Use of Heavy Silicon Oil as Intraocular Tamponade for Inferior Retinal Detachment Complicated by Proliferative Vitreoretinopathy: A Multicentric Experience

INTRODUCTION

This is a multicentric study on the use of heavy silicon oil (HSO) as an intraocular tamponade for inferior retinal detachment (RD) complicated by proliferative vitreoretinopathy (PVR).

METHODS

139 eyes treated for RD with PVR were included in the study. 10 (7.2%) were affected by primary RD with inferior PVR, while 129 (92.8%) were affected by recurrent RD with inferior PVR. 102 eyes (73.9%) had received a silicon oil (SO) tamponade in a previous intervention prior to receiving HSO. Mean follow-up was 36.5 (standard deviation = 32.3) months.

RESULTS

The median interval between HSO injection and removal was 4 months (interquartile range: 3). At the time of HSO removal, the retina was attached in 120 eyes (87.6%), whereas in 17 eyes (12.4%), it had re-detached while the HSO was in situ. 32 eyes (23.2%) showed recurrent RD. A subsequent RD relapse was observed in 14.2% of cases with no RD at the time of HSO removal, and in 88.2% if an RD was present at the time of HSO removal. Advancing age showed a positive association with retinal attachment at the end of follow-up, while the risk of RD relapse at the end of the follow-up showed a significant negative association with HSO tamponade duration and with the use of SO rather than air or gas as post-HSO tamponade materials. Mean best corrected visual acuity was 1.1 logarithm of minimum angle of resolution at all follow-up time points. 56 cases (40.3%) needed treatment for elevated intraocular pressure (IOP), with which no clinically relevant variables were associated during follow-up.

CONCLUSION

HSO represents a safe and effective tamponade in cases of inferior RD with PVR. The presence of RD at the time of HSO removal is a negative prognostic factor for the development of a subsequent RD relapse. According to our findings, in cases of RD at the time of HSO removal, a short-term tamponade should definitely be avoided, in favor of SO. Special attention must be paid to the risk of IOP elevation, and patients should be closely monitored.

Advances in biomaterials as a retinal patch for the repair of rhegmatogenous retinal detachment

Rhegmatogenous retinal detachment (RRD) is the most common retinological emergency that can cause blindness without surgical treatment. RRD occurs when liquefied vitreous accumulates between the neurosensory retina and the retinal pigment epithelium via retinal breaks, which are caused by the separation of the vitreous from the retina with aging. Currently, the main treatment option is pars plana vitrectomy, which involves surgical removal of the vitreous and laser photocoagulation around retinal breaks to generate firm chorioretinal adhesion, as well as subsequent filling of the vitreous cavity with long-lasting substitutes (expansile gas or silocone oil) to prevent the connection between the subretinal space and the vitreous cavity via the breaks before the chorioretinal adhesion firm enough. However, the postoperative face-down position and the not very satisfactory first retinal reattachment rate place a heavy burden on patients. With the development of technology and materials engineering, researchers have developed biomaterials that can be used as a retinal patch to seal retinal breaks and prevent the connection of subretinal space and vitreous cavity via breaks, thus replacing the long-lasting vitreous substitutes and eliminating the postoperative face-down position. Preclinical studies have demonstrated that biomaterial sealants have enough biocompatibility and efficacy in the in vitro and in vivo experiments. Some sealants have been used in clinical trials on a small scale, and the results indicate promising application prospects of the biomaterial sealants as retinal patches in the repair of RRD. Herein, we review the recent advances in biomaterials as retinal patches for the repair of RRD, focusing on the biomaterial categories, methods, and procedures for sealing retinal breaks, as well as their biocompatibility and efficacy, current limitations, and development perspectives.

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.

Guideline for the treatment of no light perception eyes induced by mechanical ocular trauma

Severe mechanical ocular trauma with no light perception (NLP) predicts a poor prognosis of visual acuity and enucleation of the eyeball. Since the innovative treatment concept of exploratory vitreoretinal surgery has developed and treatment technology has advanced, the outcomes of severe ocular trauma treatment in NLP patients have greatly improved. However, there remains a lack of unified standards for the determination, surgical indication, and timing of vitrectomy in NLP eye treatment. To address these problems, we aimed to create evidence-based medical guidelines for the diagnosis, treatment, and prognosis of mechanical ocular trauma with NLP. Sixteen relevant recommendations for mechanical ocular trauma with NLP were obtained, and a consensus was reached. Each recommendation was explained in detail to guide the treatment of mechanical ocular trauma associated with NLP.

