Perfluorocarbon liquids in vitreoretinal surgery: a review of applications and toxicity

Reasons why life on Earth rarely makes fluorine-containing compounds and their implications for the search for life beyond Earth

Life on Earth is known to rarely make fluorinated carbon compounds, as compared to other halocarbons. We quantify this rarity, based on our exhaustive natural products database curated from available literature. We build on explanations for the scarcity of fluorine chemistry in life on Earth, namely that the exclusion of the C-F bond stems from the unique physico-chemical properties of fluorine, predominantly its extreme electronegativity and strong hydration shell. We further show that the C-F bond is very hard to synthesize and when it is made by life its potential biological functions can be readily provided by alternative functional groups that are much less costly to incorporate into existing biochemistry. As a result, the overall evolutionary cost-to-benefit balance of incorporation of the C-F bond into the chemical repertoire of life is not favorable. We argue that the limitations of organofluorine chemistry are likely universal in that they do not exclusively apply to specifics of Earth's biochemistry. C-F bonds, therefore, will be rare in life beyond Earth no matter its chemical makeup.

Transition metal complexes of the (2,2,2-trifluoroethyl)phosphinate NOTA analogue as potential contrast agents for 19F magnetic resonance imaging

A new hexadentate 1,4,7-triazacyclononane-based ligand bearing three coordinating methylene-(2,2,2-trifluoroethyl)phosphinate pendant arms was synthesized and its coordination behaviour towards selected divalent (Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+) and trivalent (Cr3+, Fe3+, Co3+) transition metal ions was studied. The ligand forms stable complexes with late divalent transition metal ions (from Co2+ to Zn2+) and the complexes of these metal ions are formed above pH ∼3. A number of complexes with divalent metal ions were structurally characterized by means of single-crystal X-ray diffraction. The complex of the larger Mn2+ ion adopts a twisted trigonally antiprismatic geometry with a larger coordination cavity and smaller torsion of the pendant arms, whereas the smaller ions Ni2+, Cu2+ and Zn2+ form octahedral species with a smaller cavity and larger pendant arm torsion. In the case of the Co2+ complexes, both coordination arrangements were observed. The complexes with paramagnetic metal ions were studied from the point of view of potential utilization in 19F magnetic resonance imaging. A significant shortening of the 19F NMR longitudinal relaxation times was observed: a sub-millisecond range for complexes of Cr3+, Mn2+ and Fe3+ with symmetric electronic states (t2g3 and HS-d5), the millisecond range for the Ni2+ and Cu2+ complexes and tens of milliseconds for the Co2+ complex. Such short relaxation times are consistent with a short distance between the paramagnetic metal ion and the fluorine atoms (∼5.5-6.5 Å). Among the redox-active complexes (Mn3+/Mn2+, Fe3+/Fe2+, Co3+/Co2+, Cu2+/Cu+), the cobalt complexes show sufficient stability and a paramagnetic-diamagnetic changeover with the redox potential lying in a physiologically relevant range. Thus, the Co3+/Co2+ complex pair can be potentially used as a smart redox-responsive contrast agent for 19F MRI.

Use of Perfluorochemicals in Li-Air Batteries: A Critical Review

As lithium-ion (Li-ion) batteries approach their theoretical limits, alternative energy storage systems that can power technology with greater energy demands must be realized. Li-metal batteries, particularly Li-air batteries (LABs), are considered a promising energy storage candidate due to their inherent lightweight and energy-dense properties. Unfortunately, LAB practicality remains hindered by inadequate oxygen solubility and diffusion rates within the electrolyte, both which are fundamental for LAB operation. Due to exceptionally high oxygen solubilities, perfluorochemicals (PFCs) have been investigated as a promising solution to this issue. Although PFCs have been reported to enhance LAB performance and longevity when implemented within the cathodic regions of LABs in several studies, the influence of this class of compounds on other components of the battery (including the anode and the electrolyte) is also highly important. This paper reviews the use of PFCs in LABs to date and discusses the performance enhancements resulting from their implementation. We identify and discuss future prospects and emerging research directions for the use of PFCs into LAB design, in the effort toward realization of high-performing LAB technologies.

