Heavy silicone oil and intraocular inflammation

Pars Plana Vitrectomy With Silicone Oil or Gas Tamponade for Uncomplicated Retinal Detachment: A Systematic Review and Meta-Analysis

PURPOSE

To compare the efficacy and safety of pars plana vitrectomy (PPV) with silicone oil compared to gas tamponade for uncomplicated rhegmatogenous retinal detachment (RRD).

DESIGN

Systematic review and meta-analysis.

METHODS

A systematic literature search was conducted on Ovid MEDLINE, Embase, and the Cochrane Library from January 2000 to September 2023 for comparative studies evaluating the efficacy and safety of PPV with either silicone oil or gas tamponade in the setting of uncomplicated RRD. Our primary outcome was best-corrected visual acuity at the last study observation. Secondary outcomes included the rates of retinal reattachment, retinal thickness, and the incidence of adverse events. We performed a meta-analysis using a random-effects model.

RESULTS

Nine observational studies reporting on 491 RRD eyes were included. The mean best-corrected visual acuity at the last study observation was significantly better in the gas tamponade group than in the silicone oil group (weighted mean difference [WMD] = 0.17 logMAR, 95% confidence interval [CI] = [0.06, 0.27], P = .002). Rates of primary retinal reattachment were similar between the silicone oil and gas tamponade groups (P = .89). The ganglion cell layer was significantly thinner in the silicone oil group compared to the gas tamponade group (WMD =-3.70 µm, 95% CI = [-5.87, -1.53, P = .0008), as was the inner plexiform layer (WMD = -2.45, 95% CI = [-4.50, -0.40], P = .02) and outer nuclear layer (WMD = -11.74 µm, 95% CI = [-18.39, -5.10], P = .0005).

CONCLUSIONS

PPV with gas tamponade was associated with better functional outcomes compared to PPV with silicone oil, although both tamponades yielded comparable primary reattachment rates. The absence of randomized trials and the potential for selection bias underscore the importance of further investigation in diverse patient populations.

Retrospective case series of high-density silicone oil (Oxane HD) in severe proliferative vitreorretinal retinal detachment patients

BACKGROUND

Describe complications and clinical outcomes of heavy silicone oil (HSO) Oxane HD® use as an alternative to overcome the challenges of performing vitrectomy to treat tractional and rhegmatogenous retinal detachments with proliferative vitreoretinopathy (PVR).

METHODS

A retrospective, observational study was performed on patients from one center from August 2014 to Aug 2023. It was included patients who underwent surgery using HSO Oxane HD® to treat rhegmatogenous retinal detachment with PVR or mixed tractional and rhegmatogenous diabetic retinal detachment. Severely ill patients who could not attend to follow up were excluded. The primary outcome was successful retinal attachment at first postoperative month. A descriptive analysis was performed.

RESULTS

Among the 31 patients, 29 (93.5%) underwent surgeries due to rhegmatogenous retinal detachment and two (6.5%) for diabetic retinal detachment. The primary anatomic success was achieved in 27 (87.1%) patients. At the final visit, 17 (56.6%) had vision better than 20/400 (range, 20/30 to light perception). The vision was stable or improved in 22 (76.8%) patients at the end of follow-up. Nineteen (61.3%) patients required hypotensive eye drops after HSO use and twelve (38.7%) still required hypotensive eye drops at the final follow-up; three (9.7%) patients required additional glaucoma surgeries.

CONCLUSIONS

HSO is safe and useful for complex retinal detachments cases specially with inferior tears and PVR. Ocular hypertension is frequent and usually clinically controlled with hypotensive eyedrops. Close postoperatively follow-up is advised due to the ocular complications, particularly elevated intraocular pressure and emulsification.

Silicone oil tamponade induced vasculitis- a rare manifestation of toxic posterior segment syndrome

AIM

To report silicone oil tamponade induced vasculitis in the early post operative period - a rare manifestation of 'Toxic Posterior Segment Syndrome' after pars plana vitrectomy for rhegmatogenous retinal detachment.

CASE DESCRIPTION

A 50-year-old gentleman presented with vasculitis after a pars plana vitrectomy with silicone oil tamponade on the first post-operative day. He was started on oral steroids (1 mg/ kg) tapered sequentially every week. All signs of vasculitis resolved over a period of one month after which the silicone oil was removed. The patient maintained a visual acuity of 20/90 even after 3 months. There was no recurrence of vasculitis observed thereafter.

CONCLUSION

Silicone oil induced vasculitis is a rarely described entity, especially as a manifestation of toxic posterior segment syndrome. This differential must be kept in mind even on the first post-operative day in cases where silicone oil has been used for tamponade.

