INCIDENCE, RISK FACTORS, AND CLINICAL CHARACTERISTICS OF UNEXPLAINED VISUAL LOSS AFTER INTRAOCULAR SILICONE OIL FOR MACULA-ON RETINAL DETACHMENT

Retinal vascular changes after Silicon Oil removal in the Eye with Rhegmatogenous Retinal detachment

BACKGROUND

This study aims to examine vessel density changes in the optic nerve and macula following silicone oil removal (SOR) surgery in eyes with rhegmatogenous retinal detachment (RRD) at different time points by Optical Coherence Tomography Angiography (OCTA) in compared to the contralateral eye.

METHODS

A total of 43 eyes from 43 patients with silicone oil in their eyes for 3-9 months underwent OCT-A using AngioVue and optic disc-associated vessel density (VD) and thickness, macular-associated VD and thickness, Foveal avascular zone (FAZ) area, FAZ perimeter (PERIM), Acircularity index (AI), vessel density within a 300 μm wide region of the FAZ were compared between eyes. OCTA scans were performed one week before SOR and one month and three months after SOR.

RESULTS

The mean age of participants was 52.8 years (SD = 15.85) and a median visual acuity was 0.8 (range: 0.5-1.0). Notably, male participants constituted 67.4% of the sample. The preoperative mean value BCVA (logMAR) of patients was 0.73, and 3 months post-oil removal was 0.7727. Regarding optic disc parameters, RNFL thickness and vessel density (VD) measurements Peripapillary, whole disc, inside disc, and Disc Angio (superior, Nasal, inferior, temporal) did not change. In analyzing macular thickness parameters, all of them (Whole and Fovea, parafoveal, and Perifovea) remained unchanged. Examining macular vessel density parameters revealed no significant changes across superficial and deep retinal layers. Finally, the comparison of the foveal avascular zone (FAZ) area and flow density (FD) parameters demonstrated consistent measurements with non-significant alterations observed in FAZ size (p = 0.6) and FD values (p = 0.49) over the monitored duration.

CONCLUSION

There was no change in peripapillary VD and macular vessel density of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) after silicone oil removal. FAZ and full retinal thickness  remained stable 3 month after SOR.  Clinical trial number: Not applicable.

Retinal Toxicity Assessment Following Vitreoretinal Surgery: A Comparison of Silicone Oil and Perfluoropropane Tamponade Using Diopsys® NOVA™

PURPOSE

This study aimed to assess and compare the retinal toxicity associated with silicone oil (SO) and perfluoropropane (C3F8) tamponade following vitreoretinal surgery for fresh rhegmatogenous retinal detachment (RRD), utilizing the office-based Diopsys® NOVA™ system for evaluation.

METHODS

Patients who underwent vitreoretinal surgery for fresh RRD and had SO (group 1) or C3F8 (group 2) tamponade were included in a prospective analysis. Flicker full field electroretinography (ffERG) and pattern electroretinography (PERG) tests were performed at 6 months postoperatively.

RESULTS

Postoperative best corrected visual acuity (logMAR) was significantly different in group 1 and group 2 patients, 0.48 ± 0.3 and 0.30 ± 0.2, respectively. No significant disparities were found in demographic variables. Flicker ffERG and PERG recordings revealed notable alterations in retinal function parameters in the group 1 compared to the group 2.

CONCLUSION

Our findings suggest a correlation between SO tamponade and retinal dysfunction, evidenced by office-based ERG measurements. The Diopsys® NOVA™ protocol offers clinical ease in assessing retinal function. Further controlled studies are essential to validate these findings and guide clinical practice effectively.

Three-Dimensional Quantitative Analysis of Internal Limiting Membrane Peeling Related Structural Changes in Retinal Detachment Repair

PURPOSE

To assess macular microstructural changes associated with internal limiting membrane peeling (ILMP) using 3-dimensional optical coherence tomography (3D-OCT) in primary macula-off rhegmatogenous retinal detachment (RRD) repairs with vitrectomy and silicone oil (SO) tamponade.

DESIGN

Retrospective, consecutive, interventional case series.

METHODS

Setting: Institutional practice.

PATIENT POPULATION

Patients who received primary RRD repair by a single experienced surgeon between January 2017 and December 2021.

MAIN OUTCOME MEASURES

In the qualitative comparative analysis, the presence of macular changes among patients who underwent primary RRD repair with (21 eyes) or without ILMP (20 eyes) were observed. Subsequently, a detailed quantitative analysis of ILMP-related microstructural changes in 56 eyes using both 3D and 2D-OCT images were performed.

RESULTS

In the qualitative comparative analysis, macular microstructural changes were observed in 95% of ILMP eyes and 5% of non-ILMP eyes (p < .001). In the quantitative analysis, 4 major macular microstructural changes were detected: dimple (75%), dissociated nerve fiber layer (DONFL) (55%), ILM peeling edge thinning (IPET) (64%), and temporal macular groove (TMG) (23%). Dimples (n = 251, average 4.5 ± 5.8 per eye) could be further classified into type I (confined to the inner plexiform layer [IPL]; 73%) and type II (beyond IPL, 27%). The average depth of the deepest dimples was 58 ± 18 µm. The extent of IPET was 6.0 ± 3.7 clock hours. The average length of TMG was 1.8 ± 0.4 mm. Comparing to unoperated fellow eyes, the eyes after ILMP showed decreased inner temporal over nasal retinal thickness ratio (0.86 ± 0.07 versus 0.96 ± 0.03, p < .001), shorter disc-fovea distance (4.61 ± 0.32 µm versus 4.78 ± 0.37 µm, p = .041), and wider retinal vein trajectories (c' = 2.48 ± 0.84 vs 3.39 ± 1.61, p = .002).

CONCLUSIONS

Macular microstructural changes are common after ILMP in RRD repair, encompassing both focal changes (dimples, DONFL) and zonal changes (IPET, TMG). DONFL and dimples may be part of a continuum of findings stemming from the same mechanism. IPET and TMG are the results of macular tissue shift due to contracture of the optic disc and neurovascular bundle.

Management of macula-on giant retinal tear detachments- outcome of pars-plana-vitrectomy with silicone oil versus gas tamponade

BACKGROUND

To compare the outcome of eyes with a macula-on giant retinal tear (GRT) detachment treated with pars-plana-vitrectomy (PPV) depending on the used endotamponade.

METHODS

All consecutive cases with a macula-on GRT-associated rhegmatogenous retinal detachment (RRD) managed with PPV between 2007 and 2022 were retrospectively assessed depending on the selected endotamponade. By reviewing medical charts and surgical protocols the pre- and intraoperative parameters were analysed in detail. The number of vitreoretinal (VR) procedures needed for reattachment, the redetachment rate and the functional outcome were evaluated. Eyes treated with primary silicone oil (SO) tamponade were compared to eyes with primary gas tamponade. Cases with pre-existing conditions affecting outcome e.g. macula-off situation, history of trauma, status after complicated cataract surgery, former VR surgery or proliferative vitreoretinopathy grade C or higher were excluded.

RESULTS

Overall, 51 eyes of 45 patients with a macula-on GRT detachment were treated with PPV and SO (n = 32; 63%) or gas (n = 19; 37%) endotamponade in the observed period. Eyes with primary SO tamponade underwent on average 2.3 (SD 0.8) VR procedures and had a redetachment rate of 13% (n = 4). Eyes with gas tamponade showed a higher redetachment rate of 32% (n = 6) with a mean number of 1.6 (SD 1.0) PPV procedures. Postoperative best-corrected visual acuity (BCVA) was significantly better in eyes with primary gas tamponade (mean logMAR BCVA 0.32; SD 0.30) compared to eyes with SO (mean logMAR BCVA 0.60; SD 0.42; p = 0.008).

CONCLUSIONS

Surgical management of GRT-associated RRDs is complex. In clinical routine often SO is used as endotamponade. Because of known disadvantages (second procedure necessary for SO removal, unexplained SO-related visual loss, secondary glaucoma, SO emulsification) some VR surgeons prefer a gas tamponade. In our cohort, eyes with a gas compared to SO tamponade showed higher redetachment rates. However, the final postoperative BCVA was significantly better in eyes with gas compared to SO tamponade.

TRIAL REGISTRATION

The trial protocol was approved by the local ethics committee on 25th of November 2022 (Ethikkommission der Universität Regensburg, Votum 22-3166-104).