Management, risk factors and treatment outcomes of rhegmatogenous retinal detachment associated with giant retinal tears: scoping review

BACKGROUND

Rhegmatogenous retinal detachment (RRD) is a serious condition that occurs when the retina detaches from its underlying retinal pigment epithelium. RRDs associated with giant retinal tears (GRTs) are caused by retinal tears at least 90° or one-quarter of the circumferential extent. This scoping review systematically identifies and summarizes clinical studies evaluating surgical techniques for the management of GRT-related RRDs, discusses functional and visual outcomes and the risk factors affecting treatment outcomes.

METHODS

This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Scopus, Google Scholar, and Springer Link databases were searched for relevant papers (from January 2001 to March 2023). Studies that were published in the English language and reported the risk factors, management, and treatment outcomes of GRT-related RRDs were included in the review. The outcome measures included anatomic success rates, changes in BCVA (logMAR) from baseline to the final follow-up, and adverse events.

RESULTS

A total of 11,982 articles were identified. After the title and abstract review, 71 studies were deemed eligible for full-text review. Thirty-six studies that met the eligibility criteria were included in the final review. Four surgical techniques were identified: pars plana vitrectomy (PPV), combined PPV and scleral buckling, scleral buckling alone, and pneumatic retinopexy. Various types of tamponades, including gas, silicone oil, and air, have been used. PPV was the most commonly used surgical technique in 33.1-100% of patients. Among the 20 studies that used PPV alone, 17 were associated with preoperative PVR. In addition, scleral buckling alone or in combination with PPV was reported as a treatment option in 10 studies, with 2-100% of patients experiencing scleral buckling alone and 13.6-100% experiencing combined PPV and complementary scleral buckling. Primary anatomic success (PAS) was achieved with retinal reattachment via a single operation with no residual tamponade, whereas final anatomic success (FAS) was achieved via more than one operation with no residual tamponade. Reported single surgery anatomic success (SSAS) rates range from 65.51 to 100%. The preoperative best-corrected visual acuity (BCVA) ranged from 0.067 to 2.47 logMAR, whereas the postoperative BCVA ranged from 0.08 to 2.3 logMAR. An improvement in visual acuity was observed in 29 studies. Cataracts (3.9-28.3%) were the most common postoperative complication, followed by high IOP (0.01-51.2%) and PVR (0.8-31.57%).

CONCLUSION

PPV is the most common surgical technique, and currently microincision vitrectomy surgery (MIVS) systems are commonly employed. Silicone oil is the most frequently used tamponade in RRD repair. Risk factors for GRT-related RRD include age, sex, lens status, high myopia status, proliferative vitreoretinopathy (PVR), presenting visual acuity, the extent of the GRT and retinal detachment, and macular involvement. Future research areas include guidelines to reduce variability in the reporting of surgical methodology, choice of tamponades, and reporting of functional and visual outcomes to inform the best therapeutic interventions in GRT-related RRD.

Efficacy of the use of perfluorocarbon as a temporary tamponade agent in severe ocular trauma and/or complex retinopexy: a scoping review

BACKGROUND

Perfluorocarbon (PFC)possesses unique chemical properties that favor the pigment epithelium's adhesion and allows the drainage of subretinal fluid through retinal holes present in retinal detachment cases. However, PFC as a temporary tamponade agent has been limited due to its high potential for toxicity.

MAIN BODY

We conducted a scoping review regarding the use of PFC in vitreoretinal surgery as a temporary tamponade in subjects with severe ocular trauma or severe retinal detachment who received a therapeutic intervention (vitrectomy via posterior approach with the use of PFC as a temporary tamponade), compared to vitrectomy without the use of PFC as a temporary tamponade. Outcomes of interest were retinal reattachment, visual acuity (VA), postoperative complications and retinal toxicity. The search was performed in Medline, Medline In-Process & Other Non-Indexed Citations, Medline Daily Update, Embase databases. Reference lists from relevant review articles were also included. Two hundred thirty-eight studies were found, with no duplicate entries. In the first selection, 230 articles were eliminated; in the second selection, 6 additional articles were discarded. In total, 8 articles were obtained in this review. Two selected articles corresponded to animal studies and 6 to studies in humans. Regarding study design, 5 were case series, and 1 was a cohort study.

