Retinal Layers Measurements following Silicone Oil Tamponade for Retinal Detachment Surgery

Vision loss associated with silicone oil endotamponade in vitreoretinal surgery - a review

PURPOSE

To clarify the definition, prevalence and classification of different types of unexplained vision loss associated with silicone oil (SO) endotamponades (SO in situ (SOIS) or after removal of SO (ROSO)) in vitreoretinal surgery and identifying the most specific clinical findings and suggesting possible causes.

METHODS

Review of the literature regarding randomized clinical trials (RCTs), retrospective case-control, cohort studies and case series evaluating the risk of using SO, published in English between 1994 and 2023, conducting a computer-based search of the following databases: PubMed, Web of Science, Scopus and Embase. The search was supplemented using the Medline option 'Related Articles' and consulting review articles on the topic.

RESULTS

Findings from reported clinical examinations in SOIS and ROSO are analyzed and finally different theories regarding the underlying pathophysiology are described. From the clinical point of view, findings have been found in OCT, OCTA, microperimetry and electrophysiological studies. Other clearly identifiable causes of vision loss related to the use of SO are listed and commented as differential diagnosis. Finally, the different physiopathological theories of the two types of causes of unexplained vision have been analyzed.

CONCLUSION

Unexpected vision loss under or after SO tamponade (SOIS and ROSO) is a significant concern which is probably underestimated because it is not a clearly defined and known entity. The most frequently described changes were in the ganglion cell complex but this unexpected vision loss remains a serious and unexplained concern for vitreoretinal surgeons and should be identified by clinicians, addressed by manufacturers and reported to Health Authorities as a serious incident according to the new regulation.

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.

Changes in circumpapillary retinal nerve fiber layer thickness after vitrectomy for rhegmatogenous retinal detachment

The study aimed to evaluate the long-term changes in circumpapillary retinal nerve fiber layer (RNFL) thickness after vitrectomy for rhegmatogenous retinal detachment (RRD) repair. A total of 33 eyes of 33 patients were enrolled. By using optical coherence tomography, the circumpapillary RNFL thickness was measured before surgery and 1, 3, 6 months and 1, 2, 3 years after surgery and compared with the preoperative value. The effect of duration, location, and extent of RRD on RNFL thickness change was evaluated. There was a significant increase of circumpapillary RNFL thickness at the 1-month, 3-month [except in the nasal superior sector (P = 0.627)], and only in the nasal inferior sector at 6-month (P = 0.010) follow-up compared with the baseline value (all Ps < 0.05). No significant differences were observed 1, 2, and 3 years after the surgery (P > 0.05). The duration, location, and extent of detachment did not reveal significant correlations with RNFL parameters (P > 0.05). Circumpapillary RNFL thickness in eyes with RRD after vitrectomy demonstrated a transient increase during the early postoperative period. This increase was not associated with duration, location, and extent of RRD. At 3 years following surgery, no RNFL thinning or thickening was observed.

Macular edema after surgical treatment of rhegmatogenous retinal detachment – the possibilities of its prediction

The aim: to develop a mathematical model for predicting macular edema based on the informativeness of clinical and instrumental predictors of its occurrence.Materials and methods. To determine the risk factors for macular edema 64 patients (64 eyes) with macula-off rhegmatogenous retinal detachment complicated by proliferative vitreoretinopathy (grade Cp 1–2) were selected. A retrospective analysis of the surgical treatment results was carried out. The age of the patients ranged from 30 to 81 years (28 women and 36 men).Results. Using regression analysis, two signifi cant factors were identifi ed: the sum of 8 meridians of the visual fi eld before surgery (p = 0.015) and the number of detached quadrants (p = 0.021). Based on the identifi ed factors, a model was obtained for predicting the occurrence of macular edema in the postoperative period for the patients with rhegmatogenous retinal detachment. Conclusion. Based on the analysis of clinical and instrumental indicators in patients with rhegmatogenous retinal detachment, a mathematical model has been developed that allows predicting the occurrence of macular edema in the postoperative period.The application of the proposed prediction model makes it possible to determine the tactics of treatment (peeling of internal limiting membrane) and predict the appearance of macular edema at the preoperative stage.

