Retinal detachment and degeneration in response to subretinal perfluorodecalin in rabbit eyes

Why Perfluorocarbon nanoparticles encounter bottlenecks in clinical translation despite promising oxygen carriers?

Artificial Oxygen Carriers (AOCs) have emerged as ground-breaking biomedical solutions, showcasing tremendous potential for enhancing human health and saving lives. Perfluorocarbon (PFC)-based AOCs, in particular, have garnered significant interest among researchers, leading to numerous clinical trials since the 1980 s. However, despite decades of exploration, the success rate has remained notably limited. This comprehensive review article delves into the landscape of clinical trials involving PFC compounds, shedding light on the challenges and factors contributing to the lack of clinical success with PFC nanoparticles till date. By scrutinizing the existing trials, the article aims to uncover the underlying issues like pharmacological side effects of the PFC and the nanomaterials used for the designing, complex formulation strategy and poor clinical trial designs of the formulation. More over each generation of the PFC formulation were discussed with details for their failure in the clinical trials limitations that block the path of PFC-based AOCs' full potential. Furthermore, the review emphasizes a forward-looking approach by outlining the future pathways and strategies essential for achieving success in clinical trials. AOCs require advanced yet biocompatible single-componentformulations. The new trend might be a novel drug delivery technique, like gel emulsion or reverse PFC emulsion with fluoro surfactants. Most importantly, well-planned clinical trials may end in a success story.

Iatrogenic Paracentral Visual Field Defect After Pars Plana Vitrectomy for Macula-On Retinal Detachment Repair

Perfluorocarbon liquid (PFCL) is an important adjunct in pars plana vitrectomy (PPV) for complex retinal detachment (RD). Complete removal of PFCL is critical to prevent retinal inflammation and cellular toxicity, but removal is not risk-free. We report a case of a new postoperative onset paracentral visual field defect after PPV with PFCL use for treatment of a macula-on RD. We present pre- and postoperative imaging that suggests a likely perioperative iatrogenic cause. [Ophthalmic Surg Lasers Imaging Retina 2022;53:644-646.].

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.

Efficacy and Safety of Vitrectomy without Using Perfluorocarbon Liquids and Drainage Retinotomy Associated with Postoperative Positioning Based on Residual Subretinal Fluid for Rhegmatogenous Retinal Detachment

Medical records of 75 eyes from 75 consecutive patients with uncomplicated rhegmatogenous retinal detachment (RRD) who underwent pars plana vitrectomy (PPV) were analyzed. Inclusion criteria were patients with RRD who underwent primary 23- or 25-gauge PPV with air, gas, or SiO tamponade and performed by a single surgeon, no use of perfluorocarbon liquids (PFCL) and drainage retinotomy, and follow-up ≥ six months. Exclusion criteria were patients who underwent previous vitreoretinal surgery, proliferative vitreoretinopathy (PVR) more than grade B, giant tears, and encircling band associated with PPV. The main endpoint was the anatomical retinal reattachment rate after a single surgical procedure. Secondary endpoints were best-corrected visual acuity (BCVA), postoperative retinal displacement, and intraoperative and/or postoperative complications. Primary anatomical success was achieved in 97.3% of cases using this modified surgical procedure. Retinal slippage occurred only in 28.2% of patients and it was not observed in all cases of macula-on RRD. The mean logMAR of the BCVA significantly improved in 92% of patients and no intraoperative complications were observed. The results suggest that complete subretinal liquid drainage is not mandatory for all RRD cases treated with PPV and that using PFCL and performing a drainage retinotomy are not essential in eyes with primary RRD and PVR less than grade B. Postoperative positioning after PPV for uncomplicated RRD based on the presence or absence of residual subretinal fluid at the end of surgery could limit the occurrence of postoperative retinal displacement, while promoting patient compliance.

Natural History of a Large Bubble of Migratory Submacular Perfluorocarbon

Purpose

To report the natural history of a large bubble of perfluorocarbon liquid (PFCL) in a parafoveal subretinal position which was monitored using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). The bubble of PFCL was removed when it migrated to the subfoveal position; outcome after removal is also reported.