Contamination Profile of Different Formulations of Silicone Oil Tamponade Before and After Intraocular Permanence for Rhegmatogenous Retinal Detachment

Purpose

The purpose of this study was to search for contaminants in silicone oil tamponades removed from eyes treated for retinal detachment, and to correlate chemical results with some clinical/functional parameters of the considered eyes.

Methods

We examined a sequential cohort of eyes grouped according to the tamponade received: (1) Siluron2000 (S2), (2) RS-OIL ECS5000 (S5), and (3) Densiron Xtra (DX). Samples were collected at the beginning of the scheduled removal and analyzed by untargeted headspace gas-chromatography mass spectrometry (HS-GC-MS). Visual acuity and optic coherence tomography assessments were obtained before and after the tamponade removal.

Results

Forty-one samples were analyzed: 22 belonging to the DX group, 13 to the S2 group, and 6 to the S5 group. For each group, a mixture of uninjected commercial preparation was analyzed as the reference. Different siloxanes and fluorinated compounds including perfluorodecalin (PFCL) were the most prevalent chemicals, found in 55% to 100% of the intraocular samples of the 3 groups. Some siloxanes were present also in the control matrices, whereas PFCL was only in the extracted tamponades. In the DX group, the concentration of hexamethylcyclotrisiloxane showed an inverse correlation trend with the duration of its permanence inside the eye (P = 0.054). Different alkanes, propanol, and acetaldehyde were identified only in the control matrices.

Conclusions

Several contaminants including siloxanes were identified in the intraocular samples and in the control matrices. A time-related ocular uptake of some of these is conceivable. PFCL was also highly present but only in intraocular samples.

Translational Relevance

After intraocular permanence silicone oils (SOs) have various unlabeled contaminants with some relevant differences with the commercial formulation chemical profile.

Evaluation of retinal structural and functional changes after silicone oil removal in patients with rhegmatogenous retinal detachment: a retrospective study

BACKGROUND

To evaluate retinal structural and functional changes after silicone oil (SO) removal in eyes with macula-off rhegmatogenous retinal detachment (RRD).

METHODS

Best-corrected visual acuity (BCVA) testing, microperimetry, and optical coherence tomography angiography were performed in 48 eyes with macula-off RRD before and 3 months after SO removal. The values of healthy contralateral eyes were used as control data. Correlations between retinal vessel density (VD), retinal nerve fiber layer thickness (RNFLT), the interval between retinal detachment and surgery, the duration of SO tamponade, the follow-up time after SO removal, and visual function were analyzed.

RESULTS

Significant increases in 2˚ fixation rate (FR), 4˚ FR, 2˚ mean retinal sensitivity (MRS), 6˚ MRS, parafoveal superficial capillary plexus VD and RNFLT were observed after SO removal (all P < 0.05). The increase of 2˚ MRS and 6˚ MRS were correlated with the duration of SO tamponade and the follow-up time after SO removal respectively (all P < 0.05). The last 2˚ MRS and 6˚ MRS were correlated with the duration of SO tamponade, the interval between retinal detachment and surgery, and the follow-up time after SO removal (all P < 0.01). The last FR in RRD eyes was close to that of contralateral eyes (P > 0.05).

CONCLUSION

Retinal structure and function improved to different degrees after SO removal. Fixation stability and retinal sensitivity increased more than BCVA postoperatively. Retinal sensitivity, which was affected by the interval between retinal detachment and surgery and the duration of SO tamponade, gradually recovered after SO removal.

Choroidal vascular changes in silicone oil-filled eyes after vitrectomy for rhegmatogenous retinal detachments

INTRODUCTION

The tamponade of silicone oil (SO) can affect both the structure and blood flow of the retina. However, there are few studies on the effect of SO tamponade on choroidal blood flow. Our study aimed to compare the effects of SO tamponade on the choroidal vascular index (CVI) and choroidal thickness (CT) in patients with unilateral rhegmatogenous retinal detachment (RRD) with operated eyes and fellow healthy eyes.

METHODS

We retrospectively collected demographic and clinical data from 36 patients who underwent 23G pars plana vitrectomy and SO tamponade for unilateral complicated RRD. Enhanced depth imaging-optical coherence tomography (EDI-OCT) scans were performed both within 1 week before SO removal and at the last follow-up visit after SO removal. Using ImageJ software, images were binarized to segment the total choroidal area, luminal area, and stromal area, respectively. The CVI was calculated as CVI=(luminal area)/(total choroidal area), and CT was also evaluated.

RESULTS

During SO tamponade, the CVI and luminal area in operated eyes were significantly lower compared to fellow eyes (57.616 ± 0.030 vs. 60.042 ± 0.019, P < 0.0001; 0.909 [0.694; 1.185] vs. 1.091 [0.785; 1.296], P = 0.007). Even after SO removal, the CVI remained lower in operated eyes than in fellow eyes (59.530 ± 0.018 vs. 60.319 ± 0.020, P = 0.031). Both CVI and luminal area were lower in operated eyes before SO removal than after SO removal (57.616 ± 0.030 vs. 59.530 ± 0.018, P = 0.0003; 0.909 [0.694; 1.185] vs. 0.994 [0.712; 1.348], P = 0.028). The duration of SO tamponade was positively correlated with the difference in CVI between fellow eyes and operated eyes during SO tamponade (P = 0.035). Total choroidal area, stromal area, and CT did not differ significantly between fellow eyes and operated eyes or between pre- and post-SO removal.

CONCLUSIONS

SO tamponade reduces CVI and decreases choroidal blood circulation in patients with retinal detachments required vitrectomy combined with SO tamponade. The longer the SO tamponade time, the more CVI reduction. In future work, we will aim to reduce these side effects by shortening the duration of silicone oil filling.

Clinical Outcome of Cystoid Macular Edema in Silicone Oil-Filled Eyes

Purpose: To investigate the clinical outcome of cystoid macular edema (CME) in eyes undergoing silicone oil (SO) tamponade with subsequent SO removal (SOR). Methods: A retrospective case series of adult patients with CME treated with SO tamponade and SOR was conducted between January 2015 and January 2021. Exclusion criteria included eyes with a prior SO tamponade, those that did not undergo SOR, or those with infectious/inflammatory diagnoses. The primary outcomes were the incidence and resolution rates of CME in eyes with SO tamponade that had undergone SOR. The secondary outcomes included changes in best-corrected visual acuity (BCVA) and central field thickness (CFT). Results: Nineteen eyes of 19 patients (58% men) aged 52 years (interquartile range [IQR], 45-66 years) met the study inclusion criteria. The median (IQR) follow-up duration post SOR was 22 (8-35) months. The mean CFT decline for the CME-resolved cases was 13.1 µm/mo (P = .257). CME resolved in only 10 eyes (53%), 7 (67%) of which occurred after SOR. The median (IQR) BCVA was 20/400 (20/200 to 20/1262) at CME diagnosis and 20/796 (20/252 to hand motions) after SOR, with 0.184 worsening in logMAR BCVA (P = .340). Medical treatment was not associated with CME resolution compared with observation (50% vs 89%, respectively; P = .069). Eyes with proliferative vitreoretinopathy (PVR) had a higher rate of persistent CME compared with eyes with other diagnoses (78% vs 10%, respectively; P = .005). Conclusions: Nearly half had nonresolution of CME after SO was removed. The VA at the last follow-up was unaffected by CME resolution. Preoperative PVR may be a risk factor for unresolved CME.

Clinical utilization of microperimetry in ophthalmic surgery: A narrative review

Microperimetry is an emerging technology that provides concurrent analysis of retinal structure and function by combining retinal sensitivity and fixation analysis with fundus imaging. We summarize the substantial evidence validating the evolving role of microperimetry as an adjunctive assessment of visual function in the perioperative setting. We show that microperimetry provides useful complementary information to other established imaging and functional modalities in the perioperative setting for a wide range of vitreoretinal surgical procedures, as well as in cataract and refractive surgeries. This includes preoperative uses such as prognostication of visual and anatomical outcomes, timing of surgical intervention, and assessment of patient suitability for surgery-as well as postoperative uses including quantification of visual recovery, investigation of unexplained postoperative vision loss, and informing expected long term functional outcomes.