Retinal Changes before and after Silicone Oil Removal in Eyes with Rhegmatogenous Retinal Detachment Using Swept-Source Optical Coherence Tomography

This study aimed to evaluate and compare the retinal and choroidal thickness and vessel density (VD) changes between silicone oil (SO) tamponade and after SO removal using swept-source optical coherence tomography (SS-OCT) and OCT angiography (OCTA). Thirty patients who underwent pars plana vitrectomy for retinal detachment (RD) with SO tamponade were included. SS-OCT and OCTA were conducted before RD surgery, during SO tamponade, and after SO removal. A 3-dimensional volumetric wide scan protocol was used for the analysis. The segmented retina, choroidal thickness map, and peripapillary thickness were then measured. For the OCTA analysis, 4.5 × 4.5 mm scans were used. Superficial and deep capillary plexus VDs in unaffected fellow eyes and eyes after SO removal were compared. During the SO tamponade period, the thickness of the parafoveal total retina, ganglion cell-inner plexiform layer, and peripapillary retinal nerve fiber layer (ppRNFL) were significantly thinner than those of unaffected fellow eyes (p < 0.05). The parafoveal layer thickness thinning recovered up to three to six months after SO removal. Moreover, six months after SO removal, the parafoveal thickness was not significantly different compared to that of unaffected fellow eyes (p > 0.05). However, the ppRNFL thickness was significantly decreased during SO tamponade and remained unrecovered six months after SO removal. There was no significant difference in the VD on the OCTA. Thus, SO tamponade and removal for RD resulted in a change in the retinal and peripapillary thickness. This may be due to the mechanical pressure effect of SO.

Macular edema risk factors after vitrectomy for rhegmatogenous retinal detachment complicated by proliferative vitreoretinopathy

BACKGROUND: Despite significant advances in the technology of surgical treatment of regmatogenous retinal detachment, a certain proportion of patients with emerging macular edema against the background of silicone oil tamponade remains. AIM: To evaluate the risk factors of macular edema development and to work out a mathematical model for its prediction based on a retrospective analysis of clinical data of patients with rhegmatogenous retinal detachment complicated by proliferative vitreoretinopathy. MATERIALS AND METHODS: A retrospective case series of 64 patients (64 eyes) with regmatogenous retinal detachment complicated by grade CP proliferative vitreoretinopathy who underwent primary retinal detachment repair. Patients were divided into two groups: with the presence of macular edema in the postoperative period and without it (32 patients in each group). In all cases, at the initial examination, retinal detachment involved the macular area. RESULTS: Using regression analysis, two significant factors were identified: the sum of the 8 meridians of the visual field before surgery (p=0.015) and the number of detached quadrants (p=0.021). Based on the identified factors, a model for predicting macular edema occurrence in the postoperative period in the surgical treatment of regmatogenous retinal detachment was obtained. CONCLUSIONS: The investigation results allowed establishing that the retinal detachment area and the sum of the 8 meridians of the visual field are significant pre-operative factors for macular edema development in retinal detachments with proliferative vitreoretinopathy of CP 1-2 degree. The developed mathematical model based on these indicators is characterized by significant information content and allows predicting macular edema occurrence in the postoperative period. The use of the proposed prognostic model determines a differentiated approach to surgical prevention of macular edema and allows making a decision on the removal of internal limiting membrane at the preoperative stage.

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

Background

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

Methods

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

Results

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

Conclusion

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

Effect of silicone oil on peripapillary capillary density in patients with rhegmatogenous retinal detachment

Purpose

To evaluate the effect of silicone oil (SO) on peripapillary blood flow using OCT angiography.

Methods

This prospective case series recruited patients with unilateral rhegmatogenous retinal detachment (RRD) who underwent vitrectomy and SO tamponade. Patients were examined before SO removal and at 10 days, 1 month, and 3 months after SO removal on a spectral domain OCT angiography device (RTVue XR Avanti, Optovue Inc., CA, USA) for the measurement of radial peripapillary capillaries (RPC) vessel density (VD) in global field, superior hemifield, and inferior hemifield. Changes in RPC VD following SO removal were compared between affected eyes and contralateral eyes.