Observation

A 62-year-old male, after repair of a giant retinal tear (GRT) detachment, regained Snellen acuity of 6/18 from preoperative vision of CF at 1 meter. A large bubble of subretinal PFCL was in the superior parafoveal area. For 18 months, the PFCL bubble was monitored using OCT and OCTA until it migrated into the subfoveal position after 22 months, coinciding with a decrease in vision to 6/36. Surgical removal of subfoveal PFCL was performed. This involved detachment of the foveomacular, epiretinal membrane (ERM) peel (complicated by iatrogenic macular hole (MH) formation), intravitreal injection of PFCL to displace subretinal PFCL to the periphery, creation of an inverted internal limiting membrane (ILM) flap to repair the MH and air exchange. Postoperative vision remained 6/36. His postoperative OCT showed significant loss of subfoveal outer retina. On OCTA, the superficial and deep vascular plexi and choriocapillaris appeared to be intact after the removal of the subfoveal PFCL.

Conclusion and Importance

This report suggests that a large superior parafoveal bubble of PFCL may take as much as 18 months to migrate to the subfoveal position. Before this time, vision does not appear to be affected, though macular edema is present. Therefore, removal of the PFCL can be delayed until a convenient time for surgeon and patient. A large bubble of parafoveal PFCL ought to be removed before migrating to a subfoveal position and vision loss, since its removal will reduce the risk of outer retina loss.

Release and extraction of retained subfoveal perfluorocarbon liquid facilitated by subretinal BSS, vibration, and gravity: a case report

Background

Perfluorocarbon liquid (PFCL) is an effective surgical adjuvant in performing vitrectomy for severe vitreoretinal pathologies such as proliferative vitreoretinopathy and giant retinal tears. However, subretinal retention of PFCL can occur postoperatively and retained PFCL causes severe visual disorders, particularly when PFCL was retained under the fovea. Although several procedures have been proposed for subfoveal PFCL removal, such as direct aspiration or submacular injection of balanced salt solution (BSS) to dislodge the subfoveal PFCL, the retinal damage associated with these procedures has been a major problem. Here, we report a case of subfoveal retention of PFCL for which we performed a novel surgical technique that attempts to minimize retinal damage.

Case presentation

A 69-year-old man presented with subfoveal retained PFCL after surgery for retinal detachment. To remove the retained PFCL, the internal limiting membrane overlying the subretinal injection site is first peeled to allow low-pressure (8 psi) transretinal BSS infusion, using a 41-gauge cannula, to slowly detach the macula. A small drainage retinotomy is created with the diathermy tip at the inferior position of the macular bleb, sized to be slightly wider than that of the PFCL droplet. The head of the bed is then raised, and the surgeon gently vibrates the patient’s head to release the PFCL droplet to allow it to migrate inferiorly towards the drainage retinotomy. The bed is returned to the horizontal position, and the PFCL, now on the retinal surface, can be aspirated. The subfoveal PFCL is removed while minimizing iatrogenic foveal and macular damage. One month after PFCL removal, the foveal structure showed partial recovery on optical coherence tomography, and BCVA improved to 20/40.

Conclusion

Creating a macular bleb with low infusion pressure and using vibrational forces and gravity to migrate the PFCL towards a retinotomy can be considered as a relatively atraumatic technique to remove subfoveal retained PFCL.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s12886-020-01698-1.

Chorioretinal Toxicity of Perfluorooctane (Ala Octa): Results From 48 Surgical Procedures in Geneva

PURPOSE

To compare outcomes of patient who underwent surgery using perfluorooctane (PFO; C₈F₁₈; Ala Octa) with those who underwent surgery with perfluorodecalin (F-Decalin).

DESIGN

Retrospective, consecutive, comparative, interventional case series.

METHODS

A total of 48 eyes that underwent vitrectomy with PFO were compared to 29 eyes that underwent vitrectomy with perfluorodecalin. Two experienced surgeons performed vitrectomies at the Geneva University Eye Clinic. Visual acuity before, at 8 and 24 weeks after surgery, was documented, and spectral domain optical coherence tomography (SD-OCT) images were analyzed for abnormalities.