Biocompatibility and Efficacy of a Linearly Cross-Linked Sodium Hyaluronic Acid Hydrogel as a Retinal Patch in Rhegmatogenous Retinal Detachment Repairment

To prevent the migration of retinal pigment epithelium (RPE) cells into the vitreous cavity through retinal breaks after the pars plana vitrectomy for the repair of rhegmatogenous retinal detachment (RRD), sealing retinal breaks with an appropriate material appears to be a logical approach. According to a review of ocular experiments or clinical trials, the procedure for covering retinal breaks with adhesives is complex. A commercially available cross-linked sodium hyaluronic acid (HA) hydrogel (Healaflow®) with the injectable property was demonstrated to be a perfect retinal patch in RRD clinical trials by our team. Based on the properties of Healaflow®, a linearly cross-linked sodium HA hydrogel (HA-engineered hydrogel) (Qisheng Biological Preparation Co. Ltd. Shanghai, China) with the injectable property was designed, whose cross-linker and cross-linking method was improved. The purpose of this study is to report the characteristics of an HA-engineered hydrogel using Healaflow® as a reference, and the biocompatibility and efficacy of the HA-engineered hydrogel as a retinal patch in the rabbit RRD model. The HA-engineered hydrogel exhibited similar dynamic viscosity and cohesiveness and G′ compared with Healaflow®. The G′ of the HA-engineered hydrogel varied from 80 to 160 Pa at 2% strain under 25°C, and remained constantly higher than G″ over the range of frequency from 0.1 to 10 Hz. In the animal experiment, clinical examinations, electroretinograms, and histology suggested no adverse effects of the HA-engineered hydrogel on retinal function and morphology, confirming its favorable biocompatibility. Simultaneously, our results demonstrated the efficacy of the HA-engineered hydrogel as a retinal patch in the RRD model of rabbit eyes, which can aid in the complete reattachment of the retina without the need for expansile gas or silicone oil endotamponade. The HA-engineered hydrogel could play the role of an ophthalmologic sealant due to its high viscosity and cohesiveness. This pilot study of a small series of RRD models with a short-term follow-up provides preliminary evidence to support the favorable biocompatibility and efficacy of the HA-engineered hydrogel as a promising retinal patch for sealing retinal breaks in retinal detachment repair. More cases and longer follow-up studies are needed to assess its safety and long-term effects.

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.

INTRAOCULAR APPLICATION OF FIBRIN GLUE AS AN ADJUNCT TO PARS PLANA VITRECTOMY FOR RHEGMATOGENOUS RETINAL DETACHMENT

PURPOSE

To evaluate the efficacy of intraocular application of fibrin glue to seal the retinal breaks during standard pars plana vitrectomy for primary rhegmatogenous retinal detachment.

METHODS

Twenty-six eyes of 26 rhegmatogenous retinal detachment patients were included in the study. Fibrin glue was used to seal the retinal breaks during standard pars plana vitrectomy in all 26 eyes. Each eye was completely filled with a balanced saline solution at the end of the surgery. The success rate of the reattachment surgery, change in best-corrected visual acuity, intraocular pressure, and occurrence of intraoperative and postoperative complications were recorded and analyzed.

RESULTS

All eyes, with a mean age of 45.1 ± 18.3 years, were treated with pars plana vitrectomy surgery. During pars plana vitrectomy surgery, the fibrin glue showed excellent adherence and compliance to the retina. The glue was no longer visible through ultrasound scan 14.85 ± 4.56 days after surgery. The retinal breaks were sealed completely, and retina attached in all 26 eyes with no occurrence of rhegmatogenous retinal detachment during the follow-up period. The best-corrected visual acuity at 6 months after operation was significantly improved from preoperation best-corrected visual acuity. After operation, two eyes (2/26) developed an epiretinal membrane. Although three eyes (3/26) had a transient increased intraocular pressure during the 1st week after surgery, the intraocular pressure lowered to the normal range after the application of timolol. One eye (1/26) required daily topical antiglaucoma drops to lower the intraocular pressure. No adverse effects of fibrin glue were observed.