Unexplained Vision Loss Associated With Intraocular Silicone Oil Tamponade in Rhegmatogenous Retinal Detachment Repair

Purpose: To evaluate the visual outcomes with unexplained vision loss during or after silicone oil (SO) tamponade. Methods: This multicenter retrospective case series comprised patients with unexplained vision loss associated with SO tamponade or its removal. Eyes with other clear secondary identifiable causes of vision loss were excluded. Results: Twenty-nine eyes of 28 patients (64% male) were identified. The mean age was 50 ± 13 years (range, 13-78 years). The mean duration of SO tamponade was 148 ± 38 days. Eighteen eyes (62%) developed unexplained vision loss while under SO; 11 (38%) had vision loss after SO removal. The most common optical coherence tomography (OCT) finding was ganglion cell layer (GCL) thinning (55%). Eyes with vision loss after SO removal had a mean logMAR best-corrected visual acuity (BCVA) of 0.6 ± 0.7 (Snellen 20/85) before SO tamponade and 1.2 ± 0.4 (20/340) before SO removal. By the last follow-up after SO removal, the BCVA had improved to 1.1 ± 0.4 (20/235). In eyes with vision loss after SO removal, the BCVA before SO removal was 0.7 ± 0.7 (20/104), which deteriorated to 1.4 ± 0.4 (20/458) 1 month after SO removal. By the last follow-up, the BCVA had improved to 1.0 ± 0.5 (20/219). Conclusions: Unexplained vision loss can occur during SO tamponade or after SO removal. Vision loss was associated with 1000-centistoke and 5000-centistoke oil and occurred in macula-off and macula-on retinal detachments. The duration of tamponade was 3 months or longer in the majority of eyes. Most eyes had GCL thinning on OCT. Gradual visual recovery can occur yet is often incomplete.

The Emulsification of Silicone Oil 5000 cs in Patients With Retinal Detachment

Background The emulsification of silicone oil is a significant concern for those with rhegmatogenous retinal detachment (RRD) following surgery. The aim of the study was to assess the frequency of emulsification in the patients who underwent primary vitrectomy and were administered 5000 cs silicone oil. Methodology The Layton Rahmatullah Benevolent Trust in Lahore conducted an ophthalmology study from January 2022 to March 2023. The patients who had primary vitrectomy for RRD with silicone oil tamponade were included regardless of age or gender. Those on anti-inflammatory or steroid medications prior to surgery were excluded. Retinal attachment was examined 8-12 weeks post operation to assess silicone oil removal eligibility. Emulsification occurrence was reported. Data on emulsification time, visual acuity (pre- and post-removal), mean intraocular pressure (IOP), and clinical outcomes were collected and analyzed using the Statistical Package for Social Sciences (SPSS) software (IBM SPSS Statistics, Armonk, NY). The results were graphically presented with mean, standard deviations, frequencies, and proportions. Results A total of 158 patients underwent silicone oil removal after undergoing primary vitrectomy for RRD with silicone oil. The mean age of the patients was 45.90 ± 17.8 years. The mean preoperative intraocular pressure (IOP) among the patients was 16.28 ± 2.97 mmHg. Post removal of silicone oil, the IOP was reduced to 12.66 ± 3.02 mmHg. In 11 out of 158 cases (6.9%) of RRD, emulsification had occurred with silicone oil 5000 cs. We found that out of 11 cases of emulsification, eight (72.73%) were 40 years or older in age. Seven (63.64%) patients had tamponade duration of 10 weeks or longer. However, the difference was not statistically significant. Conclusion In conclusion, our study found that the incidence of emulsification of 5000 cs silicone oil in the patients who underwent primary vitrectomy for the treatment of RRD was 6.9%. We observed that emulsification was more frequent in patients aged 40 years or older and those with a tamponade duration of 10 weeks or longer, although the difference was not statistically significant. Further investigation with bigger sample sizes and extended follow-up periods is required to verify our findings and explore potential factors that could lead to emulsification in this group of patients.

LONG-TERM MICROVASCULAR REMODELING AND CYSTIC CHANGES AFTER RETINAL DETACHMENT TREATED WITH SILICON OIL TAMPONADE

PURPOSE

To determine the long-term microvascular alterations associated with macular cystic changes after retinal detachment surgery with silicone oil tamponade.

METHODS

The results of two optical coherence tomography angiographies performed at 11 months and 38 months after silicone removal were retrospectively analyzed for 30 eyes. The data were compared between both measurements and between eyes with macular cysts (MC+) and without macular cysts (MC-). Two patterns of cysts were identified and compared: cysts exclusively involving the inner nuclear layer (INLc) and cysts present in all retinal layers.

RESULTS

At both end points, 20 eyes (67%) presented with macular cysts, 12 of them (40%) had INLc. At the first end point, vascular density of superficial capillary plexus was higher and superficial foveal avascular zone was smaller in MC+ eyes than in MC- eyes (P = 0.04 and P = 0.017, respectively). At the second end point, vascular density of superficial capillary plexus significantly decreased in MC+ eyes as compared with the first end point (P < 0.001) and superficial foveal avascular zone enlarged (P < 0.001). Macular central thickness decreased between follow-ups only in eyes with INLc (P < 0.01). The final best-corrected visual acuity was better in eyes with INLc than in eyes with cysts present in all retinal layers (P < 0.01). There was no difference between the final best-corrected visual acuity in eyes with INLc and MC- eyes.

CONCLUSION

Macular cysts are a common finding long after silicon removal. Vascular remodeling seems characterized by an initial increase of the vascular density of superficial capillary plexus in eyes with cysts, which is followed by its progressive decrease. The INLc is the most common pattern of cysts. They are associated with a progressive decrease of the central macular thickness without visual impairment.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Early vascular changes after silicone oil removal using optical coherence tomography angiography

BACKGROUND

This study evaluated the vascular changes in the macular and peripapillary regions before and after silicone oil (SO) removal in patients with rhegmatogenous retinal detachment.

METHODS

This single-center case series assessed patients who underwent SO removal at one hospital. Patients who underwent pars plana vitrectomy and perfluoropropane gas tamponade (PPV + C₃F₈) were selected as controls. Superficial vessel density (SVD) and superficial perfusion density (SPD) in the macular and peripapillary regions were assessed by optical coherence tomography angiography (OCTA). Best-corrected visual acuity (BCVA) was assessed using LogMAR.

RESULTS

Fifty eyes were administered SO tamponade, 54 SO tamponade(SOT) contralateral eyes, 29 PPV + C₃F₈ eyes, and 27 PPV + C₃F₈ contralateral eyes were selected. SVD and SPD in the macular region were lower in eyes administered SO tamponade compared with SOT contralateral eyes (P < 0.01). Except for the central area, SVD and SPD in the other areas of the peripapillary region were reduced after SO tamponade without SO removal (P < 0.01). No significant differences were found in SVD and SPD between PPV + C₃F₈ contralateral and PPV + C₃F₈ eyes. After SO removal, macular SVD and SPD showed significant improvements compared with preoperative values, but no improvements in SVD and SPD were observed in the peripapillary region. BCVA (LogMAR) decreased post-operation and was negatively correlated with macular SVD and SPD.

CONCLUSIONS

SVD and SPD are decreased during SO tamponade and increased in the macular region of eyes that underwent SO removal, suggesting a possible mechanism for reduced visual acuity during or after SO tamponade.

TRIAL REGISTRATION

Registration date: 22/05/2019; Registration number, ChiCTR1900023322; Registration site, Chinese Clinical Trial Registry (ChiCTR).

The long-term outcome of eyes with unexplained visual loss after gas tamponade for macula-on retinal detachment

PURPOSE

To analyze the long-term outcome of eyes suffering from unexplained visual loss after gas tamponade for primary macula-sparing rhegmatogenous retinal detachment (RRD).

METHODS

Cross-sectional analysis of all eyes with macula-on RRD experiencing an unexplained loss of vision after gas reabsorption that were treated and followed from 2010 to 2019. The investigational work-up included: best-corrected visual acuity (BCVA), clinical examination, spectral-domain optical coherence tomography (SD-OCT) and automated computerized perimetry.