RESULTS

Two patients experienced severe retinal toxicity, including 1 with severe vision loss. However, no statistical differences in VA were observed between the PFO and perfluorodecalin patients. Analysis of SD-OCT images showed differences in occurrence of several abnormalities, for example, inner segment-outer segment alterations were found in 60.4% of eyes treated with PFO and in 10.3% of perfluorodecalin-treated eyes; retinal atrophic areas were found in 41.7% of PFO and in none of the perfluorodecalin eyes; inner limiting membrane contraction was found in 58.4% of PFO and in none of perfluorodecalin eyes; inner retina cystic alterations were found in 58.3% of PFO eyes and 17.2% of perfluorodecalin eyes; outer retina cystic alterations were found in 39.6% of PFO eyes and 13.8% of perfluorodecalin eyes; retinal holes were found in 14.6% of PFO eyes and in none of the perfluorodecalin eyes; and outer retinal inclusions were found in 20.8% of PFO eyes and in 3.45% of perfluorodecalin eyes.

CONCLUSIONS

Perfluorooctane caused significantly more toxic damage than perfluorodecalin. Special consideration should be given to develop a central European Union (EU) control agency for medical devices and to reevaluate safety procedures currently accepted by the EU and International Organization for Standardization for intraocular surgery.

Submacular perfluorocarbon liquid: long-term follow-up

PURPOSE

To report the long-term follow-up of patients with inadvertent retained submacular perfluorocarbon liquid (PFCL) bubbles after vitrectomy surgery.

BACKGROUND

PFCL has unique chemical and physical features which facilitate displacement of subretinal fluid from central toward periphery allowing intraoperative reattachment of the mobile retina and manipulation of the anterior part of the detached retina without performing drainage retinotomy. Despite these advantages, PFCL droplets may be inadvertently retained in the submacular space.

METHODS

A retrospective case series study was conducted. We reviewed 1224 consecutive patients who had undergone primary pars plana vitrectomy at one vitreoretinal center operated by single surgeon (Hammouda Ghoraba). Chart review was performed to identify patients and procedural factors that could predispose to retained submacular PFCL with anatomical and functional outcomes with follow-up at least 18 months.

RESULTS

The retina was completely attached in 97% of eyes where PFCL was used after one or two vitrectomy surgeries. Submacular PFCL was found in 12 (0.98%) eyes. There was no statistical difference between perfluorodecalin and perfluoro-n-octane as regards retention rate. The possible risk factors associated with submacular retention of PFCL phenomenon are the presence of post-equatorial retinal breaks in six patients (50%) and large retinal break (2-3 clock hours) in three patients (25%).

CONCLUSIONS

Submacular PFC migration occurs in nearly 1% of cases when it is used. It occurred in cases of RRD with post-equatorial or large breaks. Using perfluoro-n-octane or perfluorodecalin had no statistical difference. Different behaviors of submacular PFC droplets occurred. Some cases of small submacular PFC droplets maintained fair VA for a long period.

Subretinal surgery: functional and histological consequences of entry into the subretinal space

BACKGROUND AND OBJECTIVES

Gene-therapy, stem-cell transplantation and surgical robots hold the potential for treatment of currently untreatable retinal degenerative diseases. All of the techniques require entry into the subretinal space, which is a potential space located between the retina and the retinal pigment epithelium (RPE). Knowledge about obstacles and critical steps in relation to subretinal procedures is therefore needed. This thesis explores the functional and histological consequences of separation of the retina from the RPE, extensive RPE damage, a large cut in the retina (retinotomy) and RPE phagocytosis in a porcine model.

METHODS

Experiments were performed in 106 female domestic pigs of Danish landrace distributed over five studies. Under general anesthesia, different procedures for expansion of the subretinal space were conducted. Outcomes were visual function measured electrophysiologically with multifocal electroretinogram (mfERG) and retinal morphology examined histologically. Study I: The effect of anesthesia on mfERG was examined by repeated recordings for 3 hr in isoflurane or propofol anesthesia. Outcome was mfERG amplitude. Study II: Consequences of a large separation of the photoreceptors from the RPE were examined by injecting a perfluorocarbon-liquid (decalin) into the subretinal space. Two weeks after, in a second surgery, decalin was withdrawn. Outcomes were mfERG and histology 4 weeks after decalin injection. Study III: Extensive RPE damage was examined by expanding the subretinal space with saline and removing large sheets of RPE-cells through a retinotomy. Outcomes were mfERG and histology 2, 4 and 6 weeks after the procedure. Study IV: Consequences of a large retinotomy were examined by similar procedures as in Study III, but in study IV only a few RPE cells were removed. Outcomes were mfERG and histology 2 and 6 weeks after surgery. Study V: Clearance of the subretinal space was examined by injecting fluorescent latex beads of various sizes into the subretinal space. Outcome was histologic location of the beads at different time intervals after the procedure.