CONCLUSION

PFC as a short-term tamponade had high rates of reapplication, improved VA, and the most frequent adverse effects were reversible after PFC withdrawal. Nonetheless, the quality of the studies was poor. Studies with more rigorous methodologies are needed to determine visual and structural outcomes and potential risks of PFC use as a temporary tamponade in vitreoretinal surgery.

MEDIUM-TERM PERFLUORO-N-OCTANE AS RESCUE POSTOPERATIVE TAMPONADE FOR VERY COMPLEX RETINAL DETACHMENTS: ANATOMICAL AND FUNCTIONAL OUTCOMES

PURPOSE

To report the anatomical and functional outcomes of medium-term perfluoro-n-octane (PFO) tamponade as a rescue procedure in very complex retinal detachments (RDs).

METHODS

We reviewed the case records of 35 consecutive patients who underwent vitrectomy for very complex RDs due to diverse etiologies. The surgical complexity was so graded because of the intraoperative failure to ascertain complete retinal reattachment; perfluoro-n-octane was used as rescue tamponade for 2 to 4 weeks. The second intervention included additional membrane peeling, retinectomy, endophotocoagulation, and gas/silicone oil tamponade. The minimum follow-up was 3 months after the final intervention: the primary outcome was retinal reattachment and the secondary outcome was change in best-corrected visual acuity (BCVA).

RESULTS

The most common presentations were severe trauma with retinal incarceration, preretinal and subretinal hemorrhage, or chronic/recurrent RDs with anterior proliferative vitreoretinopathy. Preoperative BCVA was ≤counting fingers in 31 (88.6%) patients. Complete retinal attachment without any tamponade was achieved in 33 (94.3%) eyes. best-corrected visual acuity improved in 30 (85.7%) eyes: 16 (45.7%) had BCVA ≥20/200 and 21 (60%) regained ambulatory vision (≥5/200). Two eyes developed keratopathy, and four needed antiglaucoma medications.

CONCLUSION

We achieved excellent anatomical outcomes and acceptable functional outcomes in nearly inoperable RDs with few side effects. Medium-term perfluoro-n-octane tamponade can be used as a salvage procedure in very complex RDs where intraoperative reattachment cannot be ensured.

Meropenem loaded 4-arm-polyethylene-succinimidyl-carboxymethyl ester and hyaluronic acid based bacterial resistant hydrogel

Developing an ideal vitreous substitute/implant is a current challenge. Moreover, implants (e.g., heart valves and vitreous substitutes), are associated with a high risk of bacterial infection when it comes in contact with cells at implant site. Due to infection, many implants fail, and the patient requires immediate surgery and suffers from post-operative problems. To overcome these problems in vitreous implants, we developed a bacterial resistant vitreous implant, where meropenem (Mer), an antibiotic, has been incorporated in a hydrogel prepared by crosslinking HA (deacetylated sodium hyaluronate) with 4-arm-polyethylene-succinimidyl-carboxymethyl-ester (PESCE). The HA-PESCE hydrogel may serve as a suitable artificial vitreous substitute (AVS). The pre-gel solutions of HA-PESCE without drug and with the drug are injectable through a 22 G needle, and the gel formation occurred in approx. 3 min: it indicates its suitability for in-situ gelation through vitrectomy surgery. The HA-PESCE hydrogel depicted desired biocompatibility, transparency (>90 %), water content (96 %) and sufficient viscoelasticity (G' >100 Pa) calculated after 1 month in-vitro, which are suitable for vitreous substitute. The HA-Mer-PESCE hydrogel showed improved biocompatibility, suitable transparency (>90 %), high water content (96 %), and suitable viscoelasticity (G' >100 Pa) calculated after 1 month in-vitro, which are suitable for vitreous substitute. Further, hydrogel strongly inhibits the growth of bacteria E.coli and S.aureus. The drug loaded hydrogel showed sustained in-vitro drug release by the Fickian diffusion-mediated process (by Korsmeyer-Peppas and Peppas Sahlin model). Thus, the developed hydrogel may be used as a potential bacterial resistant AVS.

