Glaucoma after pars plana vitrectomy and silicone oil injection for complicated retinal detachments

Long term outcome of Ahmed valve implantation in post -vitrectomy glaucoma patients

PurposeAssessment of the long-term surgical outcomes of AGV implantation in patients with post-vitrectomy glaucoma over a ten-year period at Rassoul Akram Hospital.MethodsAll glaucoma patients who underwent post-vitrectomy AGV implantation at Rassoul Akram Hospital between 2010 and 2020 were evaluated in this retrospective study. The major outcome measures were IOP, medication use, and overall surgical success. A complete success was defined as an IOP of 6-21 mmHg, without any loss of light perception or need for glaucoma medications, or at least a 20% decrease in IOP without the use of medications. Qualifying success was defined similarly, with the use of medications. The cumulative success rates included both qualified and complete success rates.ResultsBetween 2010 and 2020, a total of 76 patients underwent AGV implantation at Rassoul Akram Hospital, met the inclusion criteria. The average duration of follow-up was 30.41 ± 27.16 months. Among the participants, 64.5% were male, and 35.5% were female. The initial IOP readings averaged 28.39 ± 9.75 mmHg; however, the final follow-up showed a decrease to 15.21 ± 5.6 mmHg (P value < 0.01). The Kaplan-Meier survival analysis demonstrated a cumulative success rate of 92.2% at 12 months, which progressively declined to 90.0% at 24 months, 84.2% at 36 months, 69.9% at 48 months, and ultimately reached 64.5% at 60 months.ConclusionThe implantation of an Ahmed valve has proven beneficial in lowering intraocular pressure in post-vitrectomy glaucoma patients, but its efficacy is predicted to decrease with time.

Incidence and risk factors of late-onset intraocular pressure elevation after vitrectomy with silicone oil tamponade

PURPOSE

To evaluate the incidence and risk factors of late-onset intraocular pressure (IOP) elevation in patients who underwent pars plana vitrectomy with silicone oil (SO) injection for the management of various vitreoretinal pathologies.

STUDY DESIGN

A retrospective observational study.

METHODS

A single-center study involving 135 eyes of 129 patients who underwent vitrectomy with SO injections between January 2018 and May 2023 and maintained SO tamponade for ≥1 month. Eyes with prior glaucoma surgery; a history of SO injection; SO removal or exchange within a month; a follow-up period of <1 month; or those who showed IOP elevation on postoperative day 1 were excluded from the analysis. Late-onset IOP elevation was defined as IOP ≥ 21 mm Hg after postoperative day 7.

RESULTS

Late-onset IOP elevation developed in 22.2% (30/135 eyes) and the mean onset was 38.0±53.4 days (7-251 days) after surgery. In the multivariate logistic regression analysis, late-onset IOP elevation was associated with pre-existing glaucoma (odds ratio [OR], 7.16; P=0.041), longer axial length (OR, 1.40, P=0.037), and higher preoperative IOP (OR, 1.12; P=0.037). Among the patients with late-onset IOP elevation, 50% (15/30) required oral acetazolamide despite the administration of IOP-lowering eye drops. Among them, surgical intervention was required in 8 cases (53.3%).

CONCLUSION

Late-onset IOP elevation is a common complication associated with SO tamponade. Risk factors for late-onset IOP elevation are pre-existing glaucoma, longer axial length, and preoperative higher IOP. Since a substantial proportion of eyes require surgical intervention, proactive measures should be considered for effective IOP control.

Ultrasound biomicroscopy assessment of the subclinical involvement of the aqueous drainage structures after silicone oil tamponade

PURPOSE

To examine the subclinical ultrasound biomicroscopy (UBM) changes in the anterior segment (AS) of eyes after silicone oil tamponade (SOT) permanence.

METHODS

This observational study enrolled patients undergone pars plana vitrectomy for retinal detachment with SOT. UBM was performed shortly before removing the SOT from eyes without any clinically detectable emulsion/particle in the AS (i.e., the study cohort). For each subject, four radial scans of the AS were obtained circumferentially for both the study and the fellow non-operated eye (i.e., the control cohort). A region of interest (ROI) was identified in each UBM scan and the maximum, minimum, and mean echo-reflectivity were assessed using imageJ software.

RESULTS

The study enrolled 33 patients (66 eyes). Of the study eyes, 15 underwent high-density tamponade (SOX), 11 underwent 2000cSt tamponade (SO2), and seven underwent 5000cSt tamponade (SO5). Significantly higher echo-reflectivity was detected in the superior quadrants of groups SO2 and SO5 (P = 0.04 and 0.02, respectively) and in the inferior quadrant of group SOX (P < 0.01) compared to the corresponding control eyes. In group SO2, the duration of the intraocular tamponade positively correlated with the number of hyper-reflective quadrants (P < 0.01).

CONCLUSIONS

The significant relationship between SOT density and the localization of areas of increased echo-reflectivity supports the actual relationship between SOT trabecular impregnation and UBM findings, even in eyes free from visible emulsions. In the SO2 group, the duration of the intraocular SOT correlated with the extent of the involvement of the filtering structures.

One-Month Silicone Oil Tamponade Can Decrease Intraocular Complications via Reducing the Recruitment and Activation of Leukocytes in Patients with Rhegmatogenous Retinal Detachment

INTRODUCTION

The aim of the study was to compare the effects of 1-month versus routine-duration silicone oil (SO) tamponade on intraocular inflammatory cytokine levels and clinical outcomes in patients undergoing vitrectomy for rhegmatogenous retinal detachment.

METHODS

A prospective study from May 2019 to March 2022 divided patients undergoing vitrectomy into routine and early groups. Aqueous humor was sampled before SO removal to measure cytokine levels, including granulocyte-macrophage colony-stimulating factor, interferon (IFN)-γ, interleukin (IL)-4, IL-8, IL-10, IL-13, IL-17, macrophage inflammatory protein (MIP)-1α, tumor necrosis factor (TNF)-α, and IL-1α. Clinical outcomes such as SO emulsification, cataract formation, recurrent retinal detachment, corneal endothelial cell (CEC) density, and intraocular pressure were assessed. Statistical analyses were performed to evaluate differences and correlations between cytokine levels and clinical characteristics.

RESULTS

The study analyzed 48 eyes, with 28 in the routine group and 20 in the early group. The early group had significantly lower IL-8 and TNF-α levels (p = 0.006 and p = 0.013) and reduced SO emulsification (p = 0.01). A significant trend toward fewer cataract cases and higher CEC density was observed in the early group (p = 0.019 and p = 0.015). IL-8 and TNF-α levels showed positive correlations with IL-10, MIP-1α.

CONCLUSION

One-month SO tamponade significantly reduces intraocular inflammatory cytokine levels and associated complications by decreasing the recruitment and activation of leukocytes. These findings suggest that shorter SO placement durations can effectively minimize inflammation-related complications while maintaining therapeutic efficacy. Future research should focus on optimizing SO tamponade protocols and exploring the underlying mechanisms of inflammation and emulsification to enhance the safety and efficacy of vitreoretinal surgeries.

Silicone Oil Affects Fibrosis of Human Trabecular Meshwork Cells by Upregulating Ferroptosis Through a ROS/NOX4/Smad3 Axis

Purpose

Silicone oil (SiO) is commonly employed as an intravitreal tamponade to manage complex retinal detachments associated with proliferative diabetic retinopathy, trauma, or severe myopia and to facilitate retinal reattachment. Nevertheless, SiO usage is linked to several complications, notably secondary glaucoma, which constitutes a significant proportion of adverse effects. This study investigated the impact of SiO on trabecular meshwork cells, given their pivotal role in regulating aqueous humor outflow.

