plexus as seen on OCT-A in eyes treated by vitrectomy with intravitreal SO for RRD. A comprehensive update revealed variability of microcirculation characteristics of the retinal capillary plexus including the macular and the peripapillary capillaries. Further studies are warranted to clarify the OCT-A values in an attempt to identify the potential effect of SO on retinal tissue in clinical practice. A review of the existing literature sheds light on the effect of SO on retinal capillary plexus and the potential impact on functional outcomes after vitrectomy for RRD. This article discusses important aspects of key publications on the topic, highlights the importance to identify distinct alterations of the microvasculature status, and proposes the need for further future research in this field.

Translation of hyaluronic acid–based vitreous substitutes towards current regulations for medical devices

PURPOSE

Hydrogel-based vitreous substitutes have the potential to overcome the limitations of current clinically used endotamponades. With the goal of entering clinical trials, the present study aimed to (I) transfer the material synthesis of hyaluronic acid-based hydrogels into a routine, pharmaceutical-appropriate production and (II) evaluate the properties of the vitreous substitutes in terms of the current regulations for medical devices (MDR/ISO standards).

METHODS

The multistep manufacturing process of the vitreous substitutes, including the modification of hyaluronic acid with glycidyl methacrylate, photocopolymerization with N-vinylpyrrolidone, and successive hydrogel purification, was developed under laboratory conditions, characterized using ¹ H-NMR, FT-IR and UV/Vis spectroscopies and HPLC, and transferred towards a pharmaceutical production environment considering GMP standards. The optical and viscoelastic characteristics of the hyaluronic acid-based hydrogels were compared with those of extracted human vitreous and silicone oil. The effect of the hydrogels on the metabolic activity, proliferation and apoptosis of fibroblast (MRC-5, BJ, L929), retinal pigment epithelial (ARPE-19, hiPSC-derived RPE) and photoreceptor cells (661W) was studied as well as their mucosal tolerance via a HET-CAM assay.

RESULTS

Hyaluronic acid-based hydrogels having a suitable purity, sterility, high transparency (>90%), appropriate refractive index (1.3365) and viscoelasticity (G' > G″) were prepared in a standardized manner under controlled process conditions. The metabolic activity, proliferation and apoptosis of various cell types as well as egg choroid were unaffected by the hyaluronic acid-based vitreous substitutes, demonstrating their biocompatibility.

CONCLUSIONS

The present study demonstrates the successful transferability of the crucial synthesis steps of hyaluronic acid-based hydrogels into a routine, GMP-compliant production process while achieving the optical and viscoelastic properties, biocompatibility and purity required for their clinical use as vitreous substitutes.

Clinical Application of Foldable Capsular Vitreous Bodies in the Treatment of Severe Ocular Trauma and Silicone Oil Dependent Eyes

Purpose

This study aimed to assess the application of a foldable capsular vitreous body (FCVB) in the treatment of severe ocular trauma and silicone oil (SO) dependent eyes.

Methods

A retrospective analysis was performed on the clinical application of FCVB in the treatment of severe ocular trauma and SO dependent eyes. The results of best-corrected visual acuity and intraocular pressure (IOP) evaluation, B-scan ultrasonography or color Doppler ultrasonography, ultrasound biomicroscopy, and anterior segment photography were recorded during follow-up. A paired t-test was used to compare the difference in IOP before and after FCVB implantation.

Results

Seven eyes of seven patients were included in the 6-month follow-up. In all cases, B-scan ultrasonography and ultrasound biomicroscopy showed that FCVB adapted closely to the globe wall and ciliary body, thus supporting the retina. Visual acuity did not improve, except in one case from LP to HM. The mean ± SD IOP was 8.5 ± 1.90 mm·Hg prior to FCVB implantation and 10.43 ± 0.98 mm·Hg after implantation, with no significant difference between these measurements (P=0.095). Five of the seven patients developed differing degrees of corneal opacity and keratopathy.

Conclusions

FCVB implantation may be a safe and effective method for the treatment of severe ocular trauma and SO dependent eyes. However, FCVB cannot prevent the phthisis of the traumatic eyes. In addition, corneal opacity and keratopathy are potentially serious complications after surgery. Appropriate case selection and proper surgical timing are required for further investigation.

Vitreous Substitutes as Drug Release Systems

Vitreous substitutes are traditionally used to stabilize the retina after vitrectomy. In recent years, various approaches have been developed for using the vitreous substitute not only as a tamponade but also as a drug release system to tackle ocular diseases. This review provides an overview of the requirements for vitreous substitutes and discusses the current clinically applied as well as novel polymer-based vitreous substitutes as drug delivery systems, including their release mechanisms, efficiencies, challenges, and future perspectives.

Incidence and Risk Factors Affecting the Recurrence of Primary Retinal Detachment in a Tertiary Hospital in Spain

(1) Objective: To determine the incidence, visual outcomes and risk factors associated with the recurrence of primary retinal detachment (RD) in a tertiary hospital. (2) Methods: A retrospective observational study was conducted, and data were collected on all eyes diagnosed with primary RD between January 2017 and December 2020. A detailed database was generated with data on anatomic and visual outcomes, and surgical technique information, for all the cases. (3) Results: 570 eyes with primary RD were included. Mean annual incidence of primary RD was 21.8 cases per 100,000 inhabitants. Mean follow-up time was 465 (±410.5) days. Mean time to redetachment was 114.4 (±215.8) days, with the median being 35 days. Statistically significant variables related to a higher risk of recurrence were: male sex (p = 0.04), type of tamponade (p = 0.01), surgeon (p = 0.035), inferonasal (p = 0.002) and inferotemporal (p = 0.032) involvement, complex RD (p < 0.001) and ocular comorbidity (p < 0.001). More satisfactory final visual acuity (VA) in patients not suffering redetachment was associated with shorter duration of central vision loss. (4) Conclusions: Sex, type of tamponade, inferior detachment, RD complexity, surgeon and ocular comorbidity were identified as prognostic factors for recurrence. Worse final postoperative VA was found in patients referring central vision loss for more than 4 days before surgery.

The novel use of high-flow polyimide cannulas to improve silicone oil injectability in vitreoretinal surgery

PURPOSE

The injection of high-viscosity silicone oil lengthens injection time. New polyimide-cannulas offer a greater inner diameter than conventional metal-cannulas at the same gauge. We compared the injection time for polyimide- and metal-cannulas at 23G for a variety of silicone oils including a 12500 mPas prototype oil.