Results

Twenty-two patients were analyzed. The average duration of SO tamponade was 101.3 days (range, 90 to 119 days). After SO removal, global RPC VD increased by 1.3% (95%CI, 0.3 to 2.3%), compared with a − 0.4% (95%CI, − 1.4 to 0.7%) change in contralateral eyes (P = 0.007). The increase in RPC VD after SO removal mainly occurred in the superior hemifield, which was 1.6% (95%CI, 0.6 to 2.7%). The increase in RPC VD in the inferior hemifield was 1.0% (95%CI, − 0.2 to 2.1%) after SO removal.

Conclusions

We detected a mild increase in peripapillary capillary density after SO removal, mainly in the superior hemifield. Our results suggested that SO tamponade could have negative effect on peripapillary blood flow, possibly by capillary compression.

Tamponade in surgery for retinal detachment associated with proliferative vitreoretinopathy

BACKGROUND

Retinal detachment (RD) with proliferative vitreoretinopathy (PVR) often requires surgery to restore normal anatomy and to stabilize or improve vision. PVR usually occurs in association with recurrent RD (that is, after initial retinal re-attachment surgery), but occasionally may be associated with primary RD. Either way, for both circumstances a tamponade agent (gas or silicone oil) is needed during surgery to reduce the rate of postoperative recurrent RD.

OBJECTIVES

The objective of this review was to assess the relative safety and effectiveness of various tamponade agents used with surgery for RD complicated by PVR.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (the Cochrane Library 2019, Issue 1), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to January 2019), Embase (January 1980 to January 2019), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2019), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 2 January 2019.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) on participants undergoing surgery for RD associated with PVR that compared various tamponade agents.

DATA COLLECTION AND ANALYSIS

Two review authors screened the search results independently. We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We identified four RCTs (601 participants) that provided data for the primary and secondary outcomes. Three RCTs provided data on visual acuity, two reported on macular attachment, one on retinal reattachment and another two on adverse events such as RD, worsening visual acuity and intraocular pressure. Study Characteristics Participants' characteristics varied across studies and across intervention groups, with an age range between 21 to 89 years, and were predominantly men. The Silicone Study was conducted in the USA and consisted of two RCTs: (silicone oil versus sulfur hexafluoride (SF₆) gas tamponades; 151 participants) and (silicone oil versus perfluropropane (C₃F₈) gas tamponades; 271 participants). The third RCT compared heavy silicone oil (a mixture of perfluorohexyloctane (F₆H₈) and silicone oil) with standard silicone oil (either 1000 centistokes or 5000 centistokes; 94 participants). The fourth RCT compared 1000 centistokes with 5000 centistokes silicone oil in 85 participants. We assessed most RCTs at low or unclear risk of bias for most 'Risk of bias' domains. Findings Although SF₆ gas was reported to be associated with worse anatomic and visual outcomes than was silicone oil at one year (quantitative data not reported), at two years, silicone oil compared to SF₆ gas showed no evidence of a difference in visual acuity (33% versus 51%; risk ratio (RR) 1.57; 95% confidence interval (CI) 0.93 to 2.66; 1 RCT, 87 participants; low-certainty evidence). At one year, another RCT comparing silicone oil and C₃F₈ gas found no evidence of a difference in visual acuity between the two groups (41% versus 39%; RR 0.97; 95% CI 0.73 to 1.31; 1 RCT, 264 participants; low-certainty evidence). In a third RCT, participants treated with standard silicone oil compared to those receiving heavy silicone oil also showed no evidence of a difference in the change in visual acuity at one year, measured on logMAR scale ( mean difference -0.03 logMAR; 95% CI -0.35 to 0.29; 1 RCT; 93 participants; low-certainty evidence). The fourth RCT with 5000-centistoke and 1000-centistoke comparisons did not report data on visual acuity. For macular attachment, participants treated with silicone oil may probably experience more favorable outcomes than did participants who received SF₆ at both one year (quantitative data not reported) and two years (58% versus 79%; RR 1.37; 95% CI 1.01 to 1.86; 1 RCT; 87 participants; low-certainty evidence). In another RCT, silicone oil compared to C₃F₈ at one year found no evidence of difference in macular attachment (RR 1.00; 95% CI 0.86 to 1.15; 1 RCT, 264 participants; low-certainty evidence). One RCT that compared 5000 centistokes to 1000 centistoke reported that retinal reattachment was successful in 67 participants (78.8%) with first surgery and 79 participants (92.9%) with the second surgery, and no evidence of between-group difference (1 RCT; 85 participants; low-certainty evidence). The fourth RCT that compared standard silicone oil with heavy silicone oil did not report on macular attachment. Adverse events In one RCT (86 participants), those receiving standard 1000 centistoke silicone oil compared with those of the 5000 centistoke silicone oil showed no evidence of a difference in intraocular pressure elevation at 18 months (24% versus 22%; RR 0.90; 95% CI 0.41 to 1.94; low-certainty evidence), visually significant cataract (49% versus 64%; RR 1.30; 95% CI 0.89 to 1.89; low-certainty evidence), and incidence of retina detachment after the removal of silicone oil (RR 0.36 95% CI 0.08 to 1.67; low-certainty evidence). Another RCT that compared standard silicone oil with heavy silicone oil suggests no difference in retinal detachment at one year (25% versus 22%; RR 0.89; 95% CI 0.54 to 1.48; 1 RCT; 186 participants; low-certainty evidence). Retinal detachment was not reported in the RCTs that compared silicone oil versus SF₆ and silicone oil versus to C₃F₈.