Methods

Human trabecular meshwork cells (HTMCs) were co-cultured with SiO. The impact on proliferation, fibrosis-related markers, and ferroptosis levels on these cells was evaluated using 5-ethynyl-2'-deoxyuridine (EdU), western blot, and immunofluorescence assays. Further gene knockdown experiments with NOX4 and Smad3 were conducted to elucidate the underlying mechanisms of SiO-induced changes.

Results

SiO intervention inhibited HTMC proliferation, upregulated fibrosis-related markers, and elevated ferroptosis levels. Gene knockdown experiments revealed that SiO-induced ferroptosis and reactive oxygen species (ROS) increase were mediated through NOX4 upregulation and Smad3 activation.

Conclusions

These findings highlight the significance of ferroptosis and the ROS/NOX4/Smad3 axis in the mechanism of SiO-induced intraocular pressure elevation. The insights gained from this study identify potential therapeutic targets to mitigate postoperative complications associated with SiO tamponade in ophthalmic surgery.

Silicone oil, an intraocular surgical adjuvant, induces retinal ferroptosis

Vitrectomy with silicone oil (SO) endotamponade is an effective treatment for vision-threatening retinal diseases. However, unexplained vision impairment has been reportedly critical side effects. Previously, we reported that the eyes with ocular toxoplasmosis showed retinal ferroptosis with the clinical sign of reduced intravitreal iron (Fe). We also found that total iron levels in sub-silicone oil fluid (SOF) in eyes with SO endotamponade were significantly reduced. We hypothesized that the cause of complications related to SO endotamponade is retinal ferroptosis and that low total iron in SOF is a secondary change that occurs similarly to the changes in ocular toxoplasmosis. In this study, we measured total iron levels in ocular fluid from patients, rabbits with SO endotamponade. Retinal iron taken up from the SOF was evaluated using laser ablation inductively coupled plasma mass spectrometry in human and rabbit eyes. Retinal ferroptosis was confirmed by immunohistochemistry of 4-hydrox-2-nonenal-modified proteins, FeRhoNox-1 staining, western blotting and RT-PCR. We found low total iron levels in the SOF, increased oxidative stress and Fe uptake from the SOF into the retinae of human and rabbit eyes, as well as decreased GPx4 expression, increased FeRhoNox-1 signals and altered Fe-related gene expression in SO-filled rabbit eyes. Of note, the target of ferroptosis was Müller cells. We generated an in vitro silicone oil-filled eye model using MIO-M1 cells (a human Müller cell line). The in vitro SO-filled eye model showed decreased GPx4 expression and increased intracellular catalytic Fe(II), an increase in ferroptosis, prevention of cell death by ferrostatin-1, a ferroptosis inhibitor, and altered Fe-related gene expression. These results indicate that the cause of complications related to SO endotamponade was the induction of retinal (Müller cell) ferroptosis, which can be prevented by ferrostatin-1.

Injectable alginate-based in situ self-healable transparent hydrogel as a vitreous substitute with a tamponading function

Retinal detachment and other vision-threatening disorders often necessitate vitreous body removal and tamponade injection for retina stabilization. Current clinical tamponades such as silicone oil and expansile gases have drawbacks, including patient discomfort and the need for secondary surgery. We introduce a transparent alginate-phenylboronic acid/polyvinyl alcohol composite hydrogel (TALPPH) as a novel vitreous substitute with tamponading capabilities. In vitro physicochemical, rheological, and optical characterization of in situ self-healable TALPPH was performed, and long-term biocompatibility was assessed in a rabbit model of vitrectomy retinal detachment. In vivo evaluations confirmed TALPPH's ability to inhibit retinal detachment recurrence and preserve rabbit vision without adverse effects. TALPPH's close resemblance to the natural vitreous body suggests potential as a vitreous tamponade substitute for future ophthalmological applications.

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

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

Prediction model for elevated intraocular pressure risk after silicone oil filling based on clinical features

Background

To evaluate risk factors and further develop prediction models for intraocular pressure elevation (IOP) after vitreoretinal surgery with silicone oil tamponade to support clinical management.

Methods

A retrospective study analyzed 1,061 eyes of 1,061 consecutive patients that presented to the Jiangsu Province Hospital between December 2015 and December 2020, the IOP was measured from the preoperative visit and at the 1-week, 1-month, 3-month, and 6-month visits, and the final postoperative visit before silicone oil removal. Four machine learning methods were used to carried out the prediction of IOP elevation: Decision Tree, Logistic Regression, Random Forest, and Gradient-Boosted Decision Trees (GBDT) based on features including demographic and clinical characteristics, preoperative factors and surgical factors. Predictors were selected based on the p-value of the univariate analysis.

Results

Elevated intraocular pressure developed in 26.01% of the eyes postoperatively. Elevated intraocular pressure primarily occurred within 1-2 weeks after surgery. Additionally, the majority of IOP values were distributed around 25-40 mmHg. GBDT utilizing features with p-values less than 0.5 from the hypothesis testing demonstrated the best predictive performance for 0.7944 in accuracy. The analysis revealed that age, sex, hypertension, diabetes, myopia, retinal detachment, lens status and biological parameters have predictive value.

Conclusion

Age, sex, hypertension, diabetes, myopia, retinal detachment, lens status and biological parameters have influence on postoperative intraocular pressure elevation for patients with silicone oil tamponade after pars plana vitrectomy. The prediction model showed promising accuracy for the occurrence of IOP elevation. This may have some reference significance for reducing the incidence of high intraocular pressure after pars plana vitrectomy combined with silicone oil filling.

Inferior implant of XEN63 Gel stent in a refractory open-angle glaucoma due to silicone oil tamponade: A case report

BACKGROUND

To discuss the efficacy of an inferior implant of XEN 63 gel stent in a patient with refractory glaucoma after trabeculectomy failure and vitreoretinal surgery with silicone oil tamponade.

CASE DESCRIPTION

We report the case of a 73-year-old man with a history of refractory open glaucoma with trabeculectomy failure. He experienced recurrent retinal detachments with silicone oil tamponade, with uncontrolled intra-ocular pressure (IOP) after silicone oil removal. Due to the presence of oil emulsion in the anterior chamber, the chosen location for XEN 63 implantation was the infero-temporal quadrant. Mild hyphema and vitreous hemorrhage were seen post-operatively, but were self-limiting. At week 1, the intraocular pressure was 8 mmHg with a well-formed bleb seen in anterior segment optical coherence tomography (AS-OCT). At 6 month follow up, the patient maintained a IOP of 12 mmHg without topical hypotensive drugs. Slit lamp examination revealed a widespread, developed bleb with no signs of inflammation.

CONCLUSION

In this case of refractory glaucoma in a vitrectomized eye with previous oil tamponade, the inferior placement of the XEN 63 gel stent delivered an adequate intraocular pressure even at 6-months follow up, with a diffuse functional infero-nasal bleb seen with AS-OCT.

Functional and structural outcomes and complications after pars plana vitrectomy for severe features of proliferative diabetic retinopathy in type 1 and type 2 diabetes mellitus

PURPOSE

To evaluate the functional and structural outcomes as well as postoperative complications after pars plana vitrectomy (PPV) for severe features of proliferative diabetic retinopathy (PDR) in type 1 and type 2 diabetes mellitus (DM) patients.