RESULTS

The 9 eyes of the 9 patients were analyzed after 5.9±2.4 years. BCVA improved by 0.54±0.50 logMAR from baseline, achieving a final value of 1.17±0.52 logMAR (∼20/320; p=0.0115). The thicknesses of the macula, of the macular ganglion cells and of the retinal nerve fiber layers were unchanged compared to the baseline, as well as the rate of ellipsoid zone defects (22.2%). The proportion of eyes with microcystoid macular edema (MME) significantly decreased to 44.4% (p=0.0294). Perimetry mean deviation increased from a baseline value of -18.06±2.72 to -17.23±2.29 dB (p=0.0390), with an unchanged pattern standard deviation (p=0.1289). In general, a reduction of the scotomata relative depth from baseline was evident in all eyes.

CONCLUSIONS

Eyes with macula-on RRD suffering from unexplained visual loss after gas reabsorption, despite disclosing an overall unchanged structural macular morphology, showed a moderate, but significant, visual and perimetric improvement in the long-term.

Unexplained visual loss after primary pars-plana-vitrectomy with silicone oil tamponade in fovea-sparing retinal detachment

BACKGROUND

To investigate the incidence and clinical characteristics of unexplained visual loss in patients with fovea-sparing rhegmatogenous retinal detachment (RRD) during or after silicone oil (SO) tamponade.

METHODS

The medical charts of all patients with macula-on RRDs, who underwent pars-plana-vitrectomy (ppV) with SO tamponade were retrospectively assessed regarding unexplained visual loss (UVL) of ≥ 3 Snellen lines and alterations on optical coherence tomography (OCT) during or after SO tamponade. The clinical data analysed included visual acuity, surgical parameters, OCT images, duration of SO tamponade and the time point of visual decline. Cases with re-detachment or secondary causes of visual loss such as SO emulsification, epiretinal membranes or macular edema were excluded.

RESULTS

Over a 15-year-period, 22 cases with macula-on RRD, which had primarily been treated with ppV and SO tamponade, met the inclusion criteria. In most eyes (n = 20; 91%), the RRD was caused by a giant retinal tear (GRT). In 11 of these 22 cases (50%), best-corrected visual acuity (BCVA) had dropped by at least 3 lines for no apparent reason. In these 11 cases, mean preoperative logMAR BCVA was 0.2 (SD 0.13; range 0-0.5), equal to Snellen's VA of 0.63, and mean postoperative logMAR BCVA 1.0 (SD 0.24; range 0.5-1.3), equal to Snellen's VA of 0.10. Visual decline occurred about 12 weeks postoperatively (SD 6.2; range 3-20 ) and comprised 8 lines (SD 2.3; range -11 to -4). SO was removed on average 139 (SD 50.0; range 88-271) days after the first ppV. In 9 cases visual decline occurred while the SO was in-situ. In 2 patients, BCVA decline was noted 2 weeks after SO removal. In all eyes, preoperative central foveal thickness (CFT) was 254 μm (SD 24.2), which decreased to 224 μm (SD 29.6) during SO tamponade and increased to 247 μm (SD 29.2) after SO removal, irrespective of the presence of UVL. The mean follow-up time was 20 months (SD 30.6) after SO removal.

CONCLUSION

UVL after SO tamponade for macula-on RRD is more frequent than expected. The incidence in our case series was 50%. The mechanism of this phenomenon is still unknown. In general, vitreoretinal surgeons should thoroughly question the need for SO tamponade, inform their patients of possible UVL and remove SO as early as possible.

TRIAL REGISTRATION

The study was approved by the local ethics committee on 6th of May 2022 (Ethikkommission der Universität Regensburg, Votum 22-2925-104) and was conducted in accordance with the ethical standards of the Declaration of Helsinki.

Effect of silicone oil on retinal microcirculation after vitrectomy for rhegmatogenous retinal detachment evaluated by OCT angiography: a literature review

Silicone oil (SO) has been widely used as intravitreal tamponade agent for rhegmatogenous retinal detachment (RRD) and has been occasionally associated with incomplete retinal structural and functional recovery. The use of Optical Coherence Tomography Angiography (OCT-A) has recently attracted significant attention for detailed analysis of retinal capillary plexus and blood flow changes as predicting factors for postoperative outcomes. A detailed literature search was performed in PubMed database until October 2022. The following keywords were used: rhegmatogenous retinal detachment, silicone oil, optical coherence tomography angiography, macular microvasculature, peripapillary capillary plexus, vessel density, and foveal avascular zone. We identified and reviewed 19 studies referring to microcirculation alterations of the retinal capillary plexus as seen on OCT-A in eyes treated by vitrectomy with intravitreal SO for RRD. A comprehensive update revealed variability of microcirculation characteristics of the retinal capillary plexus including the macular and the peripapillary capillaries. Further studies are warranted to clarify the OCT-A values in an attempt to identify the potential effect of SO on retinal tissue in clinical practice. A review of the existing literature sheds light on the effect of SO on retinal capillary plexus and the potential impact on functional outcomes after vitrectomy for RRD. This article discusses important aspects of key publications on the topic, highlights the importance to identify distinct alterations of the microvasculature status, and proposes the need for further future research in this field.

Assessment of Silicone Oil Emulsification: A Comparison of Currently Applied Methods

Purpose

To compare ultrasound biomicroscopy (UBM), Coulter counter, and B-scan ultrasonography in the evaluation of silicone oil (SO) emulsification.

Methods

Patients who underwent primary pars plana vitrectomy with SO tamponade for rhegmatogenous retinal detachment and SO removal were included. UBM images were acquired before the SO removal, and B-scan images were taken after removal. The number of droplets in the first and last 2 mL of washout fluid was analyzed using a Coulter counter. The correlations between these measurements were analyzed.

Results

Thirty-four eyes received both UBM and Coulter counter analysis for the first 2 mL of washout fluid, and 34 underwent B-scan and Coulter counter analysis of the last 2 mL washout fluid. The mean UBM grading was 26.41 ± 9.71 (range: 1-36); the mean SO index obtained with B-scan was 5.25 ± 5.00% (range: 0.10-16.49%), and the mean number of SO droplets was 1.26 ± 2.45 × 10⁷/mL and 3.34 ± 4.22 × 10⁶/mL in the first and last 2 mL of washout fluid, respectively. There were significant correlations between UBM grading and SO droplets in the first 2 mL and between B-scan grading and SO droplets in the last 2 mL (all P < 0.05).

Conclusions

UBM, Coulter counter, and B-scan ultrasonography could all be used in the evaluation of SO emulsification, and their findings were comparable.

Retinal and Corneal Changes Associated with Intraocular Silicone Oil Tamponade

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

[Visual acuity reduction and silicone oil tamponade]

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

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.

Risk factors for epiretinal membrane in eyes with primary rhegmatogenous retinal detachment that received silicone oil tamponade

Background/aims

This study investigated the risk factors for epiretinal membrane (ERM) in eyes with primary rhegmatogenous retinal detachment (RRD) that received silicone oil (SO) tamponade.

Methods

This retrospective analysis included 1140 patients (1140 eyes) with RRD who underwent primary vitrectomy and SO tamponade. The prevalence of ERM was estimated and possible risk factors (eg, type 2 diabetes, proliferative vitreoretinopathy (PVR), SO tamponade time (SOTT), photocoagulation, vitreous haemorrhage, choroidal detachment, cryotherapy and retinal tear size) were analysed via multiple logistic regression.

Results

The prevalence of ERM was 12.3% (140/1140), and the accuracy of preoperative ERM diagnosis was 40.5%. Multivariate logistic regression analysis showed that risk factors for ERM in eyes with SO tamponade included preoperative PVR (OR=4.336, 95% CI 2.533 to 7.424, p<0.001), type 2 diabetes (OR=3.996, 95% CI 2.013 to 7.932, p<0.001), photocoagulation energy (OR=1.785, 95% CI 1.306 to 2.439, p<0.001) and SOTT (OR=1.523, 95% CI 1.261 to 1.840, p<0.001). No statistically significant associations were observed between the incidence of ERM and other risk factors. Preoperative PVR showed the strongest association with risk of ERM. The risk of ERM was positively associated with SOTT, photocoagulation energy and preoperative PVR grade.

Conclusion

In eyes with RRD that received SO tamponade, the prevalence of ERM was 12.3%, while the accuracy of preoperative ERM diagnosis was low. Preoperative PVR, type 2 diabetes, photocoagulation energy and SOTT were the main risk factors for ERM.

Longitudinal evaluation of retinal thickness and OCTA parameters before and following silicone oil removal in eyes with macula-on and macula-off retinal detachments

BACKGROUND

To investigate the longitudinal retinal vascular and structural alterations by using OCTA following successful repair of retinal detachment (RD) by using silicone oil (SO) endotamponade.