RESULTS

Study I: MfERG amplitudes decreased linearly as a function of time in propofol or isoflurane anesthesia. Duration of mfERG recording could be decreased without compromising quality, and thereby could time in anesthesia be reduced. Study II: MfERG and histology remained normal after reattachment of a large and 2-week long separation of the photoreceptors and RPE. Repeated entry into the subretinal space was well tolerated. Fluid injection into the subretinal space constitutes a risk of RPE-damage. Study III: Removal of large sheets of retinal pigment epithelial cells triggered a widespread rhegmatogenous-like retinal detachment resulting in visual loss. Study IV: A large retinotomy with limited damage of the RPE was well tolerated, and visual function was preserved. Study V: Subretinal latex beads up to 4 μm were phagocytosed by the RPE and passed into the sub-RPE space. Beads up to 2 μm travelled further through the Bruch's membrane and were found in the choroid, sclera and inside blood vessels.

CONCLUSION

A large expansion of the subretinal space, repeated entry, a large retinotomy and limited RPE damage is well tolerated and retinal function is preserved. Subretinal injection of fluid can damage the RPE and extensive RPE damage can induce a rhegmatogenous-like retinal detachment with loss of visual function. Foreign substances exit the subretinal space and can reach the systemic circulation.

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.

Air tamponade and without heavy liquid usage in pars plana vitrectomy for rhegmatogenous retinal detachment repair

AIM

To report the results of rhegmatogenous retinal detachment (RRD) repair after pars plana vitrectomy (PPV) without operative use of heavy liquid, and utilizing air tamponade in selected cases.

METHODS

RRD patients without severity of proliferative vitreoretinopathy C₂ or more underwent PPV without operative use of heavy liquid, and utilizing air tamponade were consecutively enrolled. Alternative postoperative facedown position or lateral position was required for 3-5d.

RESULTS

Totally 36 eyes of 36 patients (24 males, 66.7%) aged 53.8±10.9y underwent this modified surgery. The mean number of retinal break was 2.1±1.3. Most of the eyes (29, 80.6%) had retinal detachment involving more than one quadrant. Twenty-two (61.1%) eyes with cataract had combined phacoemulsification and intraocular lens implantation. The mean follow up time was 4.6±1.8mo. Two eyes with retinal redetachment underwent a second retinal repair surgery with silicone oil tamponade, yielding the primary reattachment rate to 94.4% (34/36). Six (16.7%) eyes had intraocular pressure higher than 25 mm Hg. The visual acuity (logMAR) improved from 0.98±0.74 preoperatively to 0.52±0.31 postoperatively (P<0.001).

CONCLUSION

The success rate of this modified retinal repair surgery is comparable with traditional surgery. This technique can be considered for certain retinal detachment patients, since its apparent advantages included lower surgical complications, reduced surgery expenditure, shorter time for postoperative facedown position, and avoiding silicone oil removal surgery.

Management of Subfoveal Perfluorocarbon Liquid: A Review

Perfluorocarbon liquid (PFCL) has been widely used in vitreoretinal surgeries, especially in retinal detachment treatment. A prominent complication of intraoperative PFCL application is inadvertent subretinal PFCL retention. Subfoveal PFCL, even in small amounts, receives much attention due to its potential side effect on the macular structure and function. Whether to observe with follow-up or to deal with surgery is often an intractable problem in the management of subfoveal PFCL. Safety and necessity are the 2 key issues in considering surgical treatment, that is, can we avoid surgically induced macular injury and will surgery be beneficial for the recovery of vision? Herein, the authors review sub-foveal PFCL retention with its risk factors, morphological manifestations, pathological studies, clinical natural consequences, and different surgical methods with their outcomes. Analysis of the existing literature shows that visual acuity improved significantly after subfoveal PFCL removal or displacement and was positively correlated with visual acuity before the operation.