Perfluorocarbon liquid-assisted vitreo-dissection in eyes with firmly adherent posterior hyaloid

BACKGROUND

Induction of posterior vitreous detachment (PVD) is a critical step during pars plana vitrectomy. Multiple techniques and utilities have been proposed for assistance with this step with no consensus on the safest and most effective means, especially in eyes with firmly adherent posterior hyaloid. Viscodissection or the utilization of perfluorocarbon liquid (PFCL) can be used to dissect the posterior hyaloid and widely adherent epiretinal membranes.

METHODS

A technique of PFCL dissection of the posterior hyaloid in eyes with abnormal adhesion of the posterior hyaloid. After core vitrectomy, breaking into the posterior hyaloid face is made via active aspiration and cutting or a sharp dissection. This is followed by active and slow injection of PFCL into the potential space between the posterior cortical vitreous and the neurosensory retina. A wave of PFCL propagates anteriorly causing "vitreo-dissection" of the peripheral cortical vitreous.

RESULTS

The technique was effective and safe in 8 successive cases, 4 cases with vitreoretinal traction syndrome and 4 with diabetic tractional membranes.

CONCLUSION

The technique can be considered in cases with abnormal firmly adherent posterior hyaloid when induction of PVD proves difficult.

Vitrectomy for Complicated Retinal Detachment Without the Use of Perfluorocarbon Liquid: A Real-World Data and Retrospective Study

Introduction

This study aimed to evaluate the effectiveness of vitrectomy without using perfluorocarbon liquid (PFCL) for the treatment of complicated retinal detachment (RD).

Methods

The utilisation of PFCL was calculated in four hospitals in 2020 and in one hospital every year from 2012 to 2020. A case series of 320 RD eyes treated with vitrectomy without the use of perfluorocarbon liquid (VWTPL) was followed up for 1–26 months. The rate of retinal reattachment (RR) and postoperative visual acuity (VA, LogMAR) was evaluated. Furthermore, factors influencing RR and VA were analysed.

Results

The overall utilisation of PFCL was 43.87% (42.74%, 45.83%, 62.39% and 4.5%). The annual utilisation was 46.94%, 20.43%, 46.73%, 47.41%, 20%, 17.24%, 7.60%, 10.67% and 4.49% from 2012 to 2020. The VA of 320 eyes improved from 1.96 ± 1.07 preoperatively to 1.43 ± 0.92 (LogMAR, p < 0.001) 1 week post-operation. In the follow-up of 1–26 months (median: 9 months), the primary and final RR was 87.37% and 95.56%, respectively. Age, uveitis, recurrent RD, the number of detached retinal quadrants, aPVR and preoperative VA were considered as the factors influencing postoperative VA. Moreover, preoperative VA and preoperative intraocular pressure were the factors influencing RR.

Conclusion

The utilisation of PFCL varies amongst hospitals with a highest percentage of 62.39%. VWTPL is safe and effective, thereby saving costs and preventing complications related to PFCL.

Trial Registration

ChiCTR-ORC-17014225.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40123-022-00479-x.

Acute intraocular toxicity caused by perfluorocarbon liquids: safety control systems of medical devices

BACKGROUND

Acute retinal toxicity has been demonstrated to be associated with the intraoperative use of perfluorocarbon liquids (PFCLs), especially perfluorooctane (PFO). Recently, several cases of PFO-associated blindness have been reported in Spain, Holland, France, Italy, the Middle East, and South America.

METHODS

As a result, a new ISO guideline (ISO 16672:2020) was drafted, discussed, approved, and released in 2019. This recent ISO16672:2020 guideline recommends performing direct cytotoxicity tests as an option along with chemical analysis to measure PFCL quality (purity and safety).

RESULTS

In this review paper, it has been emphasized why an appropriate biological test, specifically direct exposure of PFCL to live cells, for measuring cytotoxicity must be performed with each PFCL batch along with chemical analysis.

CONCLUSIONS

The paper intends to compile all available information to discuss possible approaches for avoiding adverse clinical cases in future.

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.

Vitreous inflammation and macular edema secondary to perfluoro-n-octane toxicity

Although it is not frequent, residual perfluoro-n-octane elicits an inflammatory response in form of macroscopic white flake-like material on intraocular structures formed by macrophages with intracellular vacuoles containing it. Macular edema could be another manifestation of this entity which, to our knowledge, has not been described so far. We describe an unusual case of intravitreal inflammation and macular edema secondary to the presence of residual perfluoro-n-octane after a surgical intervention of retinal detachment.