METHODS

In this laboratory study, injection time was measured three times per cannula and per oil. Warming the oil before injection to up to 42°C was also evaluated. Finally, we tested the feasibility of polyimide-cannulas in vitrectomized porcine eyes.

RESULTS

The 23G-polyimide-cannula majorly decreased injection times. The time to inject 5ml of Siluron Xtra and Siluron 5000 decreased by 6:02 (76.9%) minutes (483 s vs 121 s) and 12:01 (74.7%) minutes (973 s vs 252 s), respectively. While the 23G-metal cannula failed to inject 12500 mPas oil, 5ml were injected in 10:21 minutes using the polyimide-cannula. Pre-warming Siluron 5000 to 42°C lowered the injection time by 9.0% and 12.1% when using the metal or polyimide-cannula, respectively.

CONCLUSION

Polyimide-cannulas allow a clinically relevant decrease in injection time. They may not only shorten surgery time but could ease the use of next-generation ultra-high-viscosity silicone oils. Pre-warming silicone oil leads to decreased injection times.

Physicochemical Properties of Explanted Silicone Oil After Use as an Intraocular Tamponade

Purpose

We studied the effects of exposure to biological media within the eye, such as contamination with lipophilic and amphiphilic substances, on the physicochemical parameters of silicone oil used as an intraocular tamponade.

Methods

We removed silicone oil with visible emulsification from 15 patients and measured each sample for shear viscosity and surface tension. We induced in vitro emulsification with balanced salt solution. Using the zeta-potential, we evaluated the emulsion droplet's electrochemical stability. We repeated all experiments in a control group of unused oil. Electrochemical stability and viscosity were additionally measured in oils with high-molecular-weight components.

Results

We recovered silicone oils implanted between 30 and 506 days (mean, 196 days). Viscosity did not differ between explanted and control groups. Surface tension and zeta potential remained unchanged (P = 0.61 and P = 0.84, respectively). All oils showed a significant correlation of viscosity with temperature (P < 0.01 for all). Oils with added high-molecular-weight components showed a lower emulsion stability.

Conclusions

Prolonged contact to hydrophilic biological media does not alter high-viscosity silicone oil's physicochemical parameters. During typical durations of intraocular use, lipophilic and amphiphilic molecules had no deleterious effect. The addition of high-molecular-weight components might decrease the silicone oil's electrochemical emulsion stability, possibly easing the confluence of emulsion droplets.

Translational Relevance

Although the physicochemical parameters of silicone oils are not altered after clinically relevant durations within the eye, emulsion stability significantly differs between oil types.

Macular microcirculation changes after macula-off rhegmatogenous retinal detachment repair with silicone oil tamponade evaluated by OCT-A: preliminary results

Background:

Rhegmatogenous retinal detachment (RRD) with macular involvement is a sight-threatening condition. Silicone oil (SO) is efficacious for retinal tamponade, especially in complex cases. Whether macular detachment per se or the potential tamponading agent may affect macular microcirculation after RRD repair is a matter of research.

Objectives:

To investigate macular microcirculation changes using optical coherence tomography angiography (OCT-A) after pars plana vitrectomy (PPV) with intravitreal SO for RRD repair in the early posttreatment period.

Design:

Prospective comparative cross-sectional study.

Data sources and Methods:

Fourteen eyes of 14 patients were included in the study. All eyes underwent a single successful PPV with SO tamponade for macula-off RRD. OCT-A was performed to analyze macular microcirculation and visual outcomes at 1 month postoperatively. The fellow unaffected eye was used as control.

Results:

Vessel density (VD) in the superficial capillary plexus (SCP) was significantly lower at each macular region (fovea, parafovea, and perifovea) of SO-treated eyes compared with the fellow eyes (all p = 0.001). Similarly, perfusion density (PD) in the SCP was significantly lower at each macular region than the fellow eyes (all p = 0.001). There was enlargement of foveal avascular zone (FAZ) area and decrease of circularity at RRD eyes compared with the fellow ones (all p = 0.001). Postoperative logMAR visual acuity (VA) was significantly lower in treated eyes than fellow eyes and correlated inversely with foveal, parafoveal, and perifoveal VD and PD SCP (all p < 0.001). Postoperative VA had no correlation with FAZ parameters.

Conclusion:

Enlargement of FAZ SCP and decrease in VD and PD SCP during the short-term follow-up were possibly attributable to ischemic changes in the macular area after RRD repair with SO tamponade. In this preliminary study, the flow density in macular capillary plexus may represent an indicator of visual outcomes.

Effect of Duration of Silicone Oil Tamponade on Retinal Structure after Rhegmatogenous Retinal Detachment Surgery

PURPOSE

The aim of the study was to investigate the effect of tamponade duration on retinal changes induced by silicone oil (SO) in patients who underwent successful rhegmatogenous retinal detachment (RRD) surgery.

METHODS

Retrospective comparative case series of 68 patients who underwent SO tamponade for RRD. Patients were divided into 2 groups based on timing of SO removal: <6 months (group 1, n = 34) versus ≥6 months (group 2, n = 34). The main outcome measure was the change in central macular, inner, and outer retinal layer thickness (CMT, IRLT, and ORLT) before and after SO removal (SOR).

RESULTS

The median tamponade duration was 4 [Clin Ophthalmol. 2016;10:471-6, Zhonghua Yan Ke Za Zhi. 1997 Jan;33(1):39-41] months in group 1 and 8 [Arch Ophthalmol. 1994 Jun;112(6):778-85, Retina. 2004 Dec;24(6):871-7] months in group 2 (p < 0.001). The mean CMT significantly increased from 245.3 ± 22.2 μm and 238.8 ± 41.6 μm under SO to 281.3 ± 60.2 μm and 259.0 ± 43.5 μm after SOR in group 1 (p = 0.009) and in group 2 (p = 0.007), respectively. Automated segmentation measurement revealed a significant increase in mean IRLT (p = 0.014 and p = 0.013) but no change in mean ORLT (p = 0.080 and p = 0.257) in both groups. After adjustment, there was no difference between the 2 groups in terms of mean final CMT, IRLT, and ORLT and mean retinal thickness changes after SOR. There was also no correlation between the tamponade duration and macular microstructural changes or visual recovery.