METHODS

Twenty two eyes of type 1 diabetics (DM1 group) and 27 eyes of type 2 diabetics (DM2 group) were included. Best corrected visual acuity (BCVA), intraocular pressure (IOP), postoperative structural changes in optical coherence tomography (OCT) and postoperative complications such as recurrent vitreous haemorrhage, diabetic macular oedema, secondary glaucoma and persistent tractional retinal detachment (TRD) were assessed and compared between the two groups.

RESULTS

Complete reattachment of retina was achieved in 88.9% from the DM1 group and in 95.5% from the DM2 group and remained attached in follow-up. BCVA in DM2 group was significantly lower preoperatively (p = 0.04). Mean postoperative BCVA significantly improved in both studied groups, but it was more evident in eyes of type 2 diabetics compared to type 1 diabetics. In eyes in the DM1 group there was perceptible stabilisation of BCVA. Poor visual acuity or lack of improvement in BCVA in the DM1 group was related to preoperative subretinal haemorrhage in macular region, and TRD involving macula, whereas in the DM2 group-to preoperative subretinal haemorrhage and neovascular glaucoma. The postoperative structural changes (disruption of EZ and ELM) were observed more often in DM2 group, but had the greatest impact on BCVA in eyes of type 1 DM. Complications after PPV for PDR were rare and hadn't a significant influence on the final functional outcomes in both groups.

CONCLUSIONS

Functional improvement after PPV for severe features of proliferative diabetic retinopathy were more noticeable in patients with type 2 DM. Postoperative structural changes had more negative impact on BCVA in type 1 diabetics.

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.

Silicone oil tamponade in surgical treatment of rhegmatogenous retinal detachment

The article presents a literature review regarding the use of silicone oil tamponade (ST) in rhegmatogenous retinal detachment (RRD) treatment. Vitrectomy, which produces a stable anatomical result in most patients, is currently recognized as one of the main methods of treating RRD. In complicated retinal detachments, vitrectomy is followed by ST tamponade of the vitreous cavity (VC). Despite the many benefits of ST, it carries the risk of a number of complications arising at different times after surgery. The duration of ST presence in the vitreous cavity during RRD treatment may vary substantially. The review presents ST complications, including an unexpected and hard to explain vision deterioration after silicone oil removal, and the correlation between the complications and the duration of ST presence in the vitreous cavity.

Silicone oil residual after vitrectomy for rhegmatogenous retinal detachment

OBJECTIVE

To explore the presence of residual emulsified silicone oil (SO) droplets in patients with rhegmatogenous retinal detachment (RRD) and their possible risk factors.

METHODS

Patients who underwent primary pars plana vitrectomy with SO injection for RRD and SO removal at the same eye centre were included. Approximately 10 weeks after SO removal, B-scan ultrasonography was performed, and using ImageJ, the silicone oil index (SOI) was measured, and its possible correlations with other clinical factors were explored.

RESULTS

A total of 101 eyes were included. Residual SO particles were found in all the patients (100%), and the mean SOI was 4.04% ± 5.16% (range 0.06%-19.88%). Multiple linear regression revealed that, among all the clinical factors, axial length (AL) and ocular hypertension (intraocular pressure (IOP) > 21 mmHg or the use of antiglaucoma medications) before SO removal were positively and significantly associated with the SOI (all P < 0.05). Patients with ocular hypertension after SO removal had a higher SOI, a longer SO duration, a higher IOP before SO removal and a longer AL than those without (all P < 0.05).

CONCLUSIONS

Patients with a larger AL and higher IOP before SO removal were more prone to have more residual SO droplets, which might in turn lead to an elevated IOP. In these eyes, thorough irrigation or repeated fluid-air exchange might be necessary.

Complications associated with the use of silicone oil in vitreoretinal surgery: A systemic review and meta-analysis

Silicone oil (SO) still represents the main choice for long-term intraocular tamponade in complicated vitreoretinal surgery. This review compared the complications associated with the use of SO and other vitreous substitutes after pars plana vitrectomy in patients with different underlying diseases. Meta-analysis was conducted in accordance with PRISMA guidelines. We retrieved randomized clinical trials (RCTs), retrospective case-control and cohort studies evaluating the risk of using SO, published between 1994 and 2020, conducting a computer-based search of the following databases: PubMed, Web of Science, Scopus and Embase. Primary outcome was the rate of complications such as intraocular hypertension, retinal re-detachment, unexpected vision loss or hypotony. Secondary outcome was to compare the rate of adverse events of different SO viscosities, especially emulsification. Forty-three articles were included. There were significant differences in intraocular hypertension (p = 0.0002, OR = 1.66; 95% CI = 1.27-2.18) and the rate of retinal re-detachment (p < 0.0009, OR = 0.65; 95% CI = 0.50-0.64) between SO and other agents, including placebo. However, there were no differences in other complication rates. Silicone oil (SO)-emulsification rate was non-significantly higher in low than high SO viscosity, and results from other complications were comparable in both groups. The high quality of most of the studies included in this study is noteworthy, which provides some certainty to the conclusions. Among them is the high variability of the SO residence time. The fact that ocular hypertension and not hypotension is related to SO use. A clear relationship is not found for the so-called unexplained vision loss, which affects a significant percentage of eyes. Re-detachment cases are less if SO is used and that surprisingly there does not seem to be a relationship in the percentage of emulsification between the low- and high-viscosity silicones. All these data warrant more standardized prospective studies.

Surgical Treatment in Silicone Oil-Associated Glaucoma

Glaucoma is a vision threatening, not uncommon complication of eyes that have undergone pars plana vitrectomy with silicone oil endotamponade. Although most patients respond well to medical antiglaucoma therapy, there are refractory cases where surgery is required to control the intraocular pressure. This review, following a comprehensive literature search in the Medline database, aims to present the most important surgical techniques currently in use for glaucoma associated with silicone oil endotamponade and their indication depending on the mechanism of glaucoma. In cases of pupillary block, the presence of a patent iridotomy or iridectomy must be ensured, either by laser or surgically. When silicone oil is in excess and whenever the retinal status permits it, partial or complete removal of the silicone oil should be performed. Trabeculectomy has shown higher failure rates and more complications in these cases compared to other indications, so alternate methods are warranted. For very high intraocular pressures, glaucoma drainage devices and transscleral cyclophotocoagulation are the most used options, with good efficacy and safety profiles, although rarely they may have serious complications. The Ex-PRESS mini shunt has shown excellent results and lower rates of complications. For less important IOP elevations, minimally invasive glaucoma surgery and selective laser trabeculoplasty may be used, either alone or in conjunction with other methods.

Effects of refractive accommodation on subfoveal choroidal thickness in silicone oil-filled eyes

Purpose

To investigate the effects of refractive accommodation on subfoveal choroidal thickness (SFCT) in silicone oil (SO)-filled eyes.

Methods

This retrospective, self-comparative study was conducted on 40 patients with unilateral macula-on rhegmatogenous retinal detachment, who underwent vitrectomy and SO tamponade. The SFCT of SO-filled eyes and the fellow control eyes were measured using optical coherence tomography at their one-month visit after surgery. The patients wore soft contact positive lenses for 24 h in the SO-filled eyes, to correct their refractive error. SFCT and choroidal vascularity index (CVI) were measured before and after wearing the contact lenses. Mean SFCT was compared between SO-filled eyes and the fellow control eyes, and SFCT and CVI were compared before and after refractive error correction in the SO-filled eyes.

Results

Mean SFCT of SO-filled eyes (221.52 ± 38.41 um) was less than that of the fellow eyes (273.41 ± 31.30 um) (P < 0.001). After refractive error correction, the mean SFCT increased to 269.28 ± 36.90 um(P < 0.001). However, CVI decreased from 57.01 ± 2.41 to 55.39 ± 2.39 (P < 0.05).