METHODS

A prospective cohort study was performed on 24 eyes of 24 subjects; 17 of them with macula-off and seven with macula-on RD. At least four OCTA scans were generated for each study eye; two before and two after SO removal (SOR). At each session, retinal thickness (RT), vascular density (VD) in the superficial (SCP) and deep capillary plexuses (DCP) and foveal avascular zone(FAZ) size were measured within the fovea, parafovea and whole macular image. The changes in repeated measures of the same parameters especially before and after SOR were performed and compared within macula-on and macula-off groups and between fellow eyes.

RESULTS

"In the macula-off eyes, RT measurements within the whole macula, fovea and parafovea reduced as compared with their fellow eyes(p < 0.0001, p = 0.001 and p < 0.0001, respectively) and did not improve after SOR. Additionally, all of the whole macular, foveal, and parafoveal VD measurements at SCP and foveal VD at DCP were less than their fellow eyes after SOR (p = 0.026, p = 0.023 p = 0.026, and p = 0.002, respectively). In macula-on eyes, RT measurements decreased within the parafovea and whole macular area before SOR (p = 0.018 and p = 0.011, respectively) but improved after SOR. Also, VD measurements did not change during follow-up and were not statistically different than their fellow eyes (p > 0.05). FAZ enlargement was found in eyes with macular-off RD after SOR, whereas it was not observed with macular-on RD (p = 0.038and p = 0.237, respectively).

CONCLUSIONS

Treatment of macula-off RD with SO tamponade has been associated with vascular retinal abnormalities which did not improve following SOR. On the contrary, successful treatment of RD with SO tamponade in macula-on eyes VD measurements of SCP and DCP were not statistically different than their fellow eyes.

Macular microcirculation changes after macula-off rhegmatogenous retinal detachment repair with silicone oil tamponade evaluated by OCT-A: preliminary results

Background:

Rhegmatogenous retinal detachment (RRD) with macular involvement is a sight-threatening condition. Silicone oil (SO) is efficacious for retinal tamponade, especially in complex cases. Whether macular detachment per se or the potential tamponading agent may affect macular microcirculation after RRD repair is a matter of research.

Objectives:

To investigate macular microcirculation changes using optical coherence tomography angiography (OCT-A) after pars plana vitrectomy (PPV) with intravitreal SO for RRD repair in the early posttreatment period.

Design:

Prospective comparative cross-sectional study.

Data sources and Methods:

Fourteen eyes of 14 patients were included in the study. All eyes underwent a single successful PPV with SO tamponade for macula-off RRD. OCT-A was performed to analyze macular microcirculation and visual outcomes at 1 month postoperatively. The fellow unaffected eye was used as control.

Results:

Vessel density (VD) in the superficial capillary plexus (SCP) was significantly lower at each macular region (fovea, parafovea, and perifovea) of SO-treated eyes compared with the fellow eyes (all p = 0.001). Similarly, perfusion density (PD) in the SCP was significantly lower at each macular region than the fellow eyes (all p = 0.001). There was enlargement of foveal avascular zone (FAZ) area and decrease of circularity at RRD eyes compared with the fellow ones (all p = 0.001). Postoperative logMAR visual acuity (VA) was significantly lower in treated eyes than fellow eyes and correlated inversely with foveal, parafoveal, and perifoveal VD and PD SCP (all p < 0.001). Postoperative VA had no correlation with FAZ parameters.

Conclusion:

Enlargement of FAZ SCP and decrease in VD and PD SCP during the short-term follow-up were possibly attributable to ischemic changes in the macular area after RRD repair with SO tamponade. In this preliminary study, the flow density in macular capillary plexus may represent an indicator of visual outcomes.

What Is the Cause of Toxicity of Silicone Oil?

Purpose: To investigate the toxicity of the low-molecular-weight components (LMWCs) in ophthalmic silicone oils (SilOils) on retinal cell lines. Methods: The toxicity of six types of LMWCs were studied and compared with conventional SilOil 1000 cSt. In vitro cytotoxic tests of LMWCs, in both liquid and emulsified forms, on three retinal cell lines (Müller cells (rMC-1), photoreceptor cells (661W) and retinal pigment epithelial cells (ARPE-19)) were conducted using a transwell cell culturing system. The morphology and viability of cells were assessed by light microscopy and Cell Counting Kit-8 (CCK-8) assay at different time points (6, 24 and 72 h). The ARPE-19 apoptotic pathway was investigated by Mitochondrial Membrane Potential/Annexin V Apoptosis Kit at different time points (6, 24 and 72 h). Results: Apart from dodecamethylpentasiloxane (L5), all liquid LMWCs showed varying degrees of acute cytotoxicity on retinal cell lines within 72 h. Emulsified LMWCs showed comparable cytotoxicity with liquid LMWCs on retinal cell lines. Cyclic LMWCs, octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) had significantly higher cytotoxicity when compared with their linear counterparts decamethyltetrasiloxane (L4) and L5 with similar molecular formula. Using ARPE-19 cells as an example, we showed that LMWCs induce the apoptosis of retinal cells. Conclusions: Most LMWCs, in both liquid and emulsified forms, can induce acute cytotoxicity. In addition, cyclic LMWCs are suspected to have higher cytotoxicity than their linear counterparts. Therefore, LMWCs are suspected to be the main cause of the long-term toxicity of ophthalmic SilOil, due to their toxicity and propensity to cause ophthalmic SilOil to emulsify. The amount of LMWCs should be considered as the paramount parameter when referring to the quality of SilOil.

DIA Comparative Proteomic Analysis of Retro-oil Fluid and Vitreous Fluid From Retinal Detachment Patients

Objectives: There have been reports of unexplained visual loss following intra-ocular silicone oil (SiO) tamponade in retinal detachment patients, yet the underlying mechanism is unknown. The aim of this study was to investigate the mechanisms behind retinal toxicity following intra-ocular SiO tamponade in retinal detachment patients. Methods and Results: Vitreous fluid samples were acquired from 27 patients (27 eyes). Twelve eyes for data-independent acquisition (DIA) were divided into four groups: pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment (RD group), SiO removal after successful retinal reattachment (SO group), cataract surgery after successful retinal reattachment with sterilized air tamponade (FA group), and PPV for epiretinal membrane (ERM group). The remaining 15 eyes were used for enzyme-linked immunosorbent assay analysis. DIA was combined with two-dimensional liquid chromatography-tandem mass spectrometry to find expression changes in the proteome of vitreous. Mean number mass spectra, statistically differentially expressed proteins, gene ontology (GO), pathway representations, and protein interactions were analyzed. GO analysis showed that the protein categories of synapse organization, cell adhesion, and regulation of cell migration in the SO group were differentially expressed compared to the control or FA groups (p < 0.05). Through Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, lysosome and cell adhesion were found to be significantly enriched in the SO group compared to the FA and control groups (p < 0.05). Cadherin 2, transferrin, and lysosome function may partially contribute to silicone oil-related vision loss. Conclusion: Vision loss-inducing novel molecular signatures and pathways that may be associated with SiO toxicity were identified. Transferrin may be a potential visual outcome biomarker for SiO tamponade.

Effect of Duration of Silicone Oil Tamponade on Retinal Structure after Rhegmatogenous Retinal Detachment Surgery

PURPOSE

The aim of the study was to investigate the effect of tamponade duration on retinal changes induced by silicone oil (SO) in patients who underwent successful rhegmatogenous retinal detachment (RRD) surgery.

METHODS

Retrospective comparative case series of 68 patients who underwent SO tamponade for RRD. Patients were divided into 2 groups based on timing of SO removal: <6 months (group 1, n = 34) versus ≥6 months (group 2, n = 34). The main outcome measure was the change in central macular, inner, and outer retinal layer thickness (CMT, IRLT, and ORLT) before and after SO removal (SOR).