CONCLUSION

SO tamponade causes a thinning of all retinal layers, mainly affecting the inner retinal layer. However, these changes resolved following SO extraction and were not affected by longer tamponade duration.

The effect of silicone oil tamponade on retinal layers and choroidal thickness in patients with rhegmatogenous retinal detachment: a systematic review and meta-analysis

Background

To evaluate the effects of intravitreal silicone oil (SO) on the retinal and choroidal thickness in eyes with rhegmatogenous retinal detachment (RRD).

Methods

A literature search was performed in Web of Science, Scopus, ProQuest, Embase, Clinical Key, Science Direct, Cochrane Library, and Springer, as well as Persian databases, including IranDoc, MagIran, SID, MOH thesis, and MOH articles until June 2020. Two reviewers independently searched and extracted the data.

Results

Sixteen studies (n = 391) met the inclusion criteria. The meta-analysis showed that the SO tamponade could significantly reduce the central macular thickness (CMT) in patients with RRD as compared to gas tamponade WMD = − 14.91; 95% CI: − 22.23, − 7.60; P < 0.001, I² = 71%). No significant change was found in CMT between the eye with SO tamponade (after SO removal) and the fellow healthy eye in patients with RRD (WMD = − 3.52; 95% CI: − 17.63, 10.59; I² = 68.6%). Compared to the preoperative stage, the SO tamponade could significantly reduce the subfoveal choroidal thickness in patients with RRD (WMD = − 18.67, 95% CI: − 30.07, − 1.28; I² = 80.1%). However, there was no significant difference in the subfoveal choroidal thickness before and after SO removal (WMD = − 1.13, 95% CI: − 5.97, 3.71; I² = 87.6%).

Conclusion

The SO tamponade had a significant effect on the reduction of retinal layers and the subfoveal choroidal thickness.

Analysis of retinal detachment resulted from post-operative endophthalmitis treated with 23G pars Plana Vitrectomy

Background

To evaluate the rate, risk factors, functional outcome and prognosis in eyes with retinal detachment after post-operative endophthalmitis treated with 23G Pars Plana Vitrectomy.

Methods

Electronic patient files from 2009 until 2018 were screened for the presence of an endophthalmitis. Included were 116 eyes of 116 patients. This population was evaluated for the rate of retinal detachment after 23G Pars Plana Vitrectomy for endophthalmitis following cataract surgery or intravitreal injection. The main outcome measures were retinal detachment and visual acuity.

Results

The reasons for endophthalmitis were previous cataract surgery in 78 patients and following intravitreal injection in 38 patients. The first clinical evidence of endophthalmitis was present in median 5 days after the triggering intervention. Twenty-five eyes (21.55%) developed a retinal detachment an average of 25 days after endophthalmitis. RD is significantly associated with preoperative visual acuity (p = 0.001).

Conclusions

We emphasize the prognostic role of preoperative visual acuity in RD development of the endophthalmitis treated with 23G Pars Plana Vitrectomy.

Corneal endothelial changes induced by pars plana vitrectomy with silicone oil tamponade for retinal detachment

Silicone oils are effective intraocular tamponade agents in the treatment of severe retinal detachments, because they maintain the adhesion between neurosensory retina and retinal pigment epithelium, thanks to their ability to remove aqueous humor from the surface of the retina. To understand their effectiveness, it is important to know the characteristics of silicone oils. Patients should be closely monitored due to many complications associated with intraocular silicon oil, such as inflammatory reaction, raised intraocular pressure, refraction disorders, cataract, and emulsification. This study presents corneal endothelial changes and some intraocular complications caused by silicone oil used as an intraocular tamponade agent in the case of vitrectomy for complex retinal detachments. The aim of the study was to demonstrate the damage of corneal endothelial cells after the use of silicone oil in patients with retinal detachment surgery. Endothelial specular microscopy measurements were performed and the changes of the following parameters demonstrated the corneal damage: Mean cell density, coefficient of variation, average cell area, percentage of hexagonal cells, and corneal thickness. Three months postoperatively, a statistically significant decrease was observed in the following analyzed parameters: Mean cell density (P=0.04), and percentage of hexagonal cells (P=0.002); the remaining parameters also had a linear decrease (coefficient of variation, average cell area), but were statistically insignificant. Three months postoperatively, the corneal thickness presented a slight increase. Silicone oils are powerful tools when used wisely and within the limits of their use. These are often recommended in cases of severe detachment of the retina in patients at high risk of experiencing intraoperative complications.

Silicone oil versus gas tamponade for primary rhegmatogenous retinal detachment treated successfully with a propensity score analysis: Japan Retinal Detachment Registry

Background/aims

To compare the effects of silicone oil tamponade (SOT) to that of gas tamponade (GT) on the best-corrected visual acuity (BCVA) after successful vitrectomy for retinal detachment (RD).

Methods

A retrospective, multicentre, nationwide study with RD who were registered in the Japan-RD Registry. All cases with RD treated with successful vitrectomy between February 2016 and March 2017 were studied. A propensity score matching was performed using the preoperative findings as covariates to adjust the relevant confounders. The primary outcome was the estimated mean difference of the postoperative BCVA in 6 months between eyes treated with SOT to those treated with GT.

Results

Of the 3446 cases registered, 2097 cases met the entry criteria. There were 2042 eyes that had GT and 55 eyes that had SOT. Primary success was defined as a reattached retina with no tamponade at 6 months. After propensity score matching, each group contained 40 cases. The preoperative BCVA was 0.966±0.738 logMAR units in the GT group and 1.270±0.945 logMAR units in the SOT group (p=0.177). Six months postoperatively, the BCVA in the GT group was significantly better at 0.309 logMAR units in the GT group than the 0.671 logMAR units in the SOT group (p=0.002).

Conclusions

Even after successful surgery for RD, eyes that experienced SOT had poorer BCVA than eyes treated with GOT. SOT should be considered cautiously.

Precis

Propensity score analysis of eyes with rhegmatogenous RD showed that postoperative vision was worse in eyes treated once with silicone oil than with gas even after completely successful surgery.

Retinal electrophysiological changes related to early versus late silicone oil removal

PURPOSE

To compare between the effect of early (3 months) and late (6 months) silicone removal on the electroretinogram records.