Conclusions

SFCT reduction in SO-filled eyes was primarily due to the hyperopia status. The non-uniform change in CVI suggests that changes in CT are mainly attributed to a greater expansion of the stromal area instead of the choroidal vascular area.

Trial registration

This study protocol was reviewed and approved by the Ethics Committee of the Central Theater General Hospital, approval number No. [2020]058–1, retrospectively registered.

Characteristics of Silicone Oil Emulsification After Vitrectomy for Rhegmatogenous Retinal Detachment: An Ultrasound Biomicroscopy Study

Purpose: To investigate the characteristics of silicone oil (SO) emulsification after vitrectomy for rhegmatogenous retinal detachment (RRD) and possible correlations with clinical factors. Methods: Patients who underwent primary pars plana vitrectomy with SO injection for RRD followed by SO removal at the Eye and ENT Hospital of Fudan University between January 2016 and January 2020 were included. Ultrasound biomicroscopy (UBM) images of the anterior segment were taken before SO removal. Eight signs of SO emulsification in the UBM images were graded as 1 (present) or 0 (not present) and the grades for all signs in each eye were summed. Correlations between SO emulsification grade and clinical factors were determined. Results: A total of 118 patients (118 eyes) were enrolled in this study. Emulsified SO particles were found in all 118 eyes (100%). The eight signs were more frequently detected in the superior part of the eye. The mean total SO emulsification grade was 19.99 ± 12.98 (range: 1-36). Younger age and male (both P < 0.05) were associated with higher total SO emulsification grade. Patients with intraocular pressure (IOP) > 21 mmHg or the use of antiglaucoma medications at the time of SO removal had a higher total SO emulsification grade, were younger, and were more frequently male (all P < 0.05) than patients without ocular hypertension. Conclusions: UBM could play an important role in the diagnosis and grading of SO emulsification. Younger patients and males are more prone to SO emulsification, which may lead to elevated IOP.

Adequate Silicone Oil Tamponade by Utilizing the Space of Anterior Segment for Complicated Retinal Detachment: Technique, Efficacy, and Safety

PURPOSE

To evaluate the efficacy and safety of adequate silicone oil (SO) tamponade procedure in patients with complicated retinal detachment.

METHODS

Thirty-one eyes in 31 patients were enrolled in this prospective case series. Adequate SO tamponade was performed by injecting the SO into the vitreous cavity and the entire anterior chamber, followed by posterior capsulotomy and inferior peripheral iridotomy. Preoperative and follow-up data including retinal anatomic reattachment and SO status, best-corrected visual acuity, intraocular pressure, surgical complications and management were collected and analyzed.

RESULTS

Twenty-nine eyes presented with complete retinal reattachment after subsequent SO removal with a primary success rate of 93.5%. Seventeen patients (54.8%) had complete anterior chamber SO migration to the vitreous cavity within the first postoperative day. The average time for anterior chamber SO migration was 2.3 ± 1.8 days. No oil-fluid interface in the vitreous cavity was observed in all the eyes, indicating a relatively adequate SO tamponade. Acute intraocular pressure elevation occurred in 16 (51.6%) eyes and was controllable under medication (n = 16) and anterior chamber paracentesis (n = 1). Two patients developed recurrent retinal detachment and received SO removal and a secondary adequate SO tamponade. At final follow-up, all the eyes had SO removal for at least 3 months and retinas maintained completely attached.

CONCLUSIONS

The adequate SO tamponade procedure offers a simple, safe, and efficacious treatment alternative for complicated retinal detachment.

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.

Combined Trabeculotomy-Trabeculectomy Versus Trabeculectomy for Treatment of Silicone Oil-induced Ocular Hypertension

PRCIS

Combined trabeculotomy-trabeculectomy (CTT) has a significantly better hypotensive effect than trabeculectomy and a higher success rate in cases of silicone oil-induced ocular hypertension.

PURPOSE

To compare the ocular hypotensive effect of CTT with mitomycin-C (MMC) to that of trabeculectomy with MMC in cases of silicone oil-induced ocular hypertension.

PATIENTS AND METHODS

Thirty eyes of 30 patients with high intraocular pressure (IOP) after vitrectomy and silicone oil injection (followed by silicone oil removal) were randomly allocated to 2 groups in this randomized trial. Group A was composed of 15 cases who underwent combined CTT with MMC while group B cases contained 15 cases undergoing trabeculectomy with MMC. Patients were followed up for 12 months. We included patients above 18 years old, having performed vitrectomy and silicone oil injection followed by oil removal, and having IOP >21 mm Hg uncontrollable by antiglaucoma medications.

RESULTS

The postoperative IOP drop was significantly greater in group A than in group B at all follow up visits (P<0.05). Compared with preoperative IOP, both surgeries produced a significantly lower postoperative IOP at all follow-up visits (P<0.05). For group A, complete success rates (IOP≤21 mm Hg without ocular hypotensive medications) and qualified success rates (IOP≤21 mm Hg with or without ocular hypotensive medications) were both higher than for group B.

CONCLUSION

Both surgeries effectively reduce IOP in cases of silicone oil-induced ocular hypertension, but CTT has a significantly better hypotensive effect and a higher success rate on the long-term.

Slow Coagulation Transscleral Cyclophotocoagulation for Postvitrectomy Patients With Silicone Oil-induced Glaucoma

PRECIS

Slow coagulation transscleral cyclophotocoagulation (TSCPC) is an effective and safe glaucoma surgery in patients with medically uncontrolled silicone oil (SO)-induced glaucoma.

PURPOSE

The purpose of this study was to report the outcomes of slow coagulation continuous wave TSCPC in patients with medically uncontrolled secondary glaucoma following pars plana vitrectomy (PPV) and intravitreal SO injection.

PATIENTS AND METHODS

This retrospective study enrolled patients with medically uncontrolled glaucoma secondary to PPV with SO injection who underwent TSCPC using slow coagulation TSCPC settings (power of 1250 mW and duration of 4 s). The primary outcome measure was surgical success at 12 months. Surgical success was defined as an intraocular pressure 6 to 21 mm Hg and reduced ≥20% from baseline, no reoperation for glaucoma, and no loss of light perception vision. Secondary outcome measures included number of glaucoma medications, visual acuity changes, and surgical complications.

RESULTS

A total of 18 eyes of 18 patients were included in the study. The mean age and follow-up of the patients were 51.94±14.5 years and 16.3±3.5 months, respectively. The mean intraocular pressure decreased from 29.7±9.6 mm Hg preoperatively to 14.6±6.5 mm Hg at 12 months postoperatively (P<0.001). Glaucoma medications were reduced from 4.2±0.9 at baseline to 1.9±1.3 at 12 months after TSCPC (P<0.001). A nonsignificant change of logarithm of the minimum angle of resolution visual acuity was observed at 12 months (P=0.722). The success rate at 12 months was 72.2%. No major complications were reported during the first year of follow-up.

CONCLUSION

Slow coagulation TSCPC had high efficacy and minimal complications when used as an initial glaucoma surgical procedure in patients with SO-induced glaucoma.

Trabeculectomy with OloGen versus Mitomycin C for the Treatment of Silicone Oil-Induced Glaucoma

AIM

To compare the intraocular pressure-lowering effect and success rate of trabeculectomy with OloGen to that of trabeculectomy with mitomycin C (MMC) in cases of silicone oil-induced glaucoma.