Refining the Removal of Perfluorocarbon Liquid Remnants Through Negative Staining With Vital Dyes

The complete removal of perfluorocarbon liquid (PFCL) after complex vitreoretinal surgery can be a challenging task. However, it remains a crucial step to avoid several ocular complications associated with retained PFCL. In this report, the authors describe a simple and effective technique to highlight the presence of retained PFCL bubbles in the epiretinal space through negative staining with vital dyes. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:153-154.].

Vitreous substitutes: An overview of the properties, importance, and development

Vitreous or vitreous humor is a complex transparent gel that fills the space between the lens and retina of an eye and acts as a transparent medium that allows light to pass through it to reach the photoreceptor layer (retina) of the eye. The vitreous humor is removed in ocular surgery (vitrectomy) for pathologies like retinal detachment, macular hole, diabetes-related vitreous hemorrhage detachment, and ocular trauma. Since the vitreous is not actively regenerated or replenished, there is a need for a vitreous substitute to fill the vitreous cavity to provide a temporary or permanent tamponade to the retina following some vitreoretinal surgeries. An ideal vitreous substitute could probably be left inside the eye forever. The vitreous humor is transparent, biocompatible, viscoelastic and highly hydrophilic; polymeric hydrogels with these properties can be a potential candidate to be used as vitreous substitutes. To meet the tremendous demand for the vitreous substitute, many scientists all over the world have developed various kinds of vitreous substitutes or tamponade agent. Vitreous substitutes, whatsoever developed till date, are associated with several advantages and disadvantages, and there is no ideal vitreous substitute available till date. This review highlights the polymer-based vitreous substitutes developed so far, along with their advantages and limitations. The gas-based and oil-based substitutes have also been discussed but very briefly.

Influence of Perfluorocarbon Liquids on Peripapillary Retinal Nerve Fiber-Layer Thickness Following Pars Plana Vitrectomy with Silicone Oil-Based Endotamponade

Background

Inner retina–layer modifications after pars plana vitrectomy (PPV) can be objectively assessed through spectral domain optical coherence tomography (SD-OCT).

Methods

This study explored prospectively changes in retinal nerve-fiber layer (RNFL) thickness with SD-OCT in eyes undergoing PPV with silicone oil–based tamponade with and without use of perfluorocarbon liquids (PFCLs) during the early postoperative phase (up to 3 months) at the Research Institute of Ophthalmology, Egypt.

Results

Thirty patients were recruited who underwent PPV and silicone oil–based tamponade for either retinal detachment or diabetic retinopathy between April 2019 and September 2019. Mean RNFL thickness showed no significant change during follow-up at the first week (102.90±30.68 mm), 1 month (107.30±32.27), or three months (105.90±36.68; p=0.46, 0.68). There were significant correlations noticed between RNFL thinning and axial length of eyes, intraocular pressure, and use of PFCLs during the follow-up period.

Conclusion

The RNFL tends to change postvitrectomy, but not significantly. Careful examination and consistent follow-up is required for postvitrectomy patients with larger axial length and intraoperative PFCL use.

Double Retinal Tamponade for Treatment of Rhegmatogenous Retinal Detachment with Proliferative Vitreoretinopathy and Inferior Breaks

Purpose

To evaluate the efficacy and safety of the simultaneous use of short-term perfluoro-n-octane (PFO) with perfluoropropane (C3F8) gas to achieve retinal reattachment in eyes with rhegmatogenous retinal detachment (RRD) with proliferative vitreoretinopathy (PVR) grade C and multiple retinal breaks including inferior breaks.

Design

This is a prospective interventional case series study. Patients and Methods. The study was a prospective noncomparative interventional study. It included 30 eyes of 30 patients who had RRD with PVR grade C and multiple retinal breaks including inferior tears attending the vitreoretinal unit of Minia University Hospital, Egypt. The mean age was 50.2 ± 10.63 years; 18 patients were females and 12 were males. Combined phacoemulsification and 23 G pars plana vitrectomy (PPV) with double retinal tamponade by C3F8 and PFO were done, and PFO was removed in 10–14 days. The patients were followed up for one year. The primary outcome was to achieve successful retinal reattachment, and the secondary outcomes were visual improvement and occurrence of complications.