RESULTS

The median tamponade duration was 4 [Clin Ophthalmol. 2016;10:471-6, Zhonghua Yan Ke Za Zhi. 1997 Jan;33(1):39-41] months in group 1 and 8 [Arch Ophthalmol. 1994 Jun;112(6):778-85, Retina. 2004 Dec;24(6):871-7] months in group 2 (p < 0.001). The mean CMT significantly increased from 245.3 ± 22.2 μm and 238.8 ± 41.6 μm under SO to 281.3 ± 60.2 μm and 259.0 ± 43.5 μm after SOR in group 1 (p = 0.009) and in group 2 (p = 0.007), respectively. Automated segmentation measurement revealed a significant increase in mean IRLT (p = 0.014 and p = 0.013) but no change in mean ORLT (p = 0.080 and p = 0.257) in both groups. After adjustment, there was no difference between the 2 groups in terms of mean final CMT, IRLT, and ORLT and mean retinal thickness changes after SOR. There was also no correlation between the tamponade duration and macular microstructural changes or visual recovery.

CONCLUSION

SO tamponade causes a thinning of all retinal layers, mainly affecting the inner retinal layer. However, these changes resolved following SO extraction and were not affected by longer tamponade duration.

The effect of silicone oil tamponade on retinal layers and choroidal thickness in patients with rhegmatogenous retinal detachment: a systematic review and meta-analysis

Background

To evaluate the effects of intravitreal silicone oil (SO) on the retinal and choroidal thickness in eyes with rhegmatogenous retinal detachment (RRD).

Methods

A literature search was performed in Web of Science, Scopus, ProQuest, Embase, Clinical Key, Science Direct, Cochrane Library, and Springer, as well as Persian databases, including IranDoc, MagIran, SID, MOH thesis, and MOH articles until June 2020. Two reviewers independently searched and extracted the data.

Results

Sixteen studies (n = 391) met the inclusion criteria. The meta-analysis showed that the SO tamponade could significantly reduce the central macular thickness (CMT) in patients with RRD as compared to gas tamponade WMD = − 14.91; 95% CI: − 22.23, − 7.60; P < 0.001, I² = 71%). No significant change was found in CMT between the eye with SO tamponade (after SO removal) and the fellow healthy eye in patients with RRD (WMD = − 3.52; 95% CI: − 17.63, 10.59; I² = 68.6%). Compared to the preoperative stage, the SO tamponade could significantly reduce the subfoveal choroidal thickness in patients with RRD (WMD = − 18.67, 95% CI: − 30.07, − 1.28; I² = 80.1%). However, there was no significant difference in the subfoveal choroidal thickness before and after SO removal (WMD = − 1.13, 95% CI: − 5.97, 3.71; I² = 87.6%).

Conclusion

The SO tamponade had a significant effect on the reduction of retinal layers and the subfoveal choroidal thickness.

Changes of macular vessel density and thickness in gas and silicone oil tamponades after vitrectomy for macula-on rhegmatogenous retinal detachment

Purpose

To investigate the macular vessel density and thickness in macular-on rhegmatogenous retinal detachment (RRD) after vitrectomy with gas and silicone oil (SO) tamponade.

Methods

Patients with macular-on RRD eyes, treated with a single successful vitrectomy with gas or SO tamponade and a minimum 30 months follow-up, were reviewed. Best-corrected visual acuity (BCVA), macular vessel density and retinal thickness by using optical coherence tomography angiography, were compared to the contralateral eyes.

Results

Sixteen eyes with gas tamponade and 17 eyes with SO tamponade were included in the study. LogMAR best-corrected visual acuity (BCVA) slightly improved from 0.25 ± 0.18 (Snellen 20/36) to 0.17 ± 0.23 (Snellen 20/30) in eyes with gas tamponade, and decreased from 0.30 ± 0.22 (Snellen 20/40) to 0.49 ± 0.28 (Snellen 20/62) in eyes with SO tamponade. The parafoveal vessel densities in superficial vascular complex (SVC) and the corresponding inner retinal thickness (IRT) were similar between the affected eyes and the contralateral eyes in gas tamponade group (P = 0.578, P = 0.943), while significantly reduced in the affected eyes, compared to the contralateral eyes in SO tamponade group (P < 0.001, P < 0.001).

Conclusion

Eyes in SO tamponade group had worse BCVA, lower SVC vessel densities and thinner corresponding IRT after vitrectomy for macular-on RRD, than those in gas tamponade group.

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.

Silicone oil versus gas tamponade for primary rhegmatogenous retinal detachment treated successfully with a propensity score analysis: Japan Retinal Detachment Registry

Background/aims

To compare the effects of silicone oil tamponade (SOT) to that of gas tamponade (GT) on the best-corrected visual acuity (BCVA) after successful vitrectomy for retinal detachment (RD).

Methods

A retrospective, multicentre, nationwide study with RD who were registered in the Japan-RD Registry. All cases with RD treated with successful vitrectomy between February 2016 and March 2017 were studied. A propensity score matching was performed using the preoperative findings as covariates to adjust the relevant confounders. The primary outcome was the estimated mean difference of the postoperative BCVA in 6 months between eyes treated with SOT to those treated with GT.

Results

Of the 3446 cases registered, 2097 cases met the entry criteria. There were 2042 eyes that had GT and 55 eyes that had SOT. Primary success was defined as a reattached retina with no tamponade at 6 months. After propensity score matching, each group contained 40 cases. The preoperative BCVA was 0.966±0.738 logMAR units in the GT group and 1.270±0.945 logMAR units in the SOT group (p=0.177). Six months postoperatively, the BCVA in the GT group was significantly better at 0.309 logMAR units in the GT group than the 0.671 logMAR units in the SOT group (p=0.002).

Conclusions

Even after successful surgery for RD, eyes that experienced SOT had poorer BCVA than eyes treated with GOT. SOT should be considered cautiously.

Precis

Propensity score analysis of eyes with rhegmatogenous RD showed that postoperative vision was worse in eyes treated once with silicone oil than with gas even after completely successful surgery.

Foldable capsular vitreous body implantation for treatment of traumatic retinal detachment: two case reports

Retinal detachment caused by severe ocular trauma is a type of refractory vitreoretinal disease. Current treatment methods include vitrectomy combined with silicone oil tamponade. However, long-term use of silicone oil tamponade has various complications, including a risk of silicone oil dependence that eventually leads to eyeball atrophy and enucleation. Foldable capsular vitreous bodies (FCVBs) offer a good solution for these problems. However, FCVBs have not been used in large-scale clinical applications and few cases have been reported in the published literature. The main use of FCVBs, based on current evidence, is in the treatment of the relatively few (but important) patients whose eyes have no visual potential; the aim of treatment in these patients is globe preservation, rather than restoration of vision. Here, we describe two patients who underwent FCVB implantation. The findings in these patients indicated that FCVBs can effectively support the vitreous cavity and detached retina. FCVB implantation may thus offer a safe and effective method for treatment of severe retinal detachment, avoiding the inconvenience caused by silicone oil dependence and enucleation. To confirm its long-term usefulness in clinical applications, many additional case reports are needed.

UNEXPLAINED VISUAL LOSS AFTER GAS TAMPONADE FOR MACULA-ON RETINAL DETACHMENT: Incidence and Clinical Characterization

PURPOSE

To identify the incidence rate and the clinical characteristics of unexplained visual loss after gas tamponade for primary macula-sparing rhegmatogenous retinal detachment.

METHODS

Retrospective longitudinal analysis of all subjects undergoing vitrectomy with gas for primary macula-on rhegmatogenous retinal detachment from 2010 to 2019. Outcome was the unexplained visual loss evaluated after gas absorption, defined as a loss of vision to less than 20/200 without evident causes. The diagnostic workup was reviewed.

RESULTS

Nine eyes with unexplained visual loss of 357 surgeries were found. The incidence proportion was 2.52 new cases every 1,000 eyes affected by macula-on rhegmatogenous retinal detachment treated with gas per year. All subjects had an absolute central scotoma, with a median postoperative visual acuity of 20/1,600 (counting fingers). Structural findings were consistent with an axonal damage; all eyes had microcystoid macular edema and reduced thickness of both macular ganglion cell and retinal nerve fiber layers. No photoreceptor structural damages were noted.

CONCLUSION

The incidence of unexplained visual loss after gas tamponade for primary macula-on rhegmatogenous retinal detachment is 2.52 new cases every 1,000 eyes per year. This rare complication, which findings are suggestive of an axonal damage within retinal ganglion cells, remains a serious and unexplained concern for vitreoretinal surgeons.