METHODS

Thirty-four eyes with complex primary rhegmatogenous macula off retinal detachment undergone vitrectomy. Silicone oil was removed after 3 months in group I and after 6 months in group II. Scotopic and photopic ERGs, pattern electroretinogram (PERG) and multifocal ERG (mfERG) and best-corrected visual acuity (BCVA) were recorded for all eyes RESULTS: Preoperative mean best corrected visual acuity (BCVA) measured was 0.93 ± 0.05 in group I and 0.9 ± 0.08 in group II. One month after silicone removal, mean BCVA was 0.20 ± 0.04 and 0.18 ± 0.02 in groups I and II respectively. Before silicone oil removal the electroretinographic a- and b-waves were greatly reduced in both groups with no significant difference between them. One month after removal of silicone oil, the electroretinographic a- and b-waves increased in both groups with no significant difference between the two groups (p = 0.46 and 0.23 respectively).

CONCLUSION

The amplitudes of the ERGs increase after removal of silicone oil tamponade with no difference between early (3 months) and late (6 months) removal.

Analysis of the Changes in Retinal Thickness in Eyes Undergoing Vitrectomy with Silicone Oil Tamponade

Purpose: To investigate changes in the retinal layer thickness in rhegmatogenous retinal detachment (RRD) and intraocular foreign body (IOFB) patients undergoing successful pars plana vitrectomy (PPV) with silicone oil tamponade. Methods: This retrospective study included 28 eyes of 28 patients (RRD: 24 patients; IOFB: 4 patients) that were successfully repaired with PPV with silicone oil tamponade. The thickness measurements of the total retina, retinal nerve fiber layer (RNFL), and ganglion cell-inner plexiform layer (GC-IPL) were performed with swept-source optical coherence tomography in nine Early Treatment Diabetic Retinopathy Study subfields, using the wide three-dimensional mode before and after silicone oil tamponade removal. The measurements were compared and differences were analyzed with respect to normal fellow eyes. Results: The RNFL and GC-IPL thickness measurements decreased remarkably as the silicone oil tamponade period progressed, compared with the thickness of the total retinal layer. The average thicknesses of the total retina, RNFL, and GC-IPL were significantly greater in eyes in which the silicone oil had been removed than in those in which the silicone oil remained. Conclusions: Silicone oil tamponade can change the thickness of the retina layer. The longer the silicone oil is tamponaded, the more significant the reduction in thickness of the inner retinal layer.

Long-term silicone oil tamponade in eyes with complicated retinal detachment

PURPOSE

To report the visual and anatomic outcomes of eyes with exceedingly long-term silicone oil tamponade.

METHODS

A retrospective chart review of 43 eyes of 41 patients with silicone oil tamponade for 5 years or more. Rates of retinal reattachment, visual acuity, and complications are presented. Further analysis was performed to identify if silicone oil complications are more common in eyes with lower vision. For this, cases were divided into group A-visual acuity of 20/400 or better and group B-visual acuity of less than 20/400.

RESULTS

Mean silicone oil duration was 12.6 ± 6.3 years. The etiology at presentation included: recurrent RRD (60.46%), RRD secondary to trauma (25.58%), and TRD (13.95%). Ninety-three percent of eyes underwent at least one ocular surgery before the vitrectomy with silicone oil tamponade. The retinal attachment rate was 55.8%. Mean visual acuity at presentation was 2.03 ± 0.6 logMAR, and at the final follow-up, 1.85 ± 0.78 logMAR (p = 0.166). Emulsification developed in 33.3% of cases, glaucoma in 28.6%, band keratopathy in 21.4%, and corneal decompensation in 16.7%. In 26.2% of eyes, the final visual acuity was 20/400 or better (group A). In 73.8% of eyes, final visual acuity was worse than 20/400 (group B). The rates of silicone oil emulsification and glaucoma were not statistically significant between groups.

CONCLUSIONS

Long-term silicone oil tamponade is a possible option in eyes with complicated retinal detachment following multiple intravitreal procedures, although the complication rates are relatively high. In 26.2% of eyes, visual acuity of 20/400 or better can be preserved for many years.

LABORATORY EVALUATION OF INTRAOCULAR SILICONE OIL REMOVED AFTER 23 YEARS IN SITU

PURPOSE

To report the clinicopathologic correlation and biochemical analysis of silicone oil removed after 23 years in an eye.

METHODS

A 63-years-old man with a history of HIV/AIDS and cytomegalovirus retinitis, status post retinal detachment repair with silicone oil at the age of 39 years, presented with several weeks of worse vision. He was found to have a shallow fovea-off tractional retinal detachment. After the silicone oil was removed during retinal detachment repair, it was analyzed by Fourier-transform infrared spectroscopy and gas chromatography with mass spectrometry.

RESULTS

In addition to cyclic and linear silicone oil, cholesterol was found in the removed silicone oil, which was not present in unused silicone oil samples. No other chemical alterations were identified in the extracted silicone oil.

CONCLUSION

Silicone oil left inside an eye over an extended period may extract lipophilic substances from adjacent tissue, with possible pathophysiologic effects. However, no other major potentially toxic substance was identified from the long-standing silicone oil sample, suggesting relative chemical stability of the tamponade agent over time.

Substitutes and Colloidal System for Vitreous Replacement and Drug Delivery: Recent Progress and Future Prospective

Vitreoretinal surgeries for ocular diseases such as complicated retinal detachment, diabetic retinopathy, macular holes and ocular trauma has led to the development of various tamponades over the years in search for an ideal vitreous substitute. Current clinically used tamponade agents such as air, perfluorocarbons, silicone oil and expansile gases serve only as a short-term solution and harbors various disadvantages. However, an ideal long-term substitute is yet to be discovered and recent research emphasizes on the potential of polymeric hydrogels as an ideal vitreous substitute. This review highlights the recent progress in the field of vitreous substitution. Suitability and adverse effects of various tamponade agents in present day clinical use and biomaterials in the experimental phase have been outlined and discussed. In addition, we introduced the anatomy and functions of the native vitreous body and the pathological conditions which require vitreous replacement.

Surgical Management for Silicone Oil Barrier of Traumatic Aniridia with Aphakia: Suturing of Temporary Iris-Diaphragm Prior to Final Iris-Lens-Diaphragm Implantation

Purpose

Patients with traumatic aniridia, aphakia and retinal complications can require silicone oil endotamponade. In the absence of compartmentalization, there is a risk of silicone oil migrating to the anterior chamber which can cause long-term complications. We report a two-step procedure in trauma cases, using sutures for silicone oil retention in primary care and subsequently prior to secondary artificial iris (AI) and intraocular lens (IOL) implantation, to achieve a reconstruction of the anterior and posterior chamber.