Results

Successful retinal reattachment was obtained in 28 eyes out of 30 (93.3%), and 2 eyes (6.7%) had recurrent RD. Best-corrected distance visual acuity (BCDVA) in logMAR was significantly improved from baseline 1.74 ± 0.05 to 0.93 ± 0.04, 0.82 ± 0.05, 0.80 ± 0.07, and 0.73 ± 0.055 at follow-up visits 3, 6, and 9 months and one year, respectively (P ≤ 0.001). There were no serious ocular complications recorded.

Conclusions

The results of this study indicated that primary vitrectomy with simultaneous use of both C3F8 and short-term PFO as retinal tamponades was effective and safe in the management of complex cases of RRD with PVR grade C and inferior breaks. This trial is registered with NCT04168255.

Medium-term tamponade with vitrectomy and perfluorodecalin for the management of complex retinal detachments

PURPOSE

To describe the clinical presentation, anatomical and visual outcome of a series of patients in our department with complex retinal detachments, managed with vitrectomy and perfluorodecalin (PFD) for medium-term tamponade.

STUDY DESIGN

Retrospective case series.

METHODS

Retrospective analysis of the medical records of all patients in the last 6 years presenting with complex retinal detachment managed with vitrectomy where PFD was used as a medium-term tamponade.

RESULTS

A total of 85 eyes in 85 patients were included in the study, with a mean follow-up period of 16.0 ± 2.67 months (range 3-59). About 26 detachments presented with associated PVR-C, and 10 had giant retinal tears. The location of the retinal detachment was inferior in 40% of cases, and total in 18.9% of cases. Anatomical success, defined as retinal reattachment at 12 months, was achieved in 98.8% of cases, and there was a mean improvement in BCVA of logMAR 0.64 ± 0.20, which was statistically significant (p < 0.001, paired t-test 6.23). Of the 41 phakic eyes included in the study, 20 underwent cataract surgery within the follow-up period.

CONCLUSION

In this case series, we have demonstrated a 98.8% anatomical success and significant improvement in BCVA, with no reports of retinal toxicity. Medium-term tamponade PFD appears to be an efficacious and safe technique for management of a variety of complex retinal detachments, including those secondary to GRT, the presence of PVR-C, inferior location, tractional, traumatic, and re-detachments.

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.

Effects of perfluorocarbon liquids in macular hole retinal detachment treatment

OBJECTIVE

This study aims to evaluate the clinical efficacy and visual function prognosis of macular hole retinal detachment treatment for high myopia by inverting the internal limiting membrane to overlay the macular hole with the assistance of perfluorocarbon liquids.

METHODS

A total of 55 high myopia patients, who received macular hole retinal detachment treatment from 2013 to 2016, were included in this study. Among these patients, 38 patients were assigned to the first group and 17 patients (perfluorocarbon liquids) were assigned to the second group. The second group was further divided into two subgroups, according to the overlaying layer number of the internal limiting membrane valve: A group (multiple layers) and B group (single layer).

RESULTS

The success rate of the internal limiting membrane inversion and overlaying on the macular hole was 23.68% and 100% in the first and second group, respectively. The differences in macular hole closing rate and postoperative best-corrected visual acuity between these two groups were statistically significant (p < 0.05). Furthermore, the differences in macular morphology recovery between the A and B groups were also statistically significant (p = 0.004 < 0.05).

CONCLUSION

Perfluorocarbon liquids play a positive role in the operation process of the internal limiting membrane.

Surgical Removal of Submacular Perfluorocarbon Liquid Using a 41-Gauge Extendible Subretinal Injection Needle

Submacular perfluorocarbon liquid (PFCL) retention is a well-known complication of vitreoretinal surgeries; however, the optimal surgical technique for the removal of subfoveal PFCL is yet to be determined. We describe a novel surgical technique for the removal of retained submacular PFCL by performing a retinotomy adjacent to the inferotemporal arcade using a 41-gauge extendible subretinal injection needle and inducing a therapeutic retinal detachment. Through the same retinotomy, the bent 41-gauge needle was advanced into the subretinal space to reach the PFCL bubble. Subsequently, active aspiration of PFCL was performed. The surgical procedure was successfully performed in two patients. This technique appears to be an effective surgical approach for removing retained submacular PFCL bubble.