CONCLUSION

The fibrin glue provided a superior adhesive effect for sealing retinal breaks, while showing no additional adverse effects. It is a worthy alternative to gas tamponade for rhegmatogenous retinal detachment vitrectomy surgery.

Supine positioning after vitrectomy for rhegmatogenous retinal detachments with inferior retinal breaks

Background

To evaluate the effectiveness of face up position (FUP) following pars plana vitrectomy (PPV) and silicone oil injection in cases of rhegmatogenous retinal detachment (RRD) with multiple peripheral and inferior breaks.

Method

Thirty-two eyes of 32 patients with RRD due to multiple peripheral breaks were managed with PPV and silicone oil as endotamponade. Postoperatively, all patients were instructed to assume face up (supine) position for at least 10 days. Silicone oil was removed 3 to 6 months postoperatively in eyes with attached retina and the patients were followed up for 6 months.

Results

Thirty eyes (94%) got a successful attachment of the retina and remained attached after silicone oil removal. One case showed lower redetachment under silicone oil while the other case showed recurrent RRD after silicone oil removal.

Conclusion

Although postoperative FUP is not a popular one, it is effective in the treatment of RRD with peripheral breaks whatever the number or the distribution of these breaks. This may in some way or another change the traditional trends of postoperative positioning after vitrectomy for RRD.

Study of wetting of the animal retinas by Water and organic liquids and its Implications for ophthalmology

Interfacial properties of the animal retinas are reported. Wetting of the retina-retinal pigment epithelium-choroid-sclera tissues of cow, sheep, and pig eyes by water, silicone and castor oil was explored experimentally. Both water and silicone oils demonstrated complete wetting of the retina, regardless of the viscosity of the silicone oil, whereas the castor oil demonstrated a partial wetting regime. Similar wetting regimes were observed for sheep, cow and pig retinas. The intact surface of animal retina was found to be both hydrophilic and oleophilic. Wetting experiments with double sandwich oil/water layers were performed. Water demonstrated stronger affinity to the retina than silicone and castor oils, and eventually replaced the oils at the liquid/retina interface. We conclude that aqueous solutions continuously secreted in the living eye may displace silicone oil from the retinal surface and contribute to retinal re-detachment. Study of dynamics of wetting of the animal retina by water and organic oils is reported. The exponent describing the dynamics of spreading of the castor oil is lower than that predicted by the Tanner law. Castor oil may provide more effective tamponade than silicone oil.

Analysis of the rates of emulsification in intraocular silicone oil tamponades of differing viscosities

AIM

To investigate the rates of emulsification in silicone oil (SO) tamponades of differing viscosities used during pars plana vitrectomy (PPV) in the treatment of complicated vitreoretinal diseases.

METHODS

This study was a prospective randomized clinical trial. Totally 290 cases with greater likelihoods of secondary detachment were included and randomly grouped into either Siluron 2000 (n=143) or Siluron 5000 (n=147) SO tamponades with 23-gauge PPV. Patient follow-ups and data analyses were conducted 1, 3, 6, and 12mo post-surgery.

RESULTS

The time of the SO emulsification ranged from 1 to 17mo, with a mean of 7.3±4.2mo. The Siluron 5000 group showed a slower emulsification rate in comparison to the Siluron 2000 group. The Siluron 2000 group took a shorter time to show signs of emulsification, necessitating earlier SO removal. However, there were no significant differences in the occurrence of complications, including secondary retinal detachment, cataract, corneal abnormality, high intraocular pressure and hypotony.

CONCLUSION

The Siluron 2000 SO tamponade shows a faster rate of emulsification than the Siluron 5000 SO, necessitating earlier removal. Both groups show similar results in terms of anatomical success and visual acuity outcome, and there is no significant difference between the SOs regarding the occurrence of complications.

Burkholderia cepacia, a cause of post pars plana vitrectomy silicone oil related endophthalmitis: clinico-pathological presentation and outcome of management

Aim

To report the long-term outcome of the management of a series of culture proven post pars plana vitrectomy endophthalmitis in which the infective agent was in the silicone oil used as an endotamponade. The isolates were Burkholderia cepacia and Pseudomonas aeruginosa.