Material and Methods

Seven patients with loss of the iris-lens-diaphragm after an ocular trauma and the need for silicone oil endotamponade underwent a primary intervention including wound closure, placement of silicone oil retention sutures and silicone oil filling. Four of those underwent secondary reconstruction with silicone oil removal and AI and IOL implantation and could be included in this retrospective observational study. All main outcome measures were evaluated after the first and after the second surgery. The main outcome measures were morphological findings, subjective impairment from glare, subjective cosmetic disfigurement, patient satisfaction and intraocular pressure (IOP) as well as best-corrected distance visual acuity and objective refraction.

Results

The retention sutures could effectively prevent silicone oil migration into the anterior chamber in the first surgery. Silicone oil emulsifications in the anterior chamber were observed in one patient. In two patients, pigment deposition at the sutures was seen. Subjective impairment from glare and subjective cosmetic disfigurement could be reduced after the second surgery compared to the evaluation after the first surgery. IOP and best-corrected distance visual acuity remained stable. No eye needed silicone oil refilling after the secondary reconstruction surgery.

Conclusion

Our two-step approach is viable and provides good functional and aesthetic results. We observed a high patient satisfaction.

Intraventricular Silicone Oil Migration Resembling Hemorrhagic Complication in a Patient with Ischemic Stroke Receiving Antithrombotic Therapy

We report herein a case of intraventricular silicone oil migration, a rare complication of intraocular silicone oil tamponade, mimicking a hemorrhage during antithrombotic therapy for ischemic stroke. A 62-year-old male patient with a history of diabetic retinopathy was admitted for right hemiparesis and dysarthria. Brain magnetic resonance imaging on admission showed an acute left-sided ventral medullary infarction, and antithrombotic therapy was started. Head computed tomography done on the next day after admission showed an area of high-density resembling a hematoma in the lateral ventricle. Additional magnetic resonance imaging in the supine and lateral recumbent positions confirmed migration of the lesion within the ventricles by position, indicating intraventricular silicone oil migration. Several facilities in Japan perform magnetic resonance imaging instead of computed tomography as the first step in assessing stroke in the emergency clinical setting. While the silicone oil used in internal tamponade appears high-density on computed tomography, it does not register as an abnormality on diffusion-weighted imaging, thus creating a pitfall to diagnosis based on this modality.

Surgical outcomes and prognostic factors following vitrectomy in acquired immune deficiency syndrome patients with cytomegalovirus retinitis-related retinal detachment

To determine the surgical outcomes and prognostic factors of cytomegalovirus (CMV) retinitis-related retinal detachment (RD) in acquired immune deficiency syndrome (AIDS) patients following vitrectomy.A retrospective charts review was carried out on AIDS patients who were diagnosed with CMV retinitis-related RD and treated with vitrectomy between 2002 and 2016. The main outcome measures were the rates of primary anatomical success and final visual acuity (VA) success defined as postoperative VA ≥20/200. Kaplan-Meier curves on the time to retinal redetachment were performed. Multivariate logistic regression models based on a directed acyclic graph were used to identify independent factors associated with achieving VA success.Forty five AIDS patients (52 eyes) were included. Over a mean follow-up period of 41.7 months, primary anatomical success was achieved in 44 eyes (84.6%) and VA success was achieved in 34 eyes (65.4%). Receiving highly active antiretroviral therapy (HAART) prior to RD (adjusted odds ratio [aOR]=4.9, P = .043), better preoperative VA (aOR = 4.3, P = .006), undergoing vitrectomy within 3 months (aOR=6.7, P = .008), absence of optic atrophy (aOR=58.1, P < .001), and absence of retinal redetachment (aOR=38.1, P = .007) increased the odds of achieving final VA success.Vitrectomy provided favorable anatomical reattachment in AIDS patients with CMV retinitis-related RD. Majority of patients was able to retain functional vision postoperatively. The use of HAART and early vitrectomy increased the probability of achieving both anatomical and VA success.

Characteristics, fates and complications of long-term silicone oil tamponade after pars plana vitrectomy

BACKGROUND

Silicone oil tamponade has become a mainstay in treatment of advanced retinal detachment due to multiple etiologies. The aim of this study is to assess the characteristics, fates and complications of long-term silicone oil tamponade after par plana vitrectomy (PPV), and to compare the outcomes of different silicone oil viscosities used in a cohort of consecutive patients.

METHODS

This is a retrospective comparative case series of eyes undergoing vitrectomy with silicone oil tamponade for retinal detachment by a single surgeon using different oil viscosities that were followed for one year with the silicone oil in situ. Visual acuity (VA), intraocular pressure (IOP) and complications associated with the follow up period were analyzed and compared.

RESULTS

Eighty-five eyes of 85 patients were included in this study. Forty three patients had 1000 centistoke (cs) oil injected and 42 patients had 5000cs oil utilized. Demographic, cause of retinal detachment and preoperative ocular characteristics were similar in both groups. Long term complications in both groups included ocular hypertension (67.4% vs 66.7%), keratopathy due to silicone oil emulsification and migration to the anterior chamber (7.0% vs 11.9%), recurrent retinal detachment (4.7% vs 19%) and epiretinal membrane formation (7% vs 19%). In the 1000cs oil group, there was no significant difference between baseline IOP and any subsequent visit. There was a significant difference between baseline IOP and visits at day 1 (with IOP difference of 2.61 mmHg (±6.5)) (p = 0.028), 1 month (with IOP difference of 3.52 mmHg (±8.1)) (p = 0.026), 4 months (with IOP difference of 6.38 mmHg (±9.3)) (p = 0.005), and one year (with IOP difference of 4.24 mmHg (±11.1)) (p = 0.048), all higher in the post-operative period in the 5000cs oil group. Excluding the first post-operative day, no significant difference was found for VA between baseline visits and subsequent visits for either silicone oil groups.

CONCLUSION

In this cohort of patients with long-term silicone oil tamponade after PPV to treat retinal detachment, IOP increased significantly in patients who received 5000cs silicone oil. There was no significant difference between other complication rates in patients receiving either oil viscosities. Long term silicone oil tamponade remains a viable option in certain cases, and a vigilant follow up for complications is necessary to limit any adverse effects and improve visual and surgical outcomes.