Perfluorodecalin Versus Densiron 68 Heavy Silicone Oil in the Management of Inferior Retinal Detachment Recurrence

BACKGROUND AND OBJECTIVE

To assess the efficacy of perfluorodecalin (PFD) or Densiron 68 heavy silicone oil (HSO) in the management of inferior complex retinal detachment recurrence.

PATIENTS AND METHODS

A retrospective, comparative consecutive case series study. Twenty-four eyes of 24 patients affected by inferior complex retinal detachment recurrence underwent pars plana vitrectomy with PFD or HSO as endotamponade. All patients recruited were affected by complicated inferior retinal detachments and had already undergone at least one vitreoretinal procedure. The primary endpoint was anatomical success with primary and secondary surgery. The secondary endpoints were functional outcome and inflammatory complications.

RESULTS

Out of 24 cases of inferior retinal detachment recurrence, 12 were tamponed with PFD (PFD group) and 12 with HSO (D68 group). Retinal reattachment rate at first surgery was 50% for the D68 group and 66.6% for the PFD group. Final reattachment rate after two or more surgical operations was 91.6% for the PFD group and 83.3% for the D68 group. Best-corrected visual acuity improved in both groups from a mean of 1.00 logMAR (20/200; standard deviation [SD]: 1) to 0.60 logMAR (20/80; SD: 0.3), and from a mean of 1.81 logMAR (20/2000; SD: 1.1) to a mean of 2.00 logMAR (20/2,000; SD:1) for the PFD and D68 groups, respectively.

CONCLUSION

Both the endotamponades used showed good results in solving inferior retinal detachment recurrence with a slightly better rate in the PFD group, but it was not statistically significant (P > .05). [Ophthalmic Surg Lasers Imaging Retina. 2019;50:274-280.].

BLINDNESS RELATED TO PRESUMED RETINAL TOXICITY AFTER USING PERFLUOROCARBON LIQUID DURING VITREORETINAL SURGERY

PURPOSE

To describe the presumed retinal toxicity after using specific batches of perfluorocarbon liquid ALA OCTA (Alamedics, Dornstadt, Germany) in pars plana vitrectomy.

METHODS

This is an observational retrospective consecutive case series analyses of patients operated on pars plana vitrectomy for retinal detachment or intraocular lens subluxation, using the 150141 or 200114 batches of perfluorocarbon liquid ALA OCTA as assistance during the surgery in a single center. Patients were included in this report if they manifested retinal toxicity signs throughout the follow-up, such as retinal and retinal pigment epithelium atrophy, disk paleness, and intensive macular fibrosis. Spectral domain optical coherence tomography (Spectralis; Heidelberg Engineering, Heidelberg, Germany) and Ultra-Wide Field 200° retinal camera (Optos P200Tx; Optos, Scotland, United Kingdom) images, electrophysiological tests, and visual fields were performed to analyze the retinal structure and functionality.

RESULTS

Seven of 80 patients showed all the described signs of toxicity, after a mean follow-up of 34.29 days (range: 10-87) since surgery. Four patients needed a second pars plana vitrectomy because of tractional retinal detachment and proliferative vitreoretinopathy, and two of them underwent a third surgery because of redetachment. All patients experienced amaurosis or central scotoma, with a final best-corrected visual acuity ranging from 20/200 to light perception.

CONCLUSION

Presumed toxic batches of perfluorocarbon liquid may cause massive retinal toxicity. A rapid suspicion, a correct traceability of surgical products, and informing health authorities are fundamental to prevent further cases of toxicity.

Clinical and OCT Findings in a Case of a Presumed Perfluorooctane Retinal Acute Toxicity

Retinal acute toxicity may be produced by several etiologies. Iatrogenic toxicity is one of the most-feared complications related to vitreoretinal surgery. The authors report a case of retinal acute toxicity due to the use of perfluorooctane during an uneventful retinal detachment surgery done elsewhere. The aim of this report is to describe the clinical and optical coherence tomography features of this complication, which unfortunately occurred in more than 100 cases in Spain. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:460-462.].