MATERIALS AND METHODS

Forty eyes of forty patients with elevated intraocular pressure (IOP) after vitrectomy and silicone oil injection (followed by silicone oil removal) were assigned to two groups. Group A included 20 cases who underwent trabeculectomy with OloGen, while group B cases contained 20 cases undergoing trabeculectomy with MMC. The follow-up period was 24 months. Patients enrolled had IOP > 21 mmHg despite being on antiglaucoma medications.

RESULTS

The mean postoperative IOP reduction was lower in group A than in group B at all follow-up visits, but this difference was not statistically significant (p > 0.05). Moreover, group A and B patients were found to be similar as regards the need for postoperative antiglaucoma medications on all follow-up visits. The Kaplan-Meier survival analysis curves for the two groups revealed slightly higher success rates in group B than in group A. However, these differences were not statistically significant for both qualified success (IOP ≤ 21 mmHg with or without antiglaucoma medications) and complete success (IOP ≤ 21 mmHg without antiglaucoma medications). There was no significant difference in the postoperative complication rate between the two groups.

CONCLUSION

OloGen implant lowers IOP to a similar extent as MMC when combined with trabeculectomy for the treatment of silicone oil-induced glaucoma, and with comparable success rates. The rate of postoperative complications is similar for OloGen implantation and MMC.

Silicone Oil Droplets in the Schlemm's Canal: A Surprise during Prolene Hemi-gonioscopy-assisted Transluminal Trabeculotomy (Hemi-GATT)

Aim and objective

To report a case with emulsified silicone oil (SO) droplets in the Schlemm's canal (SC), encountered during prolene hemi-gonioscopy-assisted transluminal trabeculotomy (hemi-GATT).

Background

In cases with a history of previous pars plana vitrectomy (PPV) with SO tamponade and then SO removal; glaucoma might occur secondary to the presence of emulsified SO droplets. Minimal invasive glaucoma surgeries targeting trabecular meshwork such as GATT surgery might be an ideal treatment option in these cases.

Case description

A 57-year-old man presented with uncontrolled intraocular pressure (IOP) and topical anti-glaucoma drug intolerance in his left eye. The patient had a history of PPV with SO tamponade and then intravitreal SO removal 5 years ago. He had a history of Ahmed glaucoma valve (AGV) implantation 2 years ago for the treatment of secondary glaucoma but he was still using topical anti-glaucoma medication. However, IOP was measured as 17 in the left eye. Hemi-gonioscopy-assisted transluminal trabeculotomy was performed successfully to get the patient off medication. During the surgery, SC was full of SO droplets.

Conclusion

The presence of SO droplets in the SC might contribute to the development of secondary glaucoma after PPV and SO removal. This might be another surgical indication for GATT surgery in these risky eyes.

How to cite this article

Aktas Z, Bölük CE, Gurelik G. Silicone Oil Droplets in the Schlemm's Canal: A Surprise during Prolene Hemi-gonioscopy-assisted Transluminal Trabeculotomy (Hemi-GATT). J Curr Glaucoma Pract 2021;15(1):40–43.

Intraocular pressure changes during and after silicone oil endotamponade (Review)

Silicone oil (SIO) has rapidly become an indispensable adjunct in vitreoretinal surgery. Constant improvements in purity and also in viscosity have not totally prevented specific complications that may occur during endotamponade. Results of in vitro studies that suggested that higher viscosity silicone oil might be superior in terms of stability and safety are confirmed in real life only if endotamponade lasts for more than 6 months. Intraocular pressure changes induced by the silicone oil endotamponade or oil extraction are documented from its very first use and are potentially threatening vision. The purpose of this review is to update current knowledge on the incidence, risk factors, pathogenesis, and management of secondary silicone oil glaucoma. Also, in a retrospective evaluation on cases with complex retinal detachments that underwent 23G vitrectomy and high viscosity SIO endotamponade, we have noticed that a considerable number of cases developed significant intraocular pressure changes during SIO endotamponade and after SIO removal, especially in early postoperative period.

Outcome of Surgical Management of Glaucoma Following Complex Retinal Detachment Repair With Silicone Oil Tamponade: Drainage Implant Versus Cyclophotocoagulation

PRéCIS:: Glaucoma drainage devices (GDDs) are effective for the management of silicone oil-induced glaucoma. Although cyclophotocoagulation (CPC) has the advantage of shorter operative time and repeatability, it carries a higher risk of failure, blindness, and phthisis.

BACKGROUND/AIMS

To compare the surgical outcome of GDD implantation and diode laser CPC in the management of refractory glaucoma following vitrectomy with silicone oil (SO) injection.

MATERIALS AND METHODS

In total, 56 eyes with refractory glaucoma after SO tamponade that underwent either CPC or GDD implantation were retrospectively evaluated. All patients underwent a complete ophthalmic examination and intraocular pressure (IOP) measurement at baseline and 1 day, 1 week, 1, 3, 6, and 12 months postoperatively. The rates of complete success and qualified success (for IOP between ≥5 and ≤21 mm Hg) were analyzed.

RESULTS

A total of 17 eyes underwent GDD implantation and 39 eyes underwent CPC. The preoperative IOP was 35.7±7.9 mm Hg and 27.8±8.4 mm Hg for the CPC and GDD groups, respectively (P=0.001), with a worse baseline visual acuity (P=0.01) and a higher proportion of SO-filled eyes in the CPC group (P<0.01). The IOP at 1 year postoperatively was 23.5±11.5 mm Hg and 15.3±5.9 mm Hg for the CPC and GDD group, respectively (P=0.01). Both groups achieved a reduction in IOP and number of medications at 1 year (P<0.001). The success rate in the GDD group was 94.1% (16/17), and 53.8% (21/39) in the CPC group at 12 months (P<0.005). Five eyes and 1 eye lost light perception vision in the CPC and GDD groups, respectively.

CONCLUSIONS

GDD implantation may carry a higher surgical success rate than CPC. However, CPC retains the advantage of being technically easier and repeatable.

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

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

The effect of silicone oil presence time on macular and choroidal thickness with macula-off rhegmatogenous retinal detachment

OBJECTIVE

To investigate the effects of silicone oil (SiO) on macular thickness (MT) and subfoveal choroidal thickness (SFCT) in patients with macula-off rhegmatogenous retinal detachment (RRD) undergoing pars plana vitrectomy (PPV).

MATERIAL AND METHODS

In this prospective study, 70 eyes of 70 patients who received SiO tamponade for the treatment of macula-off RRD were treated with PPV and a 5000-cSt SiO endotamponade followed by subsequent SiO removal. MT and SFCT were measured 1 day before and 3 months after SiO removal using spectral-domain optical tomography (SD-OCT) and enhanced depth imaging optical tomography (EDI-OCT). The patients were divided into 3 groups according to the length of time that the SiO was present: group 1 (3-6 months), group 2 (6-9 months), and group 3 (9-18 months).

RESULTS

A total of 70 eyes of 70 patients with a mean age of 57.22±9.83 years (range: 30 years to 75 years) were included in the SiO (5000-cSt) study. SiO was extracted after a mean duration of 8.67±5.33 months (range, 3-18 months) after PPV. In the 1st group, BCVA increased from 1.83±0.32 log MAR before PPV to 0.85±0.41 log MAR at 3 months after silicone removal (P<0.001). In the 2nd group, BCVA increased from 1.76±0.38 log MAR before PPV to 0.86±0.48 log MAR at 3 months after silicone removal (P<0.001). In the 3rd group, BCVA increased from 1.89±0.28 log MAR before PPV to 1.08±0.63 log MAR at 3 months after SiO removal (P=0.001). There was no statistically significant change in MT in the difference values of each group. As the length of SiO presence in the eye increased, significant thinning was observed on measurement of SFCT. Differences in the SFCT values were -14.91μm, -18.76μm, and -51.50μm in groups 1, 2, and 3 respectively (P=0.004).