Intraocular Pressure Rise Linked to Silicone Oil in Retinal Surgery: A Review

Silicone oil represents the main choice for intraocular tamponade in cases of complicated retinal detachment surgery. The intraocular pressure of an eye filled with silicone oil could increase, driven by a variety of different forces, according to several mechanisms. Two main conditions have been highlighted, depending on the onset: early hypertension or late glaucoma. The different types of silicone oils and their physico-chemical properties are varied and may play a role in the determination of intraocular pressure rise. The current body of literature allows for the illustration and categorization of the incidence and risk factors, as well as the pathogenesis and the management of the early postoperative hypertension subtended by an open- and closed-angle, along with the late onset silicone oil-induced glaucoma. Understanding the leading actors on the stage of ocular pressure elevation concurrently with silicone oil application for retinal surgery could help in guiding the timely and appropriate course of treatment.

Unexplained Visual Loss After Silicone Oil Removal: A 7-Year Retrospective Study

Introduction

Unexplained visual loss after removal of silicone oil from the eye has been described. The purpose of this study is to determine the incidence of unexplained loss of visual acuity after SO removal and to provide possible explanations for this phenomenon.

Methods

This retrospective study included patients that underwent vitreoretinal surgery, at Centro Hospitalar São João, between January of 2012 and October of 2018. Inclusion criterion was vitreoretinal surgery in which the chosen endotamponade was SO, followed by removal of SO and exchange with balanced salt solution (BSS) or air. After SO removal, patients with documented loss of best corrected visual acuity (BCVA) on two or more Snellen lines were analyzed and patients in which the cause of the visual loss was identified, namely OHT (intraocular pressure > 21 mmHg), retinal re-detachment, glaucoma, retinal proliferative membrane formation, or corneal decompensation, were excluded. All patients with unexplained visual loss underwent spectral domain optical coherence tomography (SD-OCT) to exclude causes of visual reduction such as cystoid macular edema, epiretinal membrane, or ellipsoid/interdigitation zone disruption. A p value less than 0.05 was considered statistically significant.

Results

A total of 46 eyes underwent SO tamponade and SO removal during the study period. In 34.8% of the cases (n = 16) there was visual acuity loss in at least two Snellen lines. Of 46 eyes, 23.9% (n = 11) showed vision loss due to known secondary causes. Unexplained loss of visual acuity after SO removal occurred in 10.9% of cases. OHT during silicone endotamponade (p = 0.046) and silicone emulsification (p = 0.001) were identified as factors associated with unexplained visual loss after SO removal.

Conclusion

Unexplained loss of visual acuity after SO removal occurred in 10.9% of cases. OHT during silicone endotamponade and SO emulsification were identified as important factors in the ethology of this phenomenon.

Prognostic Factors for Outcome after Vitrectomy for Retinal Detachment Secondary to Cytomegalovirus Retinitis in Patients with AIDS: A Retrospective Single-center Analysis

Purpose: To analyze the clinical characteristics and relevant prognostic factors of vitrectomy for retinal detachment (RD) secondary to cytomegalovirus retinitis (CMVR) in patients with acquired immune deficiency syndrome (AIDS).Methods: This study involved 39 eyes that underwent vitrectomy. Best-corrected visual acuity (BCVA), CD4⁺ cell counts, retinal attachment rate, and prognostic factors were assessed 1, 3, and 6 months postoperatively.Results: The rate of retinal attachment at 1 month (87.2%) was higher than at 3 (82.1%) and 6 (71.8%) months. Factors significantly related with recurrent RD at 6 months were CD4⁺ cell count <50 cell/µL (p = .000) and relaxed retinotomy (p = .002). Factors significantly related with the visual (≤logMAR1.0) prognosis at 6 months include band keratopathy (p = .015) and macular involvement by the RD (p = .012).Conclusion: CD4⁺ cell counts <50 cell/µL and relaxed retinotomy are associated with worse prognosis, while band keratopathy and macular involvement by the RD are related to poorer vision.

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.

Retinal Tamponades: Current Uses and Future Technologies

Purpose of Review

In this article, the current use and limitations of existing retinal tamponades are discussed. Potential novel developments that address those limitations are subsequently highlighted, along with areas of future improvements.

Recent Findings

While retinal tamponades have existed for decades and improved the treatment of retinal detachments, many problems still exist with their use, including inadequate tamponade of the inferior retina, toxicity from retained heavy liquids, glaucoma, and keratopathy, among others. New advancements in the components of heavy liquids and vitreous substitutes aim to mitigate those issues.

Summary

Existing retinal tamponades, including perflurocarbon heavy liquids, fluorinated gases, and silicone oil, have specific limitations that cause potentially avoidable morbidity. New developments, such as heavy silicone oil, novel vitreous gels, and future avenues of approach, such as potentially reabsorbing heavy liquids may help increase our ability to treat retinal detachments with fewer complications.

Comparison of hydrophilic ophthalmic media on silicone oil emulsification

The aim of this study was to investigate whether and how the biological media which are in contact with silicone oil play a role in the silicone emulsification process.

Commercially available Oxane 1300 silicone oil and potential hydrophilic phases of the emulsions in the eye (porcine aqueous humor, porcine vitreous and balanced salt solution) were investigated separately and in a mixture or emulsions by means of surface tension, rheological, zeta potential measurements and microscopic investigation.

The surface tension of biological media (vitreous and aqueous humor) was significantly lower than that of non-biological media, especially in the case of aqueous humor, which indicates a remarkable emulsification tendency with these phases. The biological media are able to form both oil-in-water and water-in-oil emulsions, which can be observed in the clinical practice as well. It was established that the vitreous has a more expressed emulsification ability compared with the aqueous humor because smaller and more stable droplets can form with silicon oil when the vitreous is still there. It can be concluded that the vitreous has a higher impact on emulsification than the aqueous medium, which can predict that the vitreous remaining after vitrectomy has a key role in emulsion formation in the eye with silicone oil endotamponade.

Anatomical and functional results of ILM peeling vs. non-peeling in macula-off rhegmatogenous retinal detachment

PURPOSE

To compare anatomical and functional results between internal limiting membrane (ILM) peeling and non-ILM peeling in macula-off rhegmatogenous retinal detachment (RRD).