Silicone oil in vitreoretinal surgery: indications, complications, new developments and alternative long-term tamponade agents

Silicone oil (SO) has been used as a long-term tamponade agent in the treatment of complicated vitreoretinal diseases for about half a century, during which time many advances in surgical techniques and technologies have been made. This review summarizes the chemical and physical properties of SO, its indications and complications, including particularly emulsification. The mechanisms and risk factors for emulsification are discussed, as well as novel strategies for its effective removal. Finally, the review focuses on new improved formulations of SO, including research into slow-release pharmacological agents within SO and provides an overview of alternatives to SO for the purpose of long-term tamponade that are being developed.

Microvascular changes on optical coherence tomography angiography after rhegmatogenous retinal detachment vitrectomy with silicone tamponade

Purpose

We aimed to evaluate microvascular changes on optical coherence tomography angiography (OCTA) in patients with rhegmatogenous retinal detachment (RRD) who underwent silicone oil (SO) tamponade and compare changes according to macular involvement.

Methods

This retrospective study included 48 patients with unilateral RRD who underwent vitrectomy and SO tamponade and were stable after SO removal. Control data were obtained from the fellow healthy eye. Ophthalmic examinations, including best corrective visual acuity (BCVA) and OCTA, were conducted. Differences in vascular density (VD) in different sections of the macula and differences in the foveal avascular zone (FAZ) were analyzed between the affected eyes and control eyes. Subgroup analyses according to macular involvement were performed.

Results

Baseline BCVA and duration of SO tamponade were associated with postoperative BCVA (p<0.001, p = 0.03, respectively). The average VD in the deep capillary plexus (DCP) and the VD of the nasal parafoveal area in both the superficial capillary plexus (SCP) and the DCP decreased relative to those in the control eyes (p = 0.026, p = 0.028, and p = 0.031, respectively). The FAZ area in the DCP and in the SCP also increased when compared with that in the controls (p = 0.043, p = 0.002, respectively). In addition, the macular-off RRD group had lower VD in the nasal parafoveal area of the DCP than the macular-on RRD group.

Conclusion

SO tamponade could cause microvascular changes, especially in the nasal parafoveal area. The macular-off RRD group were affected more than the macular-on RRD group.

VISUAL IMPAIRMENT AND MACULAR VASCULAR REMODELING SECONDARY TO RETROGRADE MACULOPATHY IN RETINAL DETACHMENT TREATED WITH SILICON OIL TAMPONADE

PURPOSE

To assess the frequency of macular cysts (MCs) in retinal detachment treated with silicone oil and evaluate their impact on visual acuity and macular vascularization using optical coherence tomography-angiography.

METHODS

Forty-three eyes of 41 patients treated with silicone oil for retinal detachment were retrospectively studied. Best-corrected visual acuity and 6- × 6-mm optical coherence tomography-angiography examination at least 3 months after silicone oil removal were reviewed. In eyes with MCs, cyst area was measured on the en face optical coherence tomography-angiography image using ImageJ. Density of superficial capillary plexus and area of superficial foveal avascular zone were generated by the optical coherence tomography-angiography. Density of deep capillary plexus and deep foveal avascular zone area were measured using ImageJ.

RESULTS

Twenty-five eyes (58%) presented with MCs. Cysts were exclusively located in the inner nuclear layer in 60% of cases. Mean best-corrected visual acuity in the MC group was lower than that of the non-MC group (P = 0.012). Macular cyst area negatively correlated with best-corrected visual acuity (P = 0.0201). Density of superficial capillary plexus was higher in the MC group (P < 0.0001), whereas area of superficial foveal avascular zone was lower (P < 0.0001). Macular cyst area negatively correlated with density of deep capillary plexus (P < 0.001).

CONCLUSION

The incidence of INL-MCs after silicone oil removal is high. These are associated with impaired vision and macular vascular remodeling. We highlight their similarity with the "retrograde maculopathy" phenomenon.

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

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

Unexplained Visual Loss After Silicone Oil Removal: A 7-Year Retrospective Study

Introduction

Unexplained visual loss after removal of silicone oil from the eye has been described. The purpose of this study is to determine the incidence of unexplained loss of visual acuity after SO removal and to provide possible explanations for this phenomenon.

Methods

This retrospective study included patients that underwent vitreoretinal surgery, at Centro Hospitalar São João, between January of 2012 and October of 2018. Inclusion criterion was vitreoretinal surgery in which the chosen endotamponade was SO, followed by removal of SO and exchange with balanced salt solution (BSS) or air. After SO removal, patients with documented loss of best corrected visual acuity (BCVA) on two or more Snellen lines were analyzed and patients in which the cause of the visual loss was identified, namely OHT (intraocular pressure > 21 mmHg), retinal re-detachment, glaucoma, retinal proliferative membrane formation, or corneal decompensation, were excluded. All patients with unexplained visual loss underwent spectral domain optical coherence tomography (SD-OCT) to exclude causes of visual reduction such as cystoid macular edema, epiretinal membrane, or ellipsoid/interdigitation zone disruption. A p value less than 0.05 was considered statistically significant.

Results

A total of 46 eyes underwent SO tamponade and SO removal during the study period. In 34.8% of the cases (n = 16) there was visual acuity loss in at least two Snellen lines. Of 46 eyes, 23.9% (n = 11) showed vision loss due to known secondary causes. Unexplained loss of visual acuity after SO removal occurred in 10.9% of cases. OHT during silicone endotamponade (p = 0.046) and silicone emulsification (p = 0.001) were identified as factors associated with unexplained visual loss after SO removal.

Conclusion

Unexplained loss of visual acuity after SO removal occurred in 10.9% of cases. OHT during silicone endotamponade and SO emulsification were identified as important factors in the ethology of this phenomenon.

Comparison of fundus changes following silicone oil and sterilized air tamponade for macular-on retinal detachment patients

BACKGROUND

To investigate different tamponade effects of intravitreal silicone oil (SO) and sterilized air on macular vasculature and structure after successful retinal repair for macular-on rhegmatogenous retinal detachment (RRD) patients.

METHOD

21 eyes (21 patients) with macular-on RRD underwent single pars plana vitrectomy following intravitreal SO or sterilized air (Gas) tamponade. Optical Coherence Tomography (OCT) and angiography were used to evaluate retinal layer thickness and flow density (FD) changes throughout the observation period of 12 weeks. Retinal layers were segmented into 7 sets: NFL, GCL + IPL, INL, OPL, ONL + IS, OS+RPE and BRM. Macular perfusion system was segmented into superficial and deep capillary plexus flow density (SCPFD, DCPFD), and choriocapillaries plexus flow density (CCPFD).

RESULT

Compared to Gas tamponade, SO tamponade led to more decrease in both superficial and deep retinal blood flow during observation. NFL thickness was found to decrease in both Gas tamponade and SO tamponade eyes. SO tamponade resulted in more pronounced decrease which led to significant intergroup difference. Opposite changing trends were found in GCL + IPL and ONL + IS thicknesses due to different means of tamponade. SO tamponade caused thicknesses of these two segmented layers to decrease, which led to significant intergroup differences. SO tamponade also led to more decrease in INL, OPL thicknesses. No significant intergroup difference of choroidal thickness was observed.

CONCLUSION

Compared to gas, silicone oil could have more negative tamponade effects on both fundus vasculature and structure.

PREOPERATIVE AND POSTOPERATIVE MACULAR SENSITIVITY ASSESSMENT USING MICROPERIMETRY IN EYES UNDERGOING SILICONE OIL REMOVAL

PURPOSE

To evaluate the functional changes on the macula, before and after silicone oil removal (SOR) using microperimetry (MP3) in patients originally operated for macula-off rhegmatogenous retinal detachments.

METHODS

Prospective interventional study, N = 20. All cases underwent complete ophthalmic examination, including determination of Snellen best-corrected visual acuity, indirect ophthalmoscopy, and MP3 for measuring retinal sensitivity. Primary outcome measure was to describe the alterations in the retinal sensitivity on the macula after SOR.

RESULTS

Mean retinal sensitivity increased in 100% patients (20/20) after SOR with a mean value of 97.44 dB. Best-corrected visual acuity after SOR remained unchanged in 90% (18/20) and improved by 2 lines in only 10% patients (2/20). Median retinal sensitivity of central 6° of the macula was 766.95 ± 173.29 dB before SOR and 863.8 ± 181.08 dB after SOR, P < 0.0001. Mean best-corrected visual acuity was 20/40 before SOR (range, 20/30-20/60) (logarithm of the minimum angle of resolution 0.314 ± 0.169) and 20/40 after SOR (range 20/30-20/80) (logarithm of the minimum angle of resolution 0.315 ± 0.159), P = 0.1628.