CONCLUSIONS

A significant decrease in macular and choroidal thicknesses after SiO removal was observed. Presence of SiO endotamponade for 9 months was associated with subfoveal choroidal thinning and decreased final visual acuity in eyes undergoing RRD surgery. SD-OCT and EDI-OCT may be recommended for the treatment and follow-up of patients with complications caused by the use of SiO tamponade.

Foveal Microvascular Structures in Eyes with Silicone Oil Tamponade for Rhegmatogenous Retinal Detachment: A Swept-source Optical Coherence Tomography Angiography Study

Silicone oil (SO) is widely used as a long-term intravitreal tamponading agent for rhegmatogenous retinal detachment (RRD) repair. This study investigated the structural changes of the foveal microvasculature using optical coherence tomography angiography (OCTA) in patients with RRD treated with vitrectomy and SO tamponade. Thirty-eight patients with unilateral RRD who were treated with vitrectomy and SO tamponade and were followed up for ≥3 months after SO removal were included. En face OCTA images were obtained and foveal avascular zone (FAZ) area and vascular density (VD) were compared between study eyes and unaffected contralateral eyes. The FAZ area in deep capillary plexus (DCP) was larger (P < 0.001) and the VD in DCP was lower (P = 0.022) in the study eyes than in the fellow eyes. The duration of SO tamponade was significantly correlated with the enlargement of FAZ area (P = 0.034) and reduction of VD in DCP (P = 0.015). These changes could reflect vascular insufficiency in eyes with SO tamponade and may represent a potential explanation for the pathogenesis of retinal thinning and unexplained visual loss.

Incidence and outcomes of ocular hypertension from rhegmatogenous retinal detachment surgery in the acute postoperative setting

Purpose

To determine the incidence of ocular hypertension following surgery for rhegmatogenous retinal detachment in the first 3 months postoperatively and to determine their outcomes in terms of visual acuity, control of IOP, and changes in cup:disc ratio.

Patients and methods

A single center prospective cohort study was done involving patients who underwent retinal surgery for rhegmatogenous retinal detachment. The patients were followed up for 3 months postoperatively and were monitored for development of ocular hypertension. The primary outcome measures were changes in IOP, visual acuity, and cup:disc ratio.

Results

Of the 52 eyes enrolled in the study, 19 eyes developed ocular hypertension in the first 3 months postoperatively, giving an incidence rate of 36.5% (95% CI, 48.9-76.0%). Analysis of mean IOP trends shows that most cases of IOP elevations occur in the first day postoperatively with a sustained elevation up to the first month and then returning to normal levels by the 3rd month. There is a significant increase in mean cup:disc ratio among patients who developed ocular hypertension (p=0.047). Visual acuity trends show that mean visual acuity significantly improved from baseline among cases who maintained normal IOP (p=0.002) as compared to those who developed ocular hypertension (p=0.97), although the difference in final visual acuity at the end of 3 months between groups was not statistically significant (p=0.30).

Conclusion

Ocular hypertension may complicate retinal reattachment surgery. Control of IOP in the acute setting is essential to prevent development of secondary glaucoma.

The effect of multiple vitrectomies and its indications on intraocular pressure

Background

To assess the relationship between different indications for trans pars plana vitrectomies (PPV’s) and the intraocular pressure (IOP), and the effect of multiple PPV’s on the IOP. We also examined whether there were differences in the number of IOP-lowering medications or surgeries before and after PPV.

Methods

A retrospective study including all patients that underwent at least one PPV in the period from 2001 till 2014 at our clinic. Medical records of all patients were reviewed and clinically relevant data were entered in a database. Generalized estimating equations models for repeated measurements were used to examine the effect of the number of PPV’s on the IOP and on the risk of undergoing glaucoma surgery, for each of the indications for PPV.

Results

Of 1072 PPV’s 447 eyes fulfilled the inclusion criteria. The IOP increased with 3.0 mmHg after a PPV with indication retinal detachment (p < 0.001), but remained stable after PPV for epiretinal membrane (p = 0.555), macular hole (p = 0.695), and vitreous hemorrhage (p = 0.787). At the end of the follow-up period the number of IOP-lowering medications was significantly higher compared to baseline, except in the macular hole group (p = 0.103). Also, the number of eyes that underwent glaucoma surgery was significantly higher compared to the fellow (not-operated) eyes (p < 0.001). There was a significant association between the number of PPV’s and the final IOP for the indication retinal detachment (p = 0.009), and between the number of PPV’s and glaucoma surgery (odds ratio [95% confidence interval]: 2.60 [1.62–4.15]).

Conclusions

The IOP rises significantly after PPV with indication retinal detachment. This association was not found for other indications for PPV. Also, the risk of IOP-lowering surgeries was higher after PPV, but not different between the PPV indications. The IOP should be monitored carefully after PPV, since there may be a higher risk of secondary glaucoma.

Effects of Perfluorobutylpentane (F4H5) on Corneal Endothelial Cells

Purpose: To evaluate the effects of perfluorobutylpentane (F4H5) on corneal endothelial cell density (ECD) and morphology using a porcine corneal endothelial organ culture model. Materials and methods: "Split corneal buttons" were cultivated for 15 days (d) after incubation in F4H5 (15, 30, 60, and 120 min) or BSS (controls). ECD was assessed manually on d1, d8, and d15. After histological staining (trypan blue, alizarin red S) on d15 morphological changes (reformation figures, rosette formations, and alizarin red cells) were evaluated. Results: ECD was significantly reduced after incubation in F4H5 for 120 min (median ± 25%/75%-quartile; 3281 ± 43/222 cells/mm²; p = 0.046) on d15 compared to controls (3658 ± 129/296 cells/mm²), but not after shorter incubation times (15, 30, and 60 min). Morphological assessment supports these findings as reformation figures (F4H5 120 min: 10.5 ± 9.3/13.9/mm² vs. controls: 5.2 ± 2.8/7.2/mm²; p = 0.010), rosette formations (F4H5 120 min 25.566 ± 17.044/36.219/mm² vs. controls: 8.333 ± 0.000/15.667/mm²; p = 0.002), and alizarin red cells (F4H5 120 min: 38.350 ± 29.827/51.333/mm² vs. controls: 20.833 ± 10.417/25.000/mm²; p = 0.049) were significantly more prevalent after incubation in F4H5 for 120 min compared to controls. Also, F4H5 60 min showed significantly more rosette formations (25.452 ± 16.968/36.057/mm²; p = 0.006) and alizarin red cells (46.662 ± 42.420/50.903/mm²; p = 0.007), but not reformation figures (7.0 ± 2.2/1.6 %; p = 0.953). Conclusion: Short exposure (≤30 min) of porcine corneal endothelial cells to F4H5 does not have significant effects on ECD or morphological characteristics. Longer exposure times (≥60-120 min) may cause ECD decline and/or induce morphological changes.