METHODS

We completed a retrospective cohort study of patients who underwent pars plana vitrectomy (PPV) due to macula-off RRD. ILM peeling (P) versus non-ILM peeling (NP) groups were compared regarding best-corrected visual acuity (BCVA), anatomical success, endotamponade, concomitant scleral band placement and BCVA gain for epiretinal membranes (ERM) resubjected to PPV. Statistical significance was considered when p < 0.05.

RESULTS

PPV was conducted in 352 patients, among which 43.5% (n = 153) were in the P group and 55.6% (n = 196) were in the NP group. Both groups had significant BCVA improvement during the study period (p < 0.001), but with no significant difference between them. Anatomical success was similar between P (84.2%) and NP (87.2%) groups. No difference was found with regard to endotamponade (p = 0.07) or concomitant scleral band placement (p = 0.43). The NP group developed subsequent ERM more frequently (p = 0.004), but BCVA gains for eyes requiring repeat PPV for ERM were not found (p = 0.14).

CONCLUSIONS

Although ERM formation and greater anatomical success are reasons to support the use of ILM peeling in RRD, we did not observe any anatomical or functional difference regarding ILM peeling or functional gain with secondary ERM peeling.

Silicone oil removal after extended tamponade in proliferative diabetic retinopathy-a long range of follow-up

BACKGROUND

To investigate the anatomical and functional results of silicone oil (SO) removal after an extended period of SO tamponade in eyes having received vitrectomy for proliferative diabetic retinopathy (PDR).

METHODS

From May 2009 to August 2017, clinical records of patients who had vitrectomy for PDR and underwent SO removal were retrospectively reviewed. SO was in principle left in the eye for an extended period of time and would be removed promptly when complications relevant to SO rose, or at the same setting when other intraocular surgeries were performed. Main outcome measures include anatomical outcome, functional outcome, and postoperative complications.

RESULTS

Seventy-four eyes of 64 patients (31 males and 33 females) were analysed. The mean follow-up duration was 35.6 months (ranging from 6 to 99 months, median 32 months). The duration of SO tamponade ranged from 3 to 116 months (mean 26.89 months, median 16 months). Anatomical success was achieved in 95.9% at the last follow-up with best-corrected visual acuity (BCVA) becoming better or unchanged in 81.1%. Postoperative complications included ocular hypertension (>25 mmHg; > 4 weeks) in three eyes (4.1%), macular hole in two eyes (2.7%), transient choroidal detachment in one eye (1.4%), vitreous haemorrhage in four eyes (5.4%) and hyphaema in two eyes (2.7%).

CONCLUSIONS

The rate of retinal redetachment after an extended period of SO tamponade and removal was low and the majority of eyes obtained final visual acuity improvement. SO removal after an extended period of tamponade in PDR seems to be safe under proper indications and case selection.

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.

Effect of silicone oil on macular capillary vessel density and thickness

The present study assessed changes in macular capillary vessel density and thickness associated with ocular silicone oil tamponade (SOT) following complex vitreoretinal surgery. A total of 23 patients who underwent pars plana vitrectomy combined with intravitreal SOT were retrospectively enrolled, and a single eye was assessed in each participant. Furthermore, 20 patients who required silicone oil removal (SOR) were included. The macular capillary vessel density and the foveal avascular zone (FAZ) area were analyzed using optical coherence tomography angiography (OCTA) and retinal thickness was assessed by OCT. The results demonstrated that the macular capillary vessel density of the superficial capillary plexus (SCP) and deep capillary plexus (DCP), the FAZ area and full retinal thickness were retained at a stable level following SOT (P>0.05), and also following SOR (P>0.05). Furthermore, the parafoveal (P=0.008), superior-hemi (P=0.007), temporal (P=0.015), superior (P=0.028) and nasal (P=0.002) inner retinal thickness decreased in the SOT group, whereas the inner retinal thickness was unaltered after SOR vs. baseline (P>0.05). In conclusion, silicone oil has no significant effect on macular capillary vessel density within a 6-month period but may compress and reduce the thickness of the inner retina.

Factors of Retinal Re-detachment and Visual Outcome after Intraocular Silicone Oil Removal in Silicone Oil-filled Eyes

Background: This study aims to evaluate the risk factors of retinal re-detachment and visual outcome after silicone oil removal (SOR) in silicone oil-filled eyes.Methods: A total of 57 patients who underwent pars plana vitrectomy (PPV) and silicone oil injection for retinal detachment (RD), and subsequently underwent a silicone oil removal procedure. Pre-operative examinations were performed to determine the best-corrected visual acuity (BCVA) using the Snellen chart, while Icare was used to determine the intraocular pressure (IOP). In addition, slit-lamp examination of the anterior segment and lens, fundus pre-set lens examination for the posterior segment, color fundus photography, anterior segment photography and type B-ultrasonic scans were performed.Results: In five of 57 patients (8.77%), the retina re-detached following the removal of silicone oil. The factors for re-detachment were proliferative vitreoretinopathy (PVR) (two cases), the formation of new retinal breaks (two cases), and incomplete membrane peeling (one case). The rate of retinal re-detachment (reRD) was statistically independent of the duration of silicone oil endotamponade (P = .810). BCVA significantly improved following the removal of silicone oil (P = .001). The duration of the silicone oil tamponade was significant in the development of cataract (27 eyes, 47.3%; P = .0008), emulsified oil in the anterior chamber (13 eyes, 22.8%; P = .009), and glaucoma (seven eyes, 12.2%).Conclusion: The improvement of visual acuity was discovered following the removal of the intraocular silicone oil. Although the duration of the intraocular silicone oil endotamponade had no effect on the rate of retinal attachment, a longer duration of silicone oil endotamponade can lead to the development of complications, such as cataract, emulsified oil in the anterior chamber and glaucoma, suggesting that the earlier removal of oil should be performed.

A NOVEL FINDING OF HYPERREFLECTIVE MATERIAL IN THE SILICONE-RETINA INTERFACE: An Optical Coherence Tomographic and Histopathological Study

PURPOSE

To describe novel findings of hyperreflective material in the silicone-retina interphase on spectral domain optical coherence tomography (SD-OCT) imaging in eyes with silicone oil tamponade.