Clinical outcomes of endoscope-assisted vitrectomy for treatment of rhegmatogenous retinal detachment

Summary

We evaluated the clinical outcomes for ophthalmic endoscope-assisted vitrectomy in consecutive patients with uncomplicated rhegmatogenous retinal detachment (RRD). The primary success rate was 98.4% (125/127) without performing a posterior drainage retinotomy or using perfluorocarbon liquids (PFCL) for subretinal fluid drainage.

Purpose

To investigate the clinical outcomes of endoscope-assisted vitrectomy in patients with uncomplicated RRD.

Methods

We examined 127 eyes from consecutive patients who underwent repair of RRD by 23- or 25-gauge endoscope-assisted vitrectomy, with a minimum follow-up of 3 months. Eyes with the following criteria were excluded: Giant retinal tears, grade C proliferative vitreoretinopathy, dense vitreous hemorrhage, retinal detachment secondary to other ocular diseases, and prior retinal or vitreous surgery. All cases underwent subretinal fluid drainage, endolaser photocoagulation and fundus inspection were performed under ophthalmic endoscopic observation. Success rate, visual acuity, surgery time and complications were evaluated.

Results

Primary and final success rate was 98.4% (125/127) and 100% (127/127), respectively, Surgery time was 59.6±26.3 minutes. The best-corrected visual acuity significantly improved from 20/100 to 20/20 (P<0.0001). There were 2 cases (1.6%) of creation of a peripheral drainage retinotomy and 4 cases (3.1%) of using PFCL to suppress movement of the detached retina, but there were no cases of creation of a posterior drainage retinotomy or using PFCL for subretinal fluid drainage. There was 1 case of presumed endophthalmitis after surgery. There were 12 hypotonous cases at postoperative day 1 and one of them needed additional scleral sutures at postoperative day 4 for prolonged hypotony.

Conclusion

The present study demonstrated the efficacy of endoscope-assisted vitrectomy for patients with uncomplicated RRD. To perform endoscope-assisted vitrectomy safely, sufficient closure of sclerotomies is necessary at the end of surgery.

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.

In vitro experiment to elucidate the mechanism of the 'soft shell technique' for preventing subretinal migration of perfluoro-octane

AIM

Perfluorocarbon liquid (PFCL) can migrate into subretinal space in detached and stiffened retina with open holes during vitreoretinal surgery. An innovative 'soft shell' technique was introduced to reduce the complication using hyaluronate (HA) to 'cover' the retinal hole. This study aims to study the effectiveness of this technique in vitro.

METHODS

Ex vivo porcine retina was mounted on a transwell insert. Beneath the retina was an aqueous solution. Two retinal holes were made using needle punctures. One of the two retinal holes was covered with HA. Perfluoro-n-octane (PFO) was added above the retina incrementally using a syringe pump. The height of PFO required to cause the migration of PFO through the retinal holes was measured. The 'pendant drop' method was carried out to measure the interfacial tensions between the PFO and aqueous, and between PFO and four different concentrations of HA solution.

RESULTS

A statistically higher PFO level was required to cause the migration of PFO through the retinal hole with HA coating than without HA coating (Tobit regression with p<0.05). The use of HA was associated with 2.39-fold increase in hydrostatic pressure before the collapse of the PFO interface at the retinal holes. The interfacial tension between PFO and HA solution with concentrations of 0.05%, 0.25%, 0.5% and 1% were 54.2±0.6, 55.3±0.6, 59.5±1.5 and 68.3±1.3 mN/m, respectively (mean±SD). The interfacial tension between PFO and aqueous with 1% HA coating (68.3±1.3 mN/m) was significantly higher than that without (37.4±3.4 mN/m) (p<0.05).

CONCLUSIONS

The interfacial tension between HA and PFO is higher than that between aqueous and PFO. This is a plausible physical explanation of how the 'soft shell' technique might work to prevent subretinal migration of PFCL.

25-Gauge Vitrectomy and Incomplete Drainage of Subretinal Fluid for the Treatment of Primary Rhegmatogenous Retinal Detachment

BACKGROUND AND OBJECTIVE

To evaluate the anatomical and functional results of 25-gauge (G) vitrectomy with incomplete drainage of subretinal fluid for the treatment of primary rhegmatogenous retinal detachment.

PATIENTS AND METHODS

A retrospective, noncomparative interventional case series including 100 consecutive patients who underwent 25-G vitrectomy, incomplete drainage of subretinal fluid, cryolaser or endolaser, and SF6 gas tamponade for the treatment of primary rhegmatogenous retinal detachment was performed.