Estimating three-dimensional outflow and pressure gradients within the human eye

In this paper we set the previously reported pressure-dependent, ordinary differential equation outflow model by Smith and Gardiner for the human eye, into a new three-dimensional (3D) porous media outflow model of the eye, and calibrate model parameters using data reported in the literature. Assuming normal outflow through anterior pathways, we test the ability of 3D flow model to predict the pressure elevation with a silicone oil tamponade. Then assuming outflow across the retinal pigment epithelium is normal, we test the ability of the 3D model to predict the pressure elevation in Schwartz-Matsuo syndrome. For the first time we find the flow model can successfully model both conditions, which helps to build confidence in the validity and accuracy of the 3D pressure-dependent outflow model proposed here. We employ this flow model to estimate the translaminar pressure gradient within the optic nerve head of a normal eye in both the upright and supine postures, and during the day and at night. Based on a ratio of estimated and measured pressure gradients, we define a factor of safety against acute interruption of axonal transport at the laminar cribrosa. Using a completely independent method, based on the behaviour of dynein molecular motors, we compute the factor of safety against stalling the dynein molecule motors, and so compromising retrograde axonal transport. We show these two independent methods for estimating factors of safety agree reasonably well and appear to be consistent. Taken together, the new 3D pressure-dependent outflow model proves itself to capable of providing a useful modeling platform for analyzing eye behaviour in a variety of physiological and clinically useful contexts, including IOP elevation in Schwartz-Matsuo syndrome and with silicone oil tamponade, and potentially for risk assessment for optic glaucomatous neuropathy.

Biological Characteristics of Subsilicone Oil Fluid and Differences With Other Ocular Humors

Purpose

Subsilicone oil fluid (SOF) in eyes with silicone oil (SO) endotamponade possibly has a role in complications (e.g., vision loss); thus, we aimed to examine inflammatory cytokine and electrolyte levels and retinal glial cell viability in SOF.

Methods

We measured major inflammatory cytokine levels and electrolytes in SOF and compared them with those in vitreous fluid (VF) and anterior chamber fluid (ACF). We analyzed the correlation between inflammatory cytokines and retinal thickness in SO-filled eyes. Further, we measured the MIO-M1 cell viability in medium with SOF and compared it with that containing VF.

Results

We collected and examined 57 SOF, 22 ACF, and 21 VF samples from eyes with PVR, PDR, RD, and MH. Interleukin (IL)-8 and monocyte chemoattractant protein (MCP)-1 levels in SOF were significantly higher than those in ACF. There was no significant difference for all cytokines between SOF and VF. Retinal thickness changes during SO endotamponade were not correlated with the presence of any inflammatory cytokines. Levels of ferrous iron, but not of potassium, showed a significant decrease in SOF compared with VF. The WST-1 assay showed that SOF-added medium induced higher MIO-M1 cell viability than VF-added medium.

Conclusions

We found no significant correlation between the change in the retinal thickness and cytokine levels, but SOF contains higher concentrations of cytokines and lower concentrations of ferrous iron and can be biologically distinguished from ACF and VF.

Translational Relevance

Novel knowledge of inflammatory cytokine levels and electrolytes in SOF provides better understanding of pathology of SO-filled eyes.

Influence of Vitrectomy-related Factors on the Outcome of Ahmed Glaucoma Valve Implantation

Purpose

To evaluate the outcome of Ahmed glaucoma valve (AGV) implantation in eyes with refractory secondary glaucoma following pars plana vitrectomy (PPV) and the associated prognostic factors.

Methods

A total of 146 eyes in 146 patients who underwent AGV implantation after PPV (followed up for ≥1 year) were included. AGV implantation was considered successful when the intraocular pressure (IOP) was 6 to 21 mmHg regardless of using IOP-lowering medication. The hazard ratios (HRs) associated with surgical failure were determined with Cox proportional analysis.

Results

The most common cause for PPV was complications of proliferative diabetic retinopathy (50%). The mean and peak IOPs between PPV and AGV implantation were 26.9 ± 6.6 and 35.9 ± 10.2 mmHg, respectively. AGV implantation was performed on average 18.7 months after PPV, and its overall success rate was 80.1% during a mean follow-up period of 43.6 months. In multivariate analyses, rubeosis observed before AGV implantation (HR, 4.07; 95% confidence interval, 1.57 to 10.6; p = 0.004) and higher peak IOP before AGV (HR, 1.04; 95% confidence interval, 1.00 to 1.07; p = 0.034) were predictive of failure. However, no PPV-related factors were associated with the surgical outcome of AGV implantation.

Conclusions

The outcome of AGV implantation is good in refractory glaucoma following PPV. Rubeosis after PPV and higher peak IOP before AGV are risk factors for poor outcomes. Patients who undergo PPV should be followed for the development of rubeosis and IOP control.

Positional Intraocular Pressure of Vitrectomized and Normal Fellow Eyes

Purpose

To compare posture-induced intraocular pressure (IOP) changes in vitrectomized eyes and normal eyes of patients who had vitrectomy in one eye.

Methods

A total of 31 patients older than 20 years of age who underwent vitrectomy were enrolled in the study. At least six months after vitrectomy, we measured IOP in both eyes using a rebound tonometer 10 minutes after the patient assumed sitting, supine, right lateral decubitus, and left lateral decubitus positions. Patients with a history of ocular surgery (not including vitrectomy) or recent medication use associated with IOP were excluded. IOP and ocular parameters of vitrectomized and normal fellow eyes were compared. For the decubitus position, IOP values of dependent and nondependent eyes were compared.

Results

No significant difference was observed in IOP between vitrectomized and normal eyes in the sitting and supine positions. The IOP for dependent eyes (on the lower side in the lateral decubitus position) was significantly higher than the IOP for nondependent eyes in both right lateral decubitus (right vitrectomized eye 19.31 ± 4.20 vs. 16.71 ± 4.02 mmHg, p < 0.001; left vitrectomized eye 18.35 ± 1.75 vs. 16.04 ± 3.02 mmHg, p = 0.003) and left lateral decubitus (right vitrectomized eye 17.32 ± 4.63 vs. 19.15 ± 3.83 mmHg, p = 0.004; left vitrectomized eye 16.19 ± 1.81 vs. 18.12 ± 2.29 mmHg, p < 0.001) positions.

Conclusions

IOP was higher in the dependent than the nondependent eye in the lateral decubitus position, for both vitrectomized and nonoperated eyes.

Lasers in glaucoma

While lasers have been used for many years for the treatment of glaucoma, proper indications and use of the procedures need to be considered before their application. This review summarizes the important laser procedures in Glaucoma.

Clinicopathological features of epiretinal membranes in eyes filled with silicone oil

Purpose

The aim of this case series was to clarify the clinicopathological features of epiretinal membranes (ERMs) that developed in eyes after silicone oil (SO) tamponade to treat rhegmatog-enous retinal detachments (RRDs).

Patients and methods

In the Department of Ophthalmology, Saitama Medical Center, Jichi Medical University, patients with idiopathic ERMs (23 eyes) and ERMs in eyes filled with SO (SO ERMs) after vitreous surgery to treat RRDs (nine eyes) were enrolled from July 2012 to March 2014. ERM tissues obtained intraoperatively were examined histopathologically. Besides the main outcome measure of the pathological findings of the ERM tissues, other outcome measures included the preoperative findings on optical coherence tomography (OCT) images and the surgical findings.

Results

Eight (89%) of nine eyes with SO ERMs had bilayered membranes composed of a firm layer on the retinal side with glial cells and extracellular matrix and a fragile sponge-like layer on the vitreous side. The sponge-like layer was composed of emulsified SO surrounded by macrophages. Quantitative analysis showed that the areas with cluster of differentiation 68 (CD68)-positive macrophages identified by immunohistochemistry in eyes with SO ERMs were significantly (P<0.001) larger than those in eyes with idiopathic ERMs. The findings on OCT images were consistent with the pathological features of the SO ERMs. Surgical removal of the SO ERMs was difficult because the sponge-like layer was fragile, and the underlying retina was also fragile due to inflammation.