METHODS

Retrospective observational clinical study of consecutive patients who underwent primary pars plana vitrectomy with silicone oil tamponade for rhegmatogenous retinal detachment. Repeat clinical examination and spectral domain optical coherence tomography macular imaging performed 3 months after surgery were evaluated to identify any macular pathologies, including formation of epiretinal membranes, intraretinal changes, subretinal fluid, and edema before scheduled secondary vitrectomy for silicone oil removal.

RESULTS

Eighty-two patients (mean age 54 years, range 22-89) were included. Twelve eyes (14%) showed discrete preretinal hyperreflective organized coarse material in the silicone-retina interphase on spectral domain optical coherence tomography. The material was scattered in the posterior pole, with several foci showing additional hyperreflectivity of the inner retinal layers beneath. These findings did not resemble silicone oil emulsification in size, shape, or reflectivity.

CONCLUSION

This is the first report on hyperreflective material detected by spectral domain optical coherence tomography in the silicone-retina interphase in eyes with silicone oil tamponade. These findings may represent an inflammatory response to silicone oil exposure that may be the initial manifestation of a future proliferative process, warranting a rigorous follow-up protocol for affected patients.

Subretinal and Retrolaminar Migration of Intraocular Silicone Oil Detected on CT

BACKGROUND AND PURPOSE

Intraocular silicone oil injection has been used to treat complicated retinal detachments, and recently its retrolaminar and intracranial migration has been reported. The purpose of this study was to document the prevalence of posterior migration of intraocular silicone oil on head CT and describe the clinical and radiologic findings.

MATERIALS AND METHODS

This retrospective study included 57 patients with intraocular silicone oil injection who underwent unenhanced head CT between November 2008 and July 2018. All images were visually evaluated for subretinal and retrolaminar migration of intraocular silicone oil involving the anterior visual pathway (optic nerve, optic chiasm, and optic tract) and the ventricular system. Attenuation values of those structures were measured and compared with those of the contralateral or adjacent normal structures.

RESULTS

We detected subretinal and retrolaminar silicone oil migration in 7 of the 57 patients (12%), noting silicone oil at the optic nerve head (n = 2), retrolaminar optic nerve (n = 5), optic chiasm (n = 3), optic tract (n = 3), and in the lateral ventricles (n = 1). Attenuation values of the structures with silicone oil migration were significantly higher than those of the control regions (optic nerve head, 69.2 ± 12.4 vs 29.8 ± 10.2 HU, P < .001; retrolaminar optic nerve, 59.9 ± 11.6 vs 30.9 ± 8.6 HU, P < .001; optic chiasm, 74.2 ± 11.0 vs 25.6 ± 6.9 HU, P < .001; optic tract, 70.1 ± 4.7 vs 28.7 ± 7.2 HU, P < .001). No significant ophthalmic or neurologic complications were documented in the patients with silicone oil migration.

CONCLUSIONS

Subretinal and retrolaminar migration of intraocular silicone oil is common. Although there were no apparent complications associated with silicone oil migration, the radiologist and clinician should be aware of this phenomenon.

Silicone oil removal: post-operative complications

PURPOSE

To describe the characteristics, outcomes and complications of eyes after silicone oil removal.

METHODS

Retrospective case series of eyes that underwent oil removal between 2012 and 2016 at The Institute of Ophthalmology and Visual Science. Visual acuity (VA), intraocular pressure (IOP) and rates of retinal re-detachment, hypotony, ocular hypertension, corneal decompensation, cystoid macular edema (CME) and cataract progression were evaluated.

RESULTS

Totally, 101 eyes of 99 patients (65% male, average age 47.2 years) were identified. Oil tamponade had been used for retinal detachment (RD) repair in all eyes; 15 eyes had also undergone an open globe repair previously. The most common vitreous substitutes used after oil removal were balanced salt solution (BSS) and air in 90% of eyes. The average time of oil tamponade before removal was 9.46 months. The average logMAR VA before oil removal was 1.7 which improved to an average of 1.4 post-operatively. The average IOP pre-operatively was 16.1 mm Hg, which decreased to an average of 14.8 mm Hg post-operatively. Complications after oil removal, included retinal re-detachment (6.9%), hypotony (7.9%), ocular hypertension (12.9%), corneal decompensation (9.9%), CME (2%) and cataract progression (68%).

CONCLUSION

This study showed an overall improvement in VA and decrease in IOP after oil removal. Cataract progression was the most common complication.

Improved Outcomes in Patients with Retinal Detachment after Implementation of a Silicone Oil Registry and Phone Call Reminder System

PURPOSE

This retrospective study was performed to assess the clinical impact in reducing silicone oil (SO)-related complications such as keratopathy of a registry and appointment reminder system for patients with complicated retinal detachment (RD) who underwent pars plana vitrectomy (PPV) with SO tamponade.

DESIGN

Retrospective cohort study.

PARTICIPANTS

A total of 87 eyes of 87 patients who received SO tamponade were included.

METHODS

The study was carried out at Zuckerberg San Francisco General Hospital and Trauma Center (ZSFG). Patients were divided into those who received SO before (control group, n = 48) or after (treatment group, n = 39) implementation of an SO registry and patient reminder system in 2014. Patient records were reviewed to identify clinical characteristics and outcomes.

MAIN OUTCOME MEASURES

The primary outcome measure was the difference in the rate of loss to follow-up before versus after the implementation of the registry and reminder system. Secondary outcomes were the duration of SO tamponade, keratopathy rate, and intraocular pressure (IOP) at the last visit before SO removal.

RESULTS

Forty-eight patients were included in the control group, and 39 patients were included in the treatment group. The number of patients lost to follow-up was 23 (47.9%) in the control group versus 6 (15.4%) in the treatment group (P = 0.0015). The mean duration before SO removal was 79.6±91.7 weeks in the control group and 36.3±31.5 weeks in the treatment group (mean±standard deviation [SD]) (P = 0.015). Keratopathy developed in 33.3% of patients in the control group and 12.8% of patients in the treatment group (P = 0.0425). Mean IOP at the last visit before SO removal was 13.0±5.2 mmHg (mean±SD) in the control group and 13.3±7 mmHg (mean±SD) in the treatment group (P > 0.05).

CONCLUSIONS

A phone call appointment reminder system for patients with complicated RD who underwent PPV and SO tamponade reduced the rate of loss to follow-up and the duration of SO tamponade, correlating with a reduction in the rate of keratopathy.