CONCLUSION

MP3 was found to be a highly sensitive tool in detecting increased retinal sensitivity after SOR, particularly in central 6° of the macula without significant change in best-corrected visual acuity. Hence, MP3 is an important qualitative indicator of visual function.

Silicone oil-associated retinal light exposure under a surgical microscope

PURPOSE

Based on the hypothesis that silicone oil (SO) with a higher refractive index than water induces unexpected vignetting effects during surgeries, we aimed to investigate the relationship between the volume of SO and light intensity using a surgical microscope.

METHODS

Using a light-sensitive paper and model eye filled with varying volumes (0%, 50%, 62.5%, 75%, 87.5% and 100%) of SO, the light intensity of intraocular lens (IOL) with various refractive powers (0, 10 and 20 dioptres) illuminated by a surgical microscope was measured.

RESULTS

Light exposure density with 1.0% coaxial and oblique light was approximately 22-fold higher than that with 0.1% coaxial and oblique light. Further, it was approximately 34-fold higher in eyes with +20 D IOL than in those with no IOL. The density in eyes with 75% SO was the highest among all groups followed by that with 0% SO. Light exposure densities in the eyes with 75% and 0% SO were significantly higher than those with other volumes of SO. In SO-filled eyes, a microscope set with only an oblique light and a filter successfully reduced light exposure.

CONCLUSION

Silicone oil-related vision loss (SORVL) during SO removal surgeries might be due to increased light exposure on the macular retina caused by the SO-associated vignetting effect. SORVL could be prevented by placing a filter in the microscope during SO removal surgeries.

Multifocal electroretinogram in eyes with intravitreal silicone oil and changes following silicone oil removal

PURPOSE

To determine the effect of intravitreal silicone oil (SO) on multifocal electroretinogram (mfERG) and the changes in mfERG following SO removal.

METHODS

Twelve eyes of 12 patients with SO in vitreous cavity with corrected distance visual acuity (CDVA) > 20/200 were prospectively enrolled as cases over a period from July 2016 to June 2018. The fellow normal eyes served as control. The eyes were evaluated with P1 and N1 wave amplitude and implicit time on mfERG at baseline, 1 and 4 weeks after SO removal.

RESULTS

The mean age was 44.9 ± 18.9 (range 18-74) years. The indication for SO injection was retinal detachment (n = 9, three macula-on eyes, six macula-off eyes) and endophthalmitis (n = 3). The median (range) LogMAR CDVA at baseline was 0.54 (0.18-0.78) in cases and did not change post-SO removal (p = 0.29). There was a significant decrease in average P1 and N1 wave amplitude (p = 0.0001 and 0.0001, respectively) and delay in average P1 and N1 wave implicit time (p = 0.0002 and 0.021, respectively) in cases as compared to controls. The macular status and duration of SO tamponade did not have a significant correlation with mfERG parameters. There was a significant increase in average P1 and N1 wave amplitude (p = 0.009 and 0.003, respectively) at 1 week following SO removal but no change in average P1 and N1 wave implicit time (p = 0.41 and 0.37, respectively).

CONCLUSION

mfERG may be reliably performed for the assessment of macular function in SO-filled eyes. Intravitreal SO exerts an insulating effect on the density of the electric potentials.

Retinal Sensitivity before and after Silicone Oil Removal Using Microperimetry

The purpose of the study is to assess the retinal sensitivity, using microperimetry, before and after silicone removal. It included 22 patients admitted for silicone removal after vitrectomy for macula-off retinal detachment. Patients were divided into 2 groups according to the duration of silicone tamponade: Group A: <3 months (included 10 patients), and Group B: 3–6 months (included 12 patients). Retinal sensitivity was tested, using microperimetry, one day before and one month after silicone removal. The best-corrected visual acuity (in LogMAR) significantly improved postoperatively (0.69 versus 1.06 and 0.69 versus 1.07 in Groups A and B, respectively). The mean intraocular pressure (IOP) was 12.89 ± 1.05 mmHg postoperatively versus 14.89 ± 1.76 mmHg preoperatively in Group A (p=0.011) and was 13.33 ± 1.30 mmHg postoperatively versus 15.33 ± 3.11 mmHg preoperatively in Group B (p=0.008). In Group A, the mean postoperative overall retinal sensitivity was 8.70 ± 2.56 dB versus 5.68 ± 2.00 dB preoperatively (p=0.008). In Group B, it was 9.83 ± 3.36 dB versus 7.00 ± 2.55 dB (p=0.002). No statistically significant difference was found between the two groups as regards improvement in overall retinal sensitivity. We concluded that the overall retinal sensitivity significantly increased following silicone removal in both groups. This trial is registered with ISRCTN43187564.

Vitrectomy with silicone oil tamponade for retinal detachment associated with giant retinal tears: Favourable outcomes without adjuvant scleral buckling

PURPOSE

To evaluate the outcomes of pars plana vitrectomy with silicone oil tamponade in the management of retinal detachment associated with giant retinal tears.

METHODS

We reviewed 45 eyes of 42 patients with primary retinal detachment associated with giant retinal tears over 10 years at a tertiary referral centre. Patients underwent 23-gauge vitrectomy without adjuvant scleral buckling by a single surgeon and had follow-up at least 6 months after silicone oil removal.

RESULTS

Mean follow-up was 37 ± 35 months. Seven eyes (16%) had grade C proliferative vitreoretinopathy, and 16 (36%) had a giant retinal tear ≥180° at baseline. The primary reattachment rate was 84%, and the overall final anatomical success rate was 98%. The mean Snellen visual acuity equivalent at the final visit was 20/58. Final visual acuity ≥20/40 was achieved in 64%. The mean duration of silicone oil tamponade was 10.5 ± 4 weeks. By the final visit, silicone oil had been removed from 44 eyes (98%).

CONCLUSION

The high rates of anatomical and functional success support management of giant retinal tears-associated retinal detachment with vitrectomy without adjuvant scleral buckling. Removal of silicone oil at the earliest possible time helps to avoid complications such as keratopathy, glaucoma and visual loss without apparent reason.

Retinal sensitivity following intraocular silicone oil and gas tamponade for rhegmatogenous retinal detachment

PURPOSE

To investigate whether intraocular silicone oil (SO) tamponade is associated with functional changes in patients with both macula-on and macula-off rhegmatogenous retinal detachments (RRDs).

METHODS

Prospective observational cohort study of patients with RRD treated by vitrectomy with gas or SO tamponade at the University Medical Center Utrecht. Outcome was best-corrected visual acuity (BCVA) and retinal sensitivity on microperimetry 2 months after surgery.

RESULTS

In total, 40 eyes were included. There are 10 eyes in each of the following groups: macula-on RRD and gas, macula-on RRD and SO, macula-off RRD and gas, and macula-off RRD and SO. Median retinal sensitivity on microperimetry was decreased following SO tamponade compared to gas tamponade for both macula-on and macula-off RRD (p < 0.037).

CONCLUSION

Foveal sensitivity was decreased in eyes after SO tamponade compared to gas tamponade. These effects were observed in patients with macula-on as well as macula-off RRD. Although further investigation is warranted to validate our results and to study underlying mechanisms, retinal surgeons need to be aware of these findings after the use of SO tamponade.

Macular Changes on Optical Coherence Tomography Before, During, and After Silicone Oil Tamponade for Macula-On Retinal Detachment: A Case Series

Purpose:

Assess changes on spectral domain optical coherence tomography (OCT) before, during, and after removal of silicone oil (SO).

Methods:

Retrospective series of patients who underwent SO tamponade for macula-on rhegmatogenous retinal detachment. OCT scans of the affected eye were taken before, during, and 3 months after SO tamponade. Qualitative assessment of foveal contour and quantitative comparison of OCT parameters (central macular, cube, ganglion cell layer [GCL], and outer retinal thicknesses) were done between 3 time points.

Results:

Ten eyes of 9 patients were included. Flattening of the foveal contour during SO tamponade was completely reversed after SO removal. Average cube and GCL thicknesses decreased with SO tamponade and increased after SO removal ( P = .01 and P = .02, respectively). Outer retinal thicknesses did not vary among 3 time points ( P = .09).

Conclusions:

SO tamponade causes foveal flattening and thinning of the inner retinal layers, which is reversible on removal.