Unexplained visual loss in retinal detachment repair: comparing gas, silicone oil and heavy silicone oil by multivariable regression

PURPOSE

To measure the proportion of unexplained and all causes of visual loss following primary rhegmatogenous-retinal-detachment (RRD) repair, comparing gas tamponade (SF₆, C₂F₆, C₃F₈), silicone oil (SO, 1000cs and 5000cs) and heavy silicone oil (Densiron).

METHODS

Retrospective, continuous, comparative study from 01/1/2017-31/5/2021. All primary RRDs were included after successful removal of SO and Densiron. Primary failures were excluded. Visual loss was defined as reduction of ≥0.30 logMAR units. Multivariable binary-logistic and linear regression models to compare tamponade, and all cases of unexplained visual loss and logMAR gain were performed. Covariates included age, ocular co-morbidities, pre-op vision, macula-status, high-myopia, giant-retinal-tear (GRT), perfluorocarbon-use, combined buckle/PPV, PVR-C, retinectomy, tamponade agent and post-operative lens status.

RESULTS

Of 1,012 primary RRDs, we found an incidence of unexplained visual loss in 15/1012 (1.5%, SF₆:1/341[0.3%], C₂F₆:4/338[1.2%], C₃F₈:2/239[0.8%], Densiron:0/33[0.0%], SO-1000cs:5/43[11.6%] and SO-5000cs:3/18[16.7%]), and visual loss of all causes in 57/1012 (5.6%, SF₆:13/341[3.8%], C₂F₆:14/338[4.1%], C₃F₈:15/239[6.3%], Densiron:2/33[6.1%], SO-1000cs:9/43[20.9%] and SO-5000cs:4/18[22.2%]). On multivariable binary-logistic regression, we report that macula-on RRD (Odds-Ratio[OR]5.7,95% Confidence-interval[CI]1.2-28.2, p=0.032), GRT (OR35.0,CI 2.0-617.3, p=0.015), combined buckle/PPV (OR37.7,CI 2.0-711.4, p=0.015), SO1000cs (OR86.6,CI 5.6-1,348.0), p=0.001) and 5000cs (OR37.2,CI 1.3-1,101.5, p=0.036) (Reference-tamponade:SF₆) were associated with unexplained visual loss. Duration of oil tamponade was not linked to increase in unexplained visual loss (p=0.569).

CONCLUSIONS

Correlation between SO in detachment repairs and unexplained visual loss has been established, however incidence with HSO has not been compared to other agents. This study demonstrates that although SO was linked with risk-adjusted increased unexplained visual loss relative to gas tamponade, no such association was found for Densiron, on multivariable analysis.

Retinal Nerve Fiber Layer Changes after Intraocular Silicone Oil Tamponade in Rhegmatogenous Retinal Detachment

Rhegmatogenous retinal detachment (RRD) is a serious and emergency condition that may cause visual disturbance. Treatment includes pars plana vitrectomy with a tamponade such as intraocular gas or silicone oil (SO). In many countries, silicone oil is still favorable compared to intraocular gases as tamponade for reattachment of retinal detachment surgery. The application provides a higher anatomical success rate, especially in cases of proliferative vitreoretinopathy (PVR) that were previously considered untreatable. Objective assessment of the retinal nerve fiber layer (RNFL) using optical coherence tomography (OCT) in the eye with silicone oil tamponade is a challenge because of the limitations and difficulties in taking images. This study aims to assess the RNFL thickness changes in rhegmatogenous retinal detachment patients using SO tamponade and its subsequent removal conducted on a total of 35 post-operative RRD patients. Central macular and RNFL thickness, as well as best-corrected visual acuity (BCVA), were recorded at the time of tamponade and after the removal of the SO at 1, 4, and 8 weeks, respectively. The results showed that the changes in RNFL thickness significantly decreased in the group of ≤6 months, especially in the superior and temporal quadrants, and BCVA increased after SO removal (p < 0.05). Central macular thickness was significant (p < 0.001) at the end of the visit. Improved visual acuity is associated with decreased RNFL and central macular thickness after SO removal.

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.

Vitreous Substitutes from Bench to the Operating Room in a Translational Approach: Review and Future Endeavors in Vitreoretinal Surgery

Vitreous substitutes are indispensable tools in vitreoretinal surgery. The two crucial functions of these substitutes are their ability to displace intravitreal fluid from the retinal surface and to allow the retina to adhere to the retinal pigment epithelium. Today, vitreoretinal surgeons can choose among a plethora of vitreous tamponades, and the tamponade of choice might be difficult to determine in the ever-expanding range of possibilities for a favorable outcome. The currently available vitreous substitutes have disadvantages that need to be addressed to improve the surgical outcome achievable today. Herein, the fundamental physical and chemical proprieties of all vitreous substitutes are reported, and their use and clinical applications are described alongside some surgical techniques of intra-operative manipulation. The major upcoming developments in vitreous substitutes are extensively discussed, keeping a translational perspective throughout. Conclusions on future perspectives are derived through an in-depth analysis of what is lacking today in terms of desired outcomes and biomaterials technology.