RESULTS

Fifty-six percent of retinal detachments were macula-on and 44% were macula-off. Fifty-six percent of patients were phakic and 44% were pseudophakic. Primary anatomical success rate was 94%, and the final success rate was 100%. Mean preoperative visual acuity was 0.75 logMAR, and mean postoperative visual acuity was 0.39 log-MAR (P < .001).

CONCLUSION

Incomplete drainage of subretinal fluid during vitrectomy for the treatment of primary rhegmatogenous retinal detachment does not seem to influence the anatomical success rate. On the contrary, it minimizes the surgical maneuvers, thus reducing perioperative complications.

Subretinal fluid drainage via original retinal breaks for rhegmatogenous retinal detachment

OBJECTIVE

To evaluate the outcome of vitrectomy using only original retinal breaks for subretinal fluid (SRF) drainage during the repair of primary rhegmatogenous retinal detachment (RRD).

DESIGN

A retrospective consecutive interventional case series.

PARTICIPANTS

A consecutive series of 112 eyes of 112 patients.

METHODS

Patients underwent 23-gauge vitrectomy without the use of posterior retinotomy and perfluorocarbon liquids for uncomplicated primary RRD at Osaka City University Hospital between September 2007 and March 2011. Exclusion criteria included eyes with giant retinal tears, grade C2 or worse proliferative vitreoretinopathy (PVR), ocular trauma, and the presence of other vitreoretinal diseases.

RESULTS

Single-operation success rate was 92.9%, whereas final anatomical success rate was 100%. Median visual acuity improved significantly from the preoperative logMAR of 0.51 ± 0.78 to the postoperative logMAR of 0.03 ± 0.26 (p < 0.01). No significant differences were observed for the single-operation success rate between the 62 eyes (95.2%) in which some SRF remained at the end of the operation and the rest of the 50 eyes (90.0%, p = 1.000) in which the SRF had been completely aspirated. Complications included transient intraocular pressure rise (12 eyes, 10.7%), epiretinal membrane (5 eyes, 4.5%), and PVR (1 eye, 0.9%). Ocular hypotony and endophthalmitis were not observed.

CONCLUSIONS

Uncomplicated primary RRD can be successfully repaired by performing vitrectomy using only the original retinal breaks for SRF drainage. In addition, successful outcomes are not dependent on achieving complete reattachment of the retina throughout the fundus.

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.

Surgical removal of retained subfoveal perfluorocarbon liquid through a therapeutic macular hole with intravitreal PFCL injection and gas tamponade

We report two cases of surgical removal of a retained subfoveal perfluorocarbon liquid (PFCL) bubble through a therapeutic macular hole combined with intravitreal PFCL injection and gas tamponade. Two patients underwent pars plana vitrectomy with PFCL injection for rhegmatogenous retinal detachment. In both cases, a retained subfoveal PFCL bubble was noticed postoperatively by funduscopy and optical coherence tomography. Both patients underwent surgical removal of the subfoveal PFCL through a therapeutic macular hole and gas tamponade. The therapeutic macular holes were completely closed by gas tamponade and the procedure yielded a good visual outcome (best-corrected visual acuity of 20 / 40 in both cases). In one case, additional intravitreal PFCL injection onto the macula reduced the size of the therapeutic macular hole and preserved the retinal structures in the macula. Surgical removal of a retained subfoveal PFCL bubble through a therapeutic macular hole combined with intravitreal PFCL injection and gas tamponade provides an effective treatment option.

Unanticipated vision loss after pars plana vitrectomy

Although advances in vitreoretinal surgical techniques and technology have helped to minimize the risks associated with surgical manipulation of the retina, retinal pigment epithelium, and optic nerve, unanticipated or unexplained visual loss still occurs. We review causes of vision loss encountered after pars plana vitrectomy, including retinal toxicities, vascular events, and optic neuropathies, and we suggest strategies to limit or prevent them.

