Silicone oil insulation effects on flash electroretinogram and visual evoked potential in patients with retinal detachment / Efectos del aislamiento del aceite de silicona sobre el electrorretinograma flash y el potencial evocado visual en pacientes con desprendimiento de retina

Background: Silicone oil is used as endotamponade following vitreoretinal surgery to maintain the retina reattached when indicated. This study investigates the hypothesis that silicone oil causes insulation effects on the retina by affecting its response to light. Methods: Electrophysiological responses to a flash stimulus were recorded using full-field electroretinography (ERG) and visual evoked potentials (VEP). Recordings were performed in 9 patients who underwent surgery for retinal detachment, before (1–2 days) and after (2–3 weeks) silicone oil removal (SOR) in both the study and the control eye. Flash ERG and VEP recordings were performed according to the ISCEV standard protocol. Results: Statistically significant differences were found in the study eye in the amplitudes of the ERG responses and their corresponding ratios, i.e. the amplitude after SOR over the amplitude before SOR, in all conditions tested. No differences were observed in the control eye. The mean ratio of photopic ERG response was 3.4 ± 2.4 for the study and 1.0 ± 0.3 for the control eye (p<0.001). The mean ratio of ERG flicker response was 3.1 ± 2.4 and 1.0 ± 0.3, respectively (p = 0.003). Scotopic flash ERG ratio was 5.0 ± 4.4 for the study and 1.3 ± 0.6 for the control eye (p = 0.012). No differences were observed for the amplitude and latency of flash VEP response after SOR. Conclusions: Silicone oil causes a reduction in flash ERG responses; no effect was found on flash VEP responses. ERGs in eyes filled with silicone oil should not be considered representative of retinal functionality, in contrast to VEPs, which are not affected by silicone oil presence.(AU)

Impact of drainage retinotomy on surgical outcomes of retinal detachment: insights from the Japan-Retinal Detachment Registry.

We investigated the impact of drainage retinotomy on the outcome of pars plana vitrectomy for repair of rhegmatogenous retinal detachment (RRD). This study was a retrospective observational multicenter study. All patients were registered with the Japan-Retinal Detachment Registry. We analyzed 1887 eyes with RRD that had undergone vitrectomy and were observed for 6 months between February 2016 and March 2017. We compared the baseline characteristics and postoperative outcomes between eyes with and without drainage retinectomy. We then performed propensity score matching using preoperative findings as covariates to adjust for relevant confounders. Of 3446 eyes, 1887 met the inclusion criteria. Among them, 559 eyes underwent vitrectomy with drainage retinotomy, and 1328 eyes underwent vitrectomy without drainage retinotomy. After propensity score matching, each group comprised 544 eyes. There was no significant difference between the two groups in BCVA at 6 months after vitrectomy (0.181 vs. 0.166, P = 0.23), the primary anatomical success rate (6.3% vs. 4.4%, P = 0.22), or the rate of secondary surgery for ERM within 6 months (1.5% vs. 1.3%, P = 1.0). Drainage retinectomy does not increase the risk of decreased postoperative BCVA, surgical failure, or secondary surgery for ERM within six months outcomes.

Impact of duration of silicone oil tamponade on foveal and parafoveal thickness in rhegmatogenous retinal detachment: a retrospective cohort study.

PURPOSE: To detect and analyze the influence of the duration of tamponade with silicone oil on the foveal and parafoveal thickness in cases of rhegmatogenous retinal detachment. METHODS: This is a retrospective cohort study of 64 eyes with rhegmatogenous retinal detachment in one eye who underwent pars plana vitrectomy (PPV) with silicone oil injection during the period between January 2019 and December 2021. The patients were divided into 2 groups. Group A with early removal of the silicone oil after 3-4 months and Group B with late removal of the silicone oil (SOR) after 6-8 months. The 2 groups were compared as regards the central foveal (CFT) and parafoveal (PFT) thickness changes from baseline, just before SOR, and after SOR. Changes in best corrected visual acuity (BCVA), relative risk of severe thinning. It was conducted at Kasr Alainy Hospital. RESULTS: 64 eyes were enrolled in the study. Group A included 36 eyes, and group B included 28 eyes. The mean CFT changed insignificantly from 253 ± 52 µm to 252 ± 48 µm after SOR in group A; while it changed significantly from 211 ± 52 µm to 202 ± 46 µm after SOR in group B. The mean PFT decreased insignificantly from 299 ± 39 µm to 297 ± 40 µm in group A, while it decreased significantly from 284 ± 46 µm to 273 ± 44 µm in group B. Lines of improvement of BCVA were 4.11 ± 1.88 in group A, and 2.00 ± 1.24 in group B. Relative risk of severe foveal thinning after SOR was 14.3, and severe parafoveal thinning was 15.43, in group B compared to group A. CONCLUSION: Longer period of silicone oil tamponade may carry a higher risk for severe foveal and parafoveal thinning after silicone oil removal. TRIAL REGISTRATION: The study was registered at clinical trial.gov under the title of (Duration of silicone oil tamponade on foveal and parafoveal thickness in Rhegmatogenous Retinal Detachment) with an ID NCT05817630 at April 2023 "retrospectively registered".

Traumatic terson syndrome with a peculiar mass lesion and tractional retinal detachment: a case report.

BACKGROUND: To report a case with bilateral Terson syndrome presented with a unique mushroom-like mass lesion on the optic disc along with proliferative vitreoretinopathy and tractional retinal detachment. CASE PRESENTATION: A 33-year-old man was injured during a traffic accident and had diffuse brain swelling and intraocular hemorrhage. Poor vision in both eyes was noted after the patient regained consciousness. B-scan ultrasonography showed extensive vitreous opacity with a posterior vitreous detachment and without obvious retinal detachment. Vitrectomy was performed in both eyes five months after the accident. After clearing up the vitreous opacity, a peculiar pigmented mushroom-like mass