Main Principles of Vitrectomy Using Intraocular Tamponades - A Basic Course in Surgery

This article is intended to clearly present the basic principles for the use of intraocular tamponades in vitreous/retinal surgery in the event of retinal detachment and other pathologies using additional video footage. It examines the various gases, silicone oils and perfluorocarbon liquids with their indications, administration and in particular intraoperative handling including pitfalls and complications. Characteristic animations show the principles of use in surgery in a comprehensible way. The two lead authors dedicate this article to their teacher Prof. Dr. V.-P. Gabel, who in the early 1990s successfully established the first vitrectomy courses for ophthalmologists at Regensburg University Eye Clinic each year. Many colleagues who still work in retinal surgery today first started learning about this segment on these courses. The other coauthors participated under his supervision in annual vitrectomy wet labs run by the German Academy of Ophthalmology.

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.

Editorial: Imaging in Ophthalmology

Over the last decade, ophthalmology has significantly benefited from advances in vivo non-invasive ophthalmic imaging techniques that play currently a fundamental role in the clinical assessment, diagnosis, management, and monitoring of a wide variety of conditions involving both the anterior and posterior segment [...]

Retinal and Corneal Changes Associated with Intraocular Silicone Oil Tamponade

Silicone oils (SO) are used as long-term intraocular tamponades and have an irreplaceable role in vitreoretinal surgery. They can, however, be associated with multiple and potentially severe complications, involving different ocular tissues, in particular retina and cornea. Recent advances in ophthalmic imaging have allowed the precise characterization of retinal and corneal microstructural changes, at a subclinical level. This detailed analysis of SO-related retinal and corneal changes has improved our understanding of their pathogenesis and offer the potential for optimized monitoring and management of patients with SO-filled eyes. This review aims to provide clinicians and ophthalmic scientists with an updated and comprehensive overview of the corneal and retinal changes associated with SO tamponade.

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.

[Visual acuity reduction and silicone oil tamponade]

Silicone oil is an established intraocular surgical aid, which enables the treatment of the most complex starting situations but no other alternative has been found; however, the available data indicate that an unclear loss of visual acuity during or after an intraocular silicone oil tamponade possibly occurs more frequently than assumed from the clinical routine. Various pathological mechanisms are under discussion as causes, but the exact causes are actually unclear. In addition to atrophic alterations in the optical coherence tomography (OCT) examination, there are a clear reduction in visual acuity and mostly a central scotoma with otherwise inconspicuous findings. Unclear loss of visual acuity can also occur after removal of the silicone oil. Whether this is caused by the same pathological mechanism is unclear. Furthermore, there are no reproducible risk factors that appear a priori to possibly cause an unclear loss of vision under silicone oil; however, oil removal as soon as possible and a good adjustment of the intraocular pressure are recommended by the authors. Overall, a silicone oil tamponade should be carefully weighed up even when using modern highly purified silicone oils and it should therefore continue to be reserved particularly for unfavorable initial situations or complicated courses with the necessity for a silicone oil tamponade. Against this background, a study for systematic recording and processing of cases of unclear loss of visual acuity after silicone oil tamponade seems to be meaningful.

Evaluation of long-term outcomes associated with extended heavy-silicone oil use for the treatment of inferior retinal detachment

To evaluate macular status with optical coherence tomography (OCT) in eyes that underwent pars plana vitrectomy (PPV) and heavy-silicone oil (HSO) endotamponade for the treatment of rhegmatogenous retinal detachment (RRD) with inferior breaks. Twenty eyes of 20 patients who have RRD with inferior breaks included in the study. Oxane HD was used as an intraocular tamponade for all surgeries. Postoperatively, anatomic reattachment, macular status using OCT imaging, and any long-term complications were evaluated. The mean age was 60.4 ± 11.2 years (range, 37-83). The duration of HSO endotamponade was 15.3 ± 11.0 months (range, 6-48) with some postoperative complications such as HSO emulsification, intraocular pressure elevation, and epiretinal membrane (ERM) formation. Mean follow-up time was 19.5 ± 10.5 months (range, 10-59) after HSO removal or ERM surgery. Primary reattachment was achieved in 90% of eyes and the success rate was 100% with further interventions. Ellipsoid zone (EZ) was continuous in 13 of 20 eyes in which OCT imaging performed as well as the fellow eye. PPV and heavy-silicone oil injection for the treatment of eyes with RRD from inferior break(s) have a good long-term EZ continuity. ERM formation and its removal do not affect EZ.

Heavy Silicone Oil as an Endotamponade in Recurrent or Complicated Retinal Detachment and Macular Hole

Objectives:

To evaluate the efficacy and safety of heavy silicone oil as an endotamponade in patients with recurrent or complicated retinal detachment and macular hole.