[Perfluorocarbon liquids and vitreoretinal surgery in 2011]

Perfluorocarbon liquids (PFCLs) are one of the most innovative recent tools for vitreoretinal surgery. PFCLs are characterized by their number of carbon atoms, which has an impact on the density, viscosity, surface tension, vapor pressure, the boiling point, and the refraction index. PFCLs are routinely used because of their high gravity (double that of water) and their low viscosity. Furthermore, they are immiscible in water, optically clear with refraction indices similar to that of water, allowing visualization of an interface between the PFCL and saline. The use of intravitreally injected liquid PFCLs as adjunctive agents to vitreoretinal surgery plays an important role in facilitating retinal reattachment, especially in cases of giant retinal tear, trauma, and/or proliferative vitreoretinopathy. PFCLs are also used as intraoperative instruments to re-establish intraocular volume, assist in separating membranes adherent to the retina (in proliferative diabetic retinopathy, for example), and manage the dislocated crystalline lens and intraocular lens.

Three-Dimensional OCT Features of Perfluorocarbon Liquid Trapped Under the Fovea

Two patients with perfluorocarbon liquid (PFCL) trapped under the fovea after vitreoretinal surgery for repair of rhegmatogenous retinal detachment were reported. PFCL was used to flatten the retina intraoperatively. Postoperatively, a bubble of PFCL was trapped under the fovea and was removed surgically in both patients. Three-dimensional and orthogonal optical coherence tomography (OCT) features in both cases are reported. Three-dimensional OCT features in our two cases were retinal pigment epithelium (RPE) pigment disorganization, disruption of both external limiting membrane backreflection line and reflectivity of the photoreceptor inner and outer segment junction, and hyperreflectivity at the base of the PFCL bubble corresponding to the zone of interface of PFCL and damaged RPE. Trapped subfoveal PFCL should be removed surgically as soon as possible to prevent structural retinal damage. Spectral domain OCT is a useful tool to demonstrate subclinical structural damage of the neurosensory retina and RPE.

RISK FACTORS FOR RETENTION OF SUBRETINAL PERFLUOROCARBON LIQUID IN VITREORETINAL SURGERY

PURPOSE

To analyze factors that may lead to inadvertent subretinal retention of perfluorocarbon liquid (PFCL) after vitreoretinal surgery and compare surgical outcomes and complications associated with these events.

DESIGN

Consecutive retrospective study.

METHODS

The authors retrospectively reviewed the charts of 72 vitreoretinal surgeries using intraoperative PFCL and its removal through fluid-air exchange and subsequent tamponade. Indications for surgery included trauma, retinal detachment, giant retinal tear, and submacular hemorrhage. Most interventions studied had significant amounts of proliferative vitreoretinopathy and were required after failed or complicated previous vitreoretinal surgery.

MAIN OUTCOME MEASURES

Analysis was focused on the occurrence of subretinal retention of PFCL during different surgical procedures and techniques, indications, anatomic and visual results, and complications.

RESULTS

At the last follow-up, the retina was completely attached in 97% of eyes treated with PFCL after 1 or 2 vitrectomies. Subretinal PFCL was found in 8 (11.1%) eyes. There was no statistical difference in the retention rate for perfluorodecalin and perfluoro-n-octane. The factor most significantly associated with subretinal retention of PFCL was the presence and large size of a peripheral retinotomy. All cases of subretinal PFCL had a retinotomy of 120 degrees or larger. The average retinotomy size in these cases was 259 degrees . Subretinal PFCL was found in 40% of eyes with a 360 degrees retinotomy. Small and medium-sized retinal breaks were not associated with PFCL retention. Another surgical procedure that correlated significantly with subretinal PFCL was lack of saline rinse during fluid-air exchange. Only 1 of the 23 eyes that were rinsed had subretinal PFCL, although many had large retinotomies.

CONCLUSION

Subretinal PFCL retention is most likely to occur in eyes with large peripheral retinotomies, especially if 360 degrees . Saline rinse seems to be useful in the prevention of subretinal PFCL. The presence of subretinal PFCL does not seem to affect visual and anatomic success when located outside the macula, at least during an intermediate period of follow-up.