AUTHORS' CONCLUSIONS

There do not appear to be any major differences in outcomes between C₃F₈ and silicone oil. Silicone oil may be better than SF₆ for macular attachment and other short-term outcomes. The choice of a tamponade agent should be individualized for each patient. The use of either C₃F₈ or standard silicone oil appears reasonable for most patients with RD associated with PVR. Heavy silicone oil, which is not available for routine clinical use in the USA, may not demonstrate evidence of superiority over standard silicone oil.

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.

SILICONE OIL TAMPONADE EFFECT ON MACULAR LAYER THICKNESS AND VISUAL ACUITY

PURPOSE

To evaluate the influence of silicone oil (SO) tamponade on retinal layers thickness and visual acuity in patients who underwent pars plana vitrectomy for rhegmatogenous retinal detachment.

METHODS

This is a retrospective case series of consecutive patients who underwent pars plana vitrectomy for rhegmatogenous retinal detachment with SO tamponade. Visual acuity and central macular thickness were measured with SO and at least a month after SO removal (SOR). Patients with insufficient or poor-quality images or macular pathologies such as macular edema or epiretinal membranes were excluded.

RESULTS

Forty-one patients with an average age of 56.1 ± 15.2 years were included, and 54% presented with fovea ON. Average tamponade duration was 151 ± 54 days. Central macular thickness of the operated eye increased from 249 ± 50 µm before to 279 ± 48 µm after SOR (P < 0.001), compared with 281 ± 21 µm of the fellow eye (P < 0.001). A mean change of 26 µm was found in the internal layers (P < 0.001). Visual acuity improved from 0.85 ± 0.97 logarithm of the minimal angle of resolution (logMAR; Snellen 20/140) with SO tamponade to 0.34 ± 0.28 logMAR (Snellen 20/43) after SOR (P < 0.001). For patients with fovea ON and without significant cataract, visual acuity was 0.19 ± 0.16 logMAR (Snellen 20/30) at presentation, 0.59 ± 0.41 logMAR (Snellen 20/80) with SO (P = 0.005), and 0.18 ± 0.15 logMAR (Snellen 20/30) after SOR (P = 0.003).

CONCLUSION

Silicone oil tamponade causes a transient decrease in central macular thickness, mainly in the inner layers. After SOR, central macular thickness resembles to the fellow eyes. The mechanism for this effect is unclear, but apparently has no influence on final visual acuity.