Method

A retrospective interventional reporting of a series consisting of a cluster of five cases.

Cases

Five consecutive patients received the same batch of 5000-centistoke silicone oil as endotamponade at the conclusion of vitreoretinal surgery and presented with features of acute intraocular inflammation, which was due to an infective cause. The infective organism isolated from the mixture of silicone oil and fluid was B. cepacia in three out of the initial cluster of four eyes and P. aeruginosa in the fifth eye.

Outcome of management

The initial 4 eyes evolved into eyes with poor vision (hand motion, perception of light and no perception of light), advanced proliferative vitreoretinopathy, hypotony, phthisis bulbi and cornea opacity. The poor visual outcome was deemed to be consequent to delay in removal of the silicone oil, despite use of intravitreal, systemic and topical antibiotics. The fifth case, because of the heightened index of suspicion gained from the preceding four cases, had a prompt removal of the silicone oil, vitreal lavage with antibiotics, and intravitreal injection of antibiotics and steroid. He regained a 6/9 vision.

Conclusion

Gram-negative bacilli can colonize silicone oil resulting in post pars plana vitrectomy endophthalmitis. The index of suspicion for this should be high and can be managed successfully with prompt removal of the silicone oil, microbial sensitive antibiotic lavage of the vitreous cavity, followed by a repeat tamponade.

A Review of Surgical Outcomes and Advances for Macular Holes

The surgical outcomes of macular holes (MHs) have improved greatly in recent years. The closure rate is as high as 90-100%, but the outcomes of some special types of MHs remain unsatisfactory. Internal limiting membrane (ILM) peeling dramatically improves the anatomic success rate, but recent studies have found that it could also cause mechanical and subclinical traumatic changes to the retina. Dyes are widely used, and apart from indocyanine green (ICG), the toxicities of other dyes require further research. Face-down posturing is necessary for MHs larger than 400 μm, and the duration of this posture is determined by the type of tamponade and the case. The ellipsoid zone has been shown to be highly correlated with visual outcome and recovery. New surgical methods include the inverted ILM flap technique and the ILM abrasion technique. However, they require further research to determine their effectiveness.

Feasibility of using experimental high viscosity silicone oils: a pilot study

Background

Polydimethyl silicones (silicone oils) are used in complex retinal surgeries, including difficult or recurrent retinal detachments, severe eye trauma, and other indications for long term tamponade. Two major problems with currently available silicone oils are emulsification and recurrent retinal detachment. The primary endpoint of this study was to evaluate the toxicity and safety of high viscosity silicone oils and second, the feasibility of using them with currently available vitrectomy systems.

Methods

In this experimental study, 8 eyes of 8 New Zealand White rabbits underwent vitrectomy. The vitreous cavities of 2 eyes were filled with medical grade 5500 cS silicone oil, 4 eyes with 12,500 cS oil, and 2 eyes with 30,000 cS oil for 3 months, after which the animals were sacrificed and the eyes sent for histopathological examination. The duration required to inject 5 cc each of 1300, 12,500 and 30,000 cS oils, using a commercially available system (Alcon VFC Pac) were also evaluated.

Results

Retinal histopathology was comparable in all eyes, with no excess toxic effect or damage seen in eyes with experimental oils. All oils were readily injectable with the VFC Pac system.

Conclusions

High viscosity experimental silicone oils have similar chemical and physical properties to lower viscosity oils currently used. Therefore, toxicities are expected to be similar. In a small pilot sample of 8 rabbit eyes filled with silicone oil for 3 months, histopathology in eyes with 12,500, 30,000 cS or medical grade 5500 cS silicone oil were similar. Injecting these oils using available vitrectomy equipment is feasible. New, high viscosity silicone oils may offer several advantages over currently available oils for some patients.

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.

Comparison of the antimicrobial effect of heavy silicone oil and conventional silicone oil against endophthalmitis-causing agents

Purpose:

To conduct an in vitro experimental study comparing the effectiveness of conventional silicone oil and heavy silicone oil against endophthalmitis-causing agents.

Materials and Methods:

The antimicrobial activity of conventional silicone oil (RS OIL 5000) and heavy silicone oil (heavySil 1500) was tested. The antimicrobial effects of both silicone oils were determined by the growing capability of the microorganism.