Perfluorodecalin modifies the pattern of cell arrangement and induces loss of neurites in rat retinal cultures

Perfluorodecalin (PFD), a high specific weight, water-immiscible perfluorocarbon, previously studied as a potential blood substitute, now is used widely in the field of ophthalmic surgery as a tool for maneuvering intraocular tissues and as a short- or medium-term vitreous substitute. In in vivo experiments, several types of lesions in retinal tissue have been described in conjunction with long-term PFD treatment. To better evaluate the biological effects of PFD on retinal cells, we tested it on primary cultures of rat retina seeded on special cyclopore wells that allow the culture to be fed from the bottom side while the top side is in contact with the water-immiscible compound. We found that PFD changed the pattern of cell arrangement and induced loss of neurites. The modification of cell arrangement was less evident at the periphery of the wells where the amount of PFD, and consequently the pressure exerted, was lower. This observation suggests that the changes may be due more to a physical than to a toxic effect of PFD.

Safety evaluation of perfluoropolyethers, liquid polymers used in barrier creams and other skin-care products

Fomblin HC products are a 'family' of high-purity perfluoropolyethers manufactured for barrier cream and other personal care applications which involve direct application to the skin. To confirm the safety of such use, representative Fomblin HC products were tested in experimental animals for acute toxicity, primary and repeated insult irritancy, sensitization and photosensitization, subacute oral toxicity and comedogenicity; mutagenicity was examined in vitro, and irritancy or sensitization was also investigated on human skin (in patch tests with volunteers). A high molecular weight Fomblin HC only was tested in rats for subacute oral toxicity and in man for dermal effects. Single oral doses of 15 g/kg body weight were without evident toxicity to rats, as were single dermal applications or an ip injection at 5 g/kg. No primary irritant action was seen in rabbits or man, and similarly there was no evidence of skin sensitization or photosensitization in guinea pigs, or sensitization in man. No mutagenic action on Salmonella strains of tester bacteria was seen. In repeat dose irritancy or oral toxicity tests in rabbits or rats, no adverse effects of Fomblin HC products were noted; in particular, daily oral administration (1000 mg/kg/day) to rats over 28 days produced no significant reaction. No comedogenic action was found. From the known chemistry of the perfluoropolyethers, the test programme reported here and the limited published data, it is concluded that the intended use of Fomblin HC products in formulations applied to human skin has a high margin of safety.

Perfluorocarbon liquids in ophthalmology

Perfluorocarbon liquids have been used to facilitate surgery in a wide variety of conditions, including proliferative vitreoretinopathy, giant retinal tears, drainage of suprachoroidal hemorrhages, diabetic traction, retinal detachments with a rhegmatogenous component, dislocated crystalline or intraocular lenses, and retinal detachment associated with choroidal coloboma. The clarity of perfluorocarbon liquids, with a refractive index close to that of water, allows the use of a conventional contact lens for vitreous surgery while the low viscosity facilitates tissue manipulation, injection, and removal. All perfluorocarbon liquids when used as tamponading agents can compress and disorganize the retina. This "toxicity" is a physical effect rather than chemical toxicity and depends upon the amount of perfluorocarbon liquid injected. Perfluorocarbon liquids are not tolerated in the anterior chamber, causing corneal edema within 2-3 days at the site of contact.

Fluid air exchange in vitreo retinal surgery

This study evaluates the efficiency of fluid-air exchange on the reattachment of the retina and clarifies the possibility that a posterior retinotomy is a cause for intra- and postoperative complications. A consecutive series of 211 eyes with retinal detachments due to P.V.R. (47%), diabetic traction, perforating trauma, macular hole or giant tears is presented. All eyes underwent pars plana vitrectomy, fluid-air exchange, internal drainage of subretinal fluid, laser endophotocoagulation and scleral buckling of the tears; 56% of the eyes were phakic and 55% underwent a posterior retinotomy, 54% underwent tamponade with C3F8 and 46% with silicone oil. Intraoperatively the retina was completely flattened in 91% cases. The causes of incomplete reattachment were residual membranes (6.6%), poor visualization (1.4%) and suprachoroidal hemorrhage (1%). These complications were isolated as being the cause of the bad final results (p < 0.001). Postoperatively, the retina remained attached in 66% of cases after the first procedure and with further surgery in 81% (mean follow up 16 months). Best corrected visual acuity was improved in 73% of eyes, unchanged in 17%, and worse in 10%. Complications were retraction of the retinotomy site in 3 cases and peripheral choroidal hemorrhage in 4 cases. We concluded that fluid air exchange with internal subretinal fluid drainage was an efficient and safe technique even if a posterior retinotomy was necessary.