Repeated subretinal surgery and removal of subretinal decalin is well tolerated - evidence from a porcine model

Purpose

Subretinal perfluorocarbon liquid (PFCL) is a serious complication that can occur after retinal detachment repair. It is possible to remove the PFCL surgically, but retinal damage related to the procedure is unknown. Also, increasing interest in subretinal treatment makes it relevant to examine the functional and morphological consequences of repeated subretinal manipulation. We hypothesized that PFCL in a porcine model can be injected in the subretinal space and removed with minimal effect on retinal structure and function.

Methods

The left eyes of ten healthy three-month-old female domestic pigs were included. Multifocal electroretinograms (mfERG) were recorded before surgery. Following vitrectomy, a PFCL bleb (decalin) was injected subretinally using a 41G cannula. After 14 days the decalin was removed through a 41G cannula in combination with a 2 ml syringe and an intermediate flexible tube. Two weeks after removal, a control mfERG was recorded, the pigs were enucleated and sacrificed and eyes were examined histologically. All statistics were carried out with a paired t-test in SAS Enterprise Guide 7.1® (SAS Institute Inc., Cary, NC, USA).

Results

There was no significant difference in mfERG amplitude ratio (left/right eye) between baseline and recordings two weeks after removal of decalin (P1 (M = 0.26, SD = 0.80, p = 0.39), second order kernel (M = −0.18, SD = 0.86, p = 0.57), Direct Response (M = 0.39, SD = 0.61, p = 0.12) or Induced Component (M = −0.03, SD = 0.40, p = 0.80)). Histologically, the photoreceptor outer segments were minimally affected. Otherwise the retina was normal 14 days after removal of decalin. In four pigs the subretinal decalin displaced inferiorly and was no longer accessible for removal.

Conclusion

Subretinal decalin can be removed within 14 days without lasting retinal damage. Decalin is a heavy liquid where the risk of displacement is high. Future studies using PFCLs to control duration of an experimental retinal separation should focus on PFCLs that are isodense to the vitreus body.

Reversible Corneal Toxicity of Retained Intracameral Perfluoro-n-octane

A 58-year-old female presented with intracameral retained perfluoro-n-octane (PFO) following previous retinal reattachment surgery. After 4 years of follow-up without related sequelae, the patient complained of a gradual decrease in vision secondary to corneal edema with whitish corneal precipitate inferiorly corresponding to the area of retained PFO. Three weeks after anterior chamber washout, corneal edema resolved and the patient obtained 20/40 visual acuity. Even though PFO considered to have a relatively good safety profile, early anterior chamber washout may prevent corneal toxicity and avoid later persistent corneal decompensation.

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.

Tamponade in the surgical management of retinal detachment

Despite treatment advances, rhegmatogenous retinal detachment (RD) can have poor visual outcomes even with prompt and appropriate therapy. Pars plana vitrectomy is a leading management modality for the treatment of RD. This procedure is generally accompanied by the use of internal tamponade. Various gases and silicone oils may yield beneficial outcomes. Heavy silicone oils have been approved in some European nations but are not available in the USA. Different tamponade agents have unique benefits and risks, and choice of the agent should be individualized according to the characteristics of the patient and RD, as well as perioperative and postoperative factors.

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.

Experimental measure of retinal impact force resulting from intraocular foreign body dropped onto retina through media of differing viscosity

BACKGROUND

To evaluate and compare the perfluorocarbon liquid, silicone oil, and viscoelastic against standard saline, in their ability to dampen the impact force of a foreign body, dropped within the eye. In an experimental surgical model in where cohesive and adhesive forces of the substances are not enough to float heavy-than-water foreign bodies.

METHODS

A model of ophthalmic surgery was constructed. A BB pellet was dropped from 24 mm onto a force transducer through four different fluids: balanced salt solution, perfluoro-n-octane, viscoelastic, and silicone oil. The impact energy (force) for each case was measured and recorded by the force transducer. The mean force of impact for each fluid was compared using the Student t-test.

RESULTS

Silicone oil resulted in the lowest force of impact. Both silicone oil and viscoelastic dampened the impact an order of magnitude more than perfluoro-n-octane and balanced salt solution.

CONCLUSIONS

Silicone oil and viscoelastic cushioned the force from a dropped BB. They may be useful adjuncts to prevent iatrogenic retinal injury during vitrectomy for intraocular foreign body removal.