Materials and Methods:

Nineteen eyes of 19 patients who underwent heavy silicone oil endotamponade for different indications were included in the study and evaluated by retrospective chart review. At each visit, patients underwent detailed ophthalmological examination and anatomical and functional outcomes, silicone oil emulsification, intraocular inflammation, presence of proliferative vitreoretinopathy, preoperative and postoperative visual acuity, and postoperative complications were recorded.

Results:

The study included 19 eyes of 19 consecutive patients: 13 women (68.4%) and 6 men (31.6%). The patients’ median age was 60 years (interquartile range [IQR]: 44-70 years) and the median follow-up time was 19 months (IQR: 9-31 months). Indications for heavy silicone oil endotamponade were recurrent retinal detachment in 11 eyes (57.8%), inferior retinal detachment in 5 eyes (26.3%), inferior rhegmatogenous retinal detachment, recurrent macular hole in 2 patients (10.5%), and macular hole in 1 patient (5.2%). Median best corrected visual acuity was 2 logMAR (IQR: 1-2.6) preoperatively and 0.99 logMAR (IQR: 0.4-2) postoperatively (p<0.001). Postoperative anatomical success was achieved in all patients. Densiron 68 was used for endotamponade in 14 patients (73.7%), Densiron XTRA in 3 patients (15.8%), and AlaHeavy 1.07 in 2 patients. Heavy silicone oil emulsification was observed in only 3 patients (15.8%).

Conclusion:

Although heavy silicone oil has limitations as an endotamponade, such as intraocular pressure increase, emulsification, intraocular inflammation, and the risk of complications during removal, it is a safe and effective alternative in eyes requiring inferior retinal tamponade for indications like proliferative vitreoretinopathy and recurrent macular holes.

Factors affecting retinal re-detachment following silicone oil removal for rhegmatogenous retinal detachments

PURPOSE

To report factors affecting retinal re-detachment rate after silicone oil removal (SOR) following rhegmatogenous retinal detachment (RRD) repair.

METHODS

Retrospective cohort study from December 1, 2014 to March 1, 2020 of 205 consecutive patients treated for RRD with SO tamponade and subsequent SOR with at least 6 months follow-up. Primary outcome measure was rate of retinal re-detachment following SOR.

RESULTS

The retinal re-detachment rate following SOR was 18.5%. Preoperative macula and lens status, PVR, previous retinectomy, RD size, concomitant phacoemulsification, previous scleral buckling, and endolaser during SOR did not affect re-detachment rate after SOR. Previous SO exchange was associated with increased re-detachment (OR 2.53, 95% CI (1.11 - 5.80), p = 0.0278). 12 months of SO tamponade had lower re-detachment rates compared to 3 months (OR 0.25, 95% CI [0.04 - 0.09], p = 0.048). Shorter SO tamponade (3 vs. 12 months) had better final visual outcomes after SOR (0.80 ± 0.61 vs 1.41 ± 0.66, p <0.0001).

CONCLUSIONS

No preoperative or intraoperative factors in this analysis influenced the risk of re-detachment following SOR except duration of SO tamponade and previous SO exchange. While longer SO tamponade duration may be associated with lower rates of re-detachment, visual outcomes may be worse.

Silicone oil complications in vitreoretinal surgery

Objective: To illustrate the complications in subjects who experienced posterior vitrectomy and internal tamponade with silicone oil. Design: Prospective, observational, longitudinal, descriptive, series of cases. Material and methods: Patients who underwent posterior vitrectomy and internal tamponade with silicone oil of 1000 centistokes, from April to October 2021, were considered. All subjects included in the study had a complete ophthalmic examination pre and postoperatively on first day, first week and 1 to 6 months, and were assessed the best corrected visual acuity, ocular tension (raised > 21 mmHg, hypotony < 5 mmHg), emulsification, keratopathy, cataracts and posterior pole. Results: 40 eyes of 40 patients were considered; twenty women and 20 men, with an average age of 63 years (range 46 to 77 years). Conclusions: Complications are brief, treated medically or surgically, with better prognosis.

OPTICAL COHERENCE TOMOGRAPHIC PATTERNS OF POSTERIOR SEGMENT STICKY HEAVY SILICONE OIL

PURPOSE

To describe unique optical coherence tomography observations of adherent preretinal heavy silicone oil after removal.

METHODS

Retrospective observational review of files and optical coherence tomography scans of patients who had pars plana vitrectomy with heavy silicone oil. We investigated the possible precipitating preoperative and intraoperative factors and the association with postoperative epiretinal membrane and cystoid macular edema.

RESULTS

Forty-one eyes from 39 patients were involved. Two characteristic sticky silicone oil structures were identified in 33 patients (80%): variably reflective macrodroplets (bubbles) and hyperreflective microdroplets (dots). The main contributing variable was the tamponade duration. Other notable associations included postoperative epiretinal membrane and cystoid macular edema formation. Surgical interventions including heavy liquid did not show a strong predilection to their development. We reported two novel findings of sticky prefoveal macrodroplets in five patients and intravitreal macrodroplets and microdroplets casting shadows on the underlying retina in four patients.

CONCLUSION

This study confirms previously reported optical coherence tomography observations of sticky emulsified silicone oil remnants after removal. This is the first report of two distinctly different optical coherence tomography appearances after heavy silicone oil removal. The variability in size and reflectivity may be attributed to the amount and nature of the induced inflammatory reaction.

Toxic Posterior Segment Syndrome Presenting as Occlusive Retinal Vasculitis following Vitreoretinal Surgery

Purpose

To report a rare retinal manifestation of toxic posterior segment syndrome following vitreoretinal surgery.

Methods

In this case series, we report three cases of rhegmatogenous retinal detachment for which pars plana vitrectomy with silicone oil injection was done. All three patients developed an intense anterior chamber reaction along with occlusive vasculitis-like fundus picture.

Results

The three patients were started on topical and systemic steroids, and there was a dramatic improvement in vision and clinical signs at postoperative week 1.

Conclusion

Toxic posterior segment syndrome is a sight-threatening complication after vitreoretinal surgery, but responds well to topical and systemic steroids.

Biocompatibility of intraocular liquid tamponade agents: an update

Intraocular liquids tamponade agents, such as perfluorocarbon liquids (PFCLs), semifluorinated alkanes (SFAs), silicone oils (SOs) and heavy silicone oils (HSOs), are a crucial intraoperative and/or postoperative tool in vitreoretinal surgery, in particular for the management of complex vitreoretinal diseases. However, their use is not without complications, which are potentially severe. Consequently, a growing interest has been devoted to the biocompatibility of these compounds and the adequacy of current regulations that should guarantee their safety. Obviously, an updated knowledge on research findings and potential risks associated to the use of intraocular liquid compounds is essential, not only for vitreoretinal surgeons, but also for any ophthalmologist involved in the management of patients receiving intraocular liquid tamponades. In light of this, the review provides a comprehensive characterisation of intraocular liquid tamponades, in terms of physical and chemical properties, current clinical use and possible complications. Moreover, this review focuses on the safety profile of these compounds, summarising the existing regulation and the available evidence on their biocompatibility.

Medical management of silicone oil associated acute postoperative ocular inflammation

We report a case of a 57-year-old man, who underwent right eye silicone oil injection as a part of his surgical treatment for rhegmatogenous retinal detachment. Following this, on the first postoperative day, he developed acute postoperative intraocular inflammation. There was circumciliary congestion, diffuse corneal oedema, anterior chamber (AC) reaction, hypopyon and a pupillary membrane. The AC had not been entered during the surgery. No patients, who had been operated on the same day, or with the materials having the same batch number, developed similar reactions. We started the patient on hourly topical steroids and cycloplegics after which the patient's condition showed gradual improvement. At the 2 weeks follow-up appointment, his pupillary membrane had completely contracted and the AC was quiet. This case highlights a clinical picture of acute postoperative silicone oil-induced ocular inflammation, which was resolved through medical management.

Silicone oil-associated orbital cellulitis with lipogranulomatous inflammation in the setting of HIV: a management challenge and clinicopathological correlation

A 58-year-old Indian man presented with pain and redness of the left eye (OS) for one day. Patient had undergone silicone oil removal in OS for emulsified oil following vitrectomy and oil tamponade six months ago when he was diagnosed with retinal detachment in both eyes due to HIV retinopathy. Retinal detachment in the right eye (OD) was inoperable and had turned prephthisical at presentation, while his vision in OS was finger counting. Intraocular pressure in OD was 8 mm Hg and unrecordably elevated in OS. Extraocular movements were limited by periorbital oedema and proptosis. Slit-lamp examination revealed corneal haze, cells 2+/flare 1+ with pseudophakia, and attached retina. Histopathology showed lipogranulomatous inflammation, hitherto unreported in association with silicone oil. The index case posed a management challenge since his only functional eye had potentially been compromised by glaucoma and orbital cellulitis with compartment syndrome, against the backdrop of an immunocompromised status.

The Role of Endogenous Proteins on the Emulsification of Silicone Oils Used in Vitreoretinal Surgery

The present work is aimed at investigating the chemicophysical properties of the interface between silicone oils (SOs) used in vitreoretinal surgery and aqueous solutions, in the presence of surfactant biomolecules. Such molecules are thought to play an important role in the formation of SO emulsions in vitrectomised eyes, in which the natural vitreous body has been replaced with a SO. In particular, we have measured the interfacial tension (IT) and the interfacial dilational viscoelasticity (DV) of the interface between SO (Siluron 1000) and serum proteins (albumin and γ-globulins) at various concentrations in a Dulbecco alkaline buffer. The equilibrium IT value is relevant for the onset of emulsification, and the DV influences the stability of an emulsion, once formed. The study is complemented by preliminary emulsification tests. The experimental results show that, when proteins are dissolved in the aqueous solution, the rheological properties of the interface change. The IT decreases significantly for physiological protein concentrations, and the DV modulus achieves high values, even for small protein concentrations. The emulsification tests confirm that, in the presence of proteins, emulsions are stable on the time scale of months. We conclude that the measured values of IT in the presence of serum proteins are compatible with the promotion of droplet formation, which, in addition, are expected to be stable against coalescence. Adsorption of biomolecules at the interface with the SO is, therefore, likely to play an important role in the generation of an emulsion in eyes subjected to vitrectomy. These findings are relevant to identify strategies to avoid or control the formation of emulsions in eyes.

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.

Emulsified silicone oil is taken up by and induces pro-inflammatory response in primary retinal microglia

Purpose

Silicone oil is used as endotamponade in combination with vitrectomy. Thinning of retinal layers and loss of retinal cells under silicone oil use have been found. Here, we investigate the influence of silicone oil on primary microglia cells.

Methods

Primary microglia cells were prepared from the porcine retina. Microglia identity was assessed with Iba1 staining. Silicone oil was emulsified by sonification. Cell morphology and silicone oil uptake were evaluated by light microscopy after Coomassie blue staining. Cytokine secretion was evaluated with ELISA. Toxicity of silicone oil on microglia and toxic effect of silicone oil–treated microglia on neuronal cell line PC12 were evaluated by MTT or WST assay, respectively.

Results

Microglia took up silicone oil droplets after 72 h of incubation. Silicone oil induced no toxicity but increased the metabolism in microglial cells. In addition, the secretion of IL-6 and IL-8, but not of IL-1ß or TNF-α, was induced. Silicone oil–treated microglia did not exert any neurotoxic effect on differentiated PC12 cells but induced an increase in metabolism.

Conclusion

Emulsified silicone oil changes the activity level of microglia and induces the secretion of IL-6 and IL-8. Neurotoxicity is not induced. Further experiments are required to investigate the long-term effect of silicone oil on microglia and their consequent effect on neuronal cells.

Watch out for the special location of intraventricular silicone oil following an intraocular tamponade - a 10-year follow-up case report based on CT/MRI

Background

Intraventricular silicone oil is a relatively rare complication resulted from silicone oil tamponade to treat retinal detachment. It is occasionally reported in previous literature. To the best of our knowledge, the long-term longitudinal comparisons of silicone oil both in the brain and in the postoperative eyeball based on CT/MRI were lacking, and intraventricular silicone oil accumulation beside lesions has been reported rarely.

Case presentation

A 63-year-old male patient underwent an intraocular tamponade with silicone oil in June 2009. Eight CT examinations and 2 MRI examinations were acquired between 2011 and 2018.The changes of silicone oil in the brain in CT/MRI as below: Silicone oil initially migration to bilateral lateral ventricular anterior horn was found in November 2011, it was aslo found at right side of suprasellar cisterna, and there was no change in location 6 h later; Silicone oil at the anterior horn of right lateral ventricle disappeared but remained at left lateral ventricle and right side of suprasellar cisterna in July 2014, and there was no change in location in a short-term reexamination. It was found at the middle of left lateral ventricle (adjacent to the real cause) in march 2018, but disappeared 3 months later, while remained at anterior horn of left lateral ventricular and right side of suprasellar cisterna all the time. There was no change in location in the next 2 follow-up (September and October in 2018). The CT values of silicone oil distributed throughout the brain were dynamically changed with time.

Conclusion

It is important to recognize intraventricular silicone oil in a particular location.More important is to discover “the real murderer”, which is the main cause of symptoms in the vicinity of special location. Moreover, the migration of silicone oil between eyeball and brain may not be always in a single direction.

Comparative Study of Chemical Composition, Molecular and Rheological Properties of Silicone Oil Medical Devices

Purpose

We evaluated chemical composition, and molecular and rheological properties in 10 commercially available silicone oils (SilOils), focusing on siloxane chains of low molecular weight (LMW components, LMWC) that are known to be “impurities” produced during the SilOil synthesis process.

Methods

We assessed the type of SilOil polymer and molecular weight distribution (MWD) by spectroscopy and conventional size exclusion chromatography, respectively. From the Cumulative MWD, we calculated the fractions of LMWC with molecular weight (M): ≤2000, ≤5000, and ≤10,000 g/mol. Due to the low MW, the content of LMWC with M ≤1000 g/mol was determined by gas chromatography-mass spectrometry. The dynamic viscosity (η) was assessed by rotational rheometry.

Results

For all SilOils, the polymer was polydimethylsiloxane. The samples differed significantly in terms of MWD and relative LMWC fractions. Specifically, the relative fraction of all LMWC (M ≤10,000 g/mol) ranged from 2.31% to 9.40% and the content of LMWC with M ≤1000 g/mol also varied significantly (range, 51–1151 ppm). The η values were different between the SilOils, and, for many of them, from the declared viscosity.

Conclusions

Commercially available SilOils differ significantly in molecular and rheologic features. These compounds contain a significant amount of LMWC, “impurities” generated during the synthesis process, acting as emulsifier, potentially inducing ocular inflammation and toxicity.

Translational Relevance

The amount of impurities in different SilOils may influence significantly their biocompatibility.

Management of recurrent rhegmatogenous retinal detachment

Rhegmatogenous retinal detachment (RRD) repair is one of the most common vitreoretinal surgeries a surgeon performs. In an ideal scenario, RRD can be repaired with a single surgical intervention; however, despite excellent skill, flawless technique, and the introduction of high-end technology, up to 10% of cases require additional interventions to ultimately repair recurrent detachments. It is thus important to study the outcomes of multiple interventions to understand whether performing repeat vitrectomy on patients with a history of failed surgeries is worthwhile. Thus, recurrent retinal detachment (re-RD) remains a significant challenge for vitreoretinal surgeons as well as the patients considering the economic and the emotional burden of undergoing multiple interventions. The advent of microincision vitrectomy system, perfluorocarbon liquids, and effective intraocular tamponades has opened new doors for managing re-RDs. In this article, we have reviewed and summarized the various causes and approaches for management for optimal anatomical and functional outcomes.

Comparative assessment of intraocular inflammation following standard or heavy silicone oil tamponade: a prospective study

PURPOSE

To evaluate the inflammation associated with the use of standard silicone oil (polydimethylsiloxane; PDMS) and heavy silicone oil (HSO) Densiron-68™ in patients undergoing vitrectomy for retinal detachment.

MATERIALS AND METHODS

A prospective study was performed involving 35 patients scheduled to undergo vitrectomy for retinal detachment. Patients received PDMS or Densiron-68™ HSO according to superior or inferior retinal localization of the tears, respectively. For assessing the inflammation, prostaglandin E2 (PGE₂ ) and interleukin-1α (IL-1α) levels were evaluated in the aqueous.

RESULTS

Thirty-five eyes of 35 patients completed the study: 20 eyes received HSO, and 15 eyes received PDMS. The mean aqueous PGE₂ level was significantly higher in HSO patients than in PDMS patients (869.16 ± 242.83 pg/ml versus 369.38 ± 209.7 pg/ml, respectively; p < 0.0001). The mean aqueous IL-1α level was also significantly higher in HSO patients than in PDMS patients (81.40 ± 36.9 pg/ml versus 40.8 ± 32.5 pg/ml, respectively; p = 0.002). In HSO, a moderate positive correlation between the endotamponade duration and both PGE₂ (r = 0.44; p = 0.05) and IL-1α (r = 0.48; p = 0.033) levels was observed. In PDMS, a strong positive correlation between the endotamponade duration and both PGE₂ (r = 0.89; p < 0.0001) and IL-1α (r = 0.68; p = 0.006) levels was observed.

CONCLUSION

Although both HSO and PDMS yielded favourable success rates in the surgical treatment of complicated retinal detachments, HSO triggered a more severe inflammatory reaction, in a time-dependent manner.

THE CURRENT SURGICAL MANAGEMENT OF LARGE, RECURRENT, OR PERSISTENT MACULAR HOLES

PURPOSE

To evaluate the current surgical options available for the management of large (>400 μm), recurrent, or persistent macular holes (MHs).

METHODS

A review of the literature was performed, focusing on the epidemiology, pathophysiology, diagnosis, and surgical treatments of large, recurrent, or persistent MHs. Based on this review, a comprehensive overview was provided regarding the topic of large, recurrent, or persistent MHs and focused on recent surgical management updates.

RESULTS

For large MHs, variations of the inverted internal limiting membrane flap technique demonstrated promising rates of primary hole closure and significant visual acuity improvements. For recurrent or recalcitrant MHs, early repeat vitrectomy with extension of the internal limiting membrane peel remains the most straightforward and optimal surgical technique to achieve secondary closure. Regardless of the surgical approach, the goal of each technique described is to induce or aid in stimulating gliosis within the MH to maximize closure.

CONCLUSION

Despite the high success rate of modern MH surgery, large, recurrent, or persistent MHs remain a challenge for retinal surgeons. This review provides a detailed summary on the rationality and efficacy of current surgical options.

Rapid macular hole formation and closure in a vitrectomized eye following rhegmatogenous retinal detachment repair

The development of a full-thickness macular hole (FTMH) after pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment (RRD) repair is a rare occurrence. We report the first case of rapid MH formation with internal limiting membrane (ILM)-like hyper-reflective bridging membrane under silicone oil (SO) meniscus, noted on the first postoperative day (POD) postvitrectomy for RRD. A 57-year-old man presented with best-corrected visual acuity (BCVA) of perception of light with immature cataract and total RRD in the left eye. He underwent cataract extraction with intraocular lens implantation with uneventful PPV, endolaser to primary break, and 360° periphery followed by injection of 1000 Cst SO. On the first POD, retina was attached in all quadrants with SO in situ. However, a dark red spot was noted at macula which was confirmed as FTMH with a bridging linear hyper-reflectivity under SO meniscus on optical coherence tomography (OCT). Repeat OCT, at 2 weeks and 3 months, revealed closed MH under the SO meniscus with BCVA improving to 6/60. This is the first reported case of very rapid FTMH formation with an ILM-like linear hyper-reflectivity following vitrectomy for RRD and highlights the possible contributory role of multiple nonconventional factors for rapid FTMH development and fibrinous membrane-assisted closure under SO tamponade.

Vitreous Substitutes: Old and New Materials in Vitreoretinal Surgery

Recent developments in vitreoretinal surgery have increased the need for suitable vitreous substitutes. A successful substitute should maintain all the physical and biochemical properties of the original vitreous, be easy to manipulate, and be long lasting. Substitutes can be gaseous or liquid, both of which have associated advantages and disadvantages related to their physical properties and use. Furthermore, new surgical techniques with smaller vitreoretinal instruments have driven the use of more viscous substitutes. In this review, we analyze and discuss the most frequently used vitreous substitutes and look ahead to future alternatives. We classify these compounds based on their composition and structure, discuss their clinical use with respect to their associated advantages and disadvantages, and analyze how new vitreoretinal surgical techniques have modified their use.

The Changes of Retinal Saturation after Long-Term Tamponade with Silicone Oil

Purpose. To evaluate the effects of long-term tamponade with silicone oil on retinal saturation. Methods. A total of 49 eyes that received tamponade with silicone oil were included. The patients were divided into 3 groups (3–6 months, 6–9 months, and >9 months) according to the duration of silicone oil tamponade. Retinal oximetry was performed using the Oxymap system before and 2 months after silicone oil removal. Results. The mean retinal oxygen saturation before silicone oil removal was 107% ± 12% in the arterioles and 60% ± 10% in the venules, with an overall arteriovenous difference (AVD) of 47% ± 14%. The AVD in the >9-month group was significantly higher than that in the 3–6-month group (54% ± 16% versus 44% ± 11%, P = 0.042). After silicone oil removal, the AVD in the >9-month group was significantly decreased (45% ± 9% versus 54% ± 16%, P = 0.009); additionally, the arterioles were significantly wider than before surgery (10.8 ± 0.7 pixels versus 10.4 ± 0.9 pixels, P = 0.015). Conclusions. The tamponade with silicone oil for more than 9 months will cause the alterations of retinal saturation and the narrowing of retinal arterioles, which may further interfere with the oxygen metabolism in the retina.

Silicone implants and lymphoma: The role of inflammation

The risk of hematological malignancies is mainly determined by genetic background, age, sex, race and ethnicity, geographic location, exposure to certain chemicals and radiation; along with the more recently proposed immune factors such as chronic inflammation, immunodeficiencies, autoimmunity, and infections. Paradigmatic examples include the development of lymphoma in Sjögren's syndrome and Hashimoto thyroiditis, gastric MALT lymphoma in Helicobacter pylori infection, or lymphomas associated with infections by Epstein-Barr virus, human herpes virus 8 (HHV 8) and leukemia/lymphoma virus 1 (HTLV-1). A growing number of reports indicates an increased risk of lymphoma, particularly of the anaplastic large cell (ALCL) type. The implants, specifically those used in the past, elicit chronic stimulation of the immune system against the prosthetic material. This is particularly the case in genetically susceptible hosts. We suggest that polyclonal activation may result in monoclonality in those at risk hosts, ultimately leading to lymphoma. We suggest that patients with an inflammatory response against silicone implants be monitored carefully.

Vitreous substitutes: challenges and directions

The natural vitreous body has a fine structure and complex functions. The imitation of the natural vitreous body by vitreous substitutes is a challenging work for both researchers and ophthalmologists. Gases, silicone oil, heavy silicone oil and hydrogels, particularly the former two vitreous substitutes are clinically widely used with certain complications. Those, however, are not real artificial vitreous due to lack of structure and function like the natural vitreous body. This article reviews the situations, challenges, and future directions in the development of vitreous substitutes, particularly the experimental and clinical use of a new artificial foldable capsular vitreous body.