Conclusion

SO ERMs are bilayered membranes. Long-standing emulsified SO formed a sponge-like layer and SO (foreign body)-induced granulation and caused retinal inflammation in these eyes, making surgical removal difficult. A preoperative OCT examination is necessary to identify SO ERMs.

Retina and glaucoma: surgical complications

Background

The close structural and microcirculatory co-relation between anterior and posterior segments of eye make them very vulnerable to complications when one of them is affected surgically. With the advent of anti-fibrotic agents in the management of glaucoma, the rates of vitreoretinal complications have become more frequent.

Main body

Common retinal complications after glaucoma surgeries include choroidal detachment; ocular decompression retinopathy; haemorrhagic choroidal detachment; hypotony maculopathy; malignant glaucoma; vitreous haemorrhage; bleb endophthalmitis; retinal detachment. Similarly, intraocular pressure rise is often noted after scleral buckle; pars plana vitrectomy; intravitreal gas injection; silicone oil injection; intravitreal steroid injection.

Conclusion

The article provides some insight into some of the complications after glaucoma and retina surgeries, including the pathogenetic mechanisms behind each complication and available management options.

Single-pass four-throw pupilloplasty for secondary angle-closure glaucoma associated with silicon oil tamponade

PURPOSE

To describe the feasibility and efficacy of performing single-pass four-throw pupilloplasty for secondary angle-closure glaucoma post silicon oil tamponade.

METHODS

The procedure was performed in five eyes of five patients. All the cases underwent silicon oil removal with single-pass four-throw pupilloplasty. Single-pass four-throw procedure involves a single pass of needle through the iris tissue that is to be apposed followed by taking four throws by passing the suture end through the loop that is withdrawn from the anterior chamber as in a modified Siepser's slip-knot technique. Both the suture ends are pulled and this leads to sliding of the loop into the anterior chamber. Surgical pupilloplasty stretches the peripheral iris tissue and helps in breaking the peripheral anterior synechia. Intraoperative gonioscopy and anterior segment optical coherence tomography were performed in all the cases.

RESULTS

Intraoperative gonioscopy and anterior segment optical coherence tomography demonstrated opening of the anterior chamber angles with breakage of peripheral anterior synechia. The mean preoperative and postoperative best-corrected visual acuity in logarithm of minimum angle of resolution was 1.24 ± 0.23 and 0.56 ± 0.18, respectively (p < 0.001). The mean preoperative and postoperative intraocular pressure was 38.2 ± 4.97 and 13.0 ± 2.35 mm Hg, respectively. There was a significant decrease in intraocular pressure and marked improvement in visual acuity in all the cases.

CONCLUSION

Surgical pupilloplasty helps to relieve the post-silicon oil-induced secondary angle-closure glaucoma by breaking peripheral anterior synechia and significantly opening the anterior chamber angles.

Modulated release from implantable ocular silicone oil tamponade drug reservoirs

Complicated cases of retinal detachment can be treated with silicone oil tamponades. There is the potential for silicone oil tamponades to have adjunctive drug releasing behaviour within the eye, however the lipophilic nature of silicone oil limits the number of drugs that are suitable, and drug release from the hydrophobic reservoir is uncontrolled. Here, a radiometric technique was developed to accurately measure drug solubility in silicone oil and measure release into culture media. All-trans retinoic acid (atRA), a lipophilic drug known to act as an anti-proliferative within the eye, was used throughout this work. Chain-end modification of polydimethylsiloxane with atRA produced a polydimethylsiloxane retinoate (PDMS-atRA), which was used as an additive to silicone oil to modify the solvent environment within the silicone oil and the distribution coefficient. Blends of PDMS-atRA and silicone oil containing different concentrations of free atRA were produced. The presence of PDMS-atRA in silicone oil had a positive effect on atRA solubility and the longevity of release in vitro. The drug release period was independent of atRA starting concentration and dependent on the PDMS-atRA concentration in the blend. A clinically relevant release period of atRA over 7 weeks from a silicone oil blend with PDMS-atRA was observed. © 2018 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 938-946.

DIFFERENT SURGICAL MODALITIES FOR MANAGEMENT OF PERSISTENT GLAUCOMA AFTER SILICONE OIL REMOVAL IN VITRECTOMIZED EYES: One Year Comparative Study

PURPOSE

Aim of this study was to compare outcome of four different surgical modalities for management of persistent glaucoma after silicone oil removal in vitrectomized eyes.

METHODS

This is a prospective comparative study, carried out on a cohort of 41 eyes (41 patients). Patients were randomly allocated to Group A (trabeculectomy), Group B (deep sclerectomy), Group C (Ahmed valve), or Group D (Ex-Press Minishunt). Postoperatively, all patients were followed regularly at 1 day, 1 week, 1, 3, and 6 months, and 1 year for intraocular pressure evaluation.

RESULTS

Postoperatively, there was significant drop in intraocular pressure in each group, and significant difference between the four groups regarding drop and percentage drop in intraocular pressure, with Group C showing the highest mean percentage drop in intraocular pressure, whereas Group B with the least. Success rate was 100% with Ex-Press minishunt, 80% with Ahmed valve, and 50% for each of trabeculectomy and deep sclerectomy. Hypotony occurred in 50% with Ahmed valve and 40% with trabeculectomy, whereas glaucoma occurred in 50% with deep sclerectomy and 30% with trabeculectomy.

CONCLUSION

For controlling persistent glaucoma after silicone oil removal in our work, Ex-Press minishunt had the highest complete success rate with no postoperative complications.

Intraocular pressure 1 year after vitrectomy in eyes without a history of glaucoma or ocular hypertension

Objective

The aim of this study was to investigate the incidence, risk factors, and treatment of elevated intraocular pressure (IOP) 1 year after vitrectomy in eyes without a history of glaucoma or ocular hypertension.

Patients and methods

This retrospective study comprised 256 eyes from 256 consecutive patients without a history of glaucoma or ocular hypertension who underwent vitrectomy and were followed up for 1 year. The incidence of elevated IOP at 1 year after vitrectomy was calculated. We compared the characteristics of patients with or without elevated IOP to identify possible risk factors for elevated IOP. The treatments used to control IOP were recorded and analyzed.

Results

A total of 50 patients (19.5%) had elevated IOP after vitrectomy at the 1-year follow-up. Tamponade was a significant risk factor for elevated IOP (P<0.05). The cumulative rates of elevated IOP in eyes with air, balanced salt solution, sulfur hexafluoride, perfluoropropane (C3F8), and silicone oil as the tamponade were 0, 10.8%, 5.9%, 19.8%, and 28.4%, respectively (P<0.05). About 68% of cases of elevated IOP occurred within 1 month after vitrectomy. At 1 year after vitrectomy, 29 patients (58.0%) had stopped their IOP-lowering drugs and 21 (42.0%) patients were continuing these drugs. About 65% of ocular hypertension patients who received silicone oil tamponade had not stopped IOP-lowering drugs; this rate was significantly greater than that of ocular hypertension patients who received C3F8 tamponade (18.2%, P<0.05).

Conclusion

Elevated IOP is a common complication after vitrectomy. Silicone oil tamponade was associated with greater risk of elevated IOP and had long-term effects on IOP. Drugs and surgery were used to control IOP, and some patients required long-term IOP-lowering therapy.