Results:

The number of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans decreased to zero levels at the second day of inoculation in heavy silicone oil. In conventional silicone oil, the microorganisms survived longer than in heavy silicone oil.

Conclusion:

Heavy silicone oil seems to be more effective than conventional silicone oil against endophthalmitis-causing agents.

Anatomical and functional outcomes after Densiron 68 heavy silicone oil tamponade for complicated retinal detachment in Chinese eyes

AIM

To evaluate the safety and efficacy of Densiron 68 heavy silicone oil (HSO) tamponade for complicated retinal detachment (RD) in Chinese eyes.

METHODS

Twenty-one eyes of 21 patients with complicated RD were included in this retrospective study. All patients underwent pars plana vitrectomy with an internal tamponade using Densiron 68 HSO. Anatomical and functional results and complications were evaluated, including retinal status, visual acuity (VA), intraocular pressure (IOP), intraocular inflammation, lens opacity, and HSO emulsification.

RESULTS

All the patients were followed up for 3mo to 1y (5.8±1.16mo). Retinal reattachment was achieved in 19 of 21 patients (90.5%). VA improved in 18 of 21 patients (85.7%), from 1.93 logMAR (±0.48) to 1.52 logMAR (±0.45) (P=0.001). Postoperative complications included early dispersion of HSO in 7 eyes (38.8%), cataract in 10 of 18 phakic eyes (55.5%), moderate postoperative inflammation reaction in 10 eyes (47.6%), and elevated IOP in 5 eyes (23.8%), all of which were controlled by medication or by surgery.

CONCLUSION

High anatomical and functional success rates can be achieved with primary vitrectomy for complicated RD by using Densiron 68 HSO; however, it should not be ignored that Densiron 68 HSO can cause some complications in the eye.

Perfluorocarbon liquid: its application in vitreoretinal surgery and related ocular inflammation

The application of perfluorocarbon liquids has been well acclaimed in vitreoretinal surgery. Its unique physical properties make it an ideal intraoperative tool to improve the efficiency and safety of surgical procedures in complicated cases. The main functions of perfluorocarbon liquids in vitreoretinal surgery include relocating and fixing the detached retina, displacing the subretinal and subchoroidal to fluid anteriorly, revealing proliferative vitreous retinopathy (PVR) for further maneuvers, protecting the macula from exposure to chemicals with potential toxicity, and assisting the removal of foreign body. The related clinical applications include retinal detachment with severe proliferative vitreoretinopathy, giant tear, diabetic retinopathy (DR), retinopathy of prematurity (ROP), and posterior dislocated crystalline and intraocular lenses. The application of perfluorocarbon liquids has been expended over the past fewer years. Several PFCLs related ocular inflammations have been observed in in vitro studies, animal studies, and clinical follow-up. The complete removal of PFCLs is recommended at the end of the surgery in most cases.

Endotamponades in pars plana vitrectomy for metallic intraocular foreign body associated with endophthalmitis

AIM

To study the criterion-reference of endotamponades in pars plana vitrectomy for metallic intraocular foreign body (MIOFD) associated with endophthalmitis.

METHODS

Thirty-six patients of MIOFD with endophthalmitis accorded with exclusion and inclusion criteria were retrospectively analyzed. A detailed analysis of the patients' natural factors, preoperative examinations, intraoperative endotamponades choice, postoperative complications and therapeutic effects was performed.

RESULTS

BSS was used in 4 eyes without obvious retinal damage. There was no postoperative complication and the visual acuity (VA) was improved. Sixteen eyes that had mild retinal damage filled with C3F8 gas. The postoperative VA improved in 10 eyes (62.5%), 4 eyes (25.0%) remained unchanged and 2 eyes (12.5%) decreased. Only 2 cases occurred postoperative retinal detachment in gas group. Another 16 eyes with serious retinal damage were treated with silicone oil. Postoperative VA of 9 eyes (56.3%) improved, 3 eyes (18.8%) remained unchanged and 4 eyes (25.0%) decreased. The silicone oil group had higher incidence of postoperative complications, but the incidence of secondary treatment had no significant different between silicone oil and gas group.

CONCLUSION

An appropriate choice of endotamponades in vitrectomy surgery for MIOFB with endophthalmitis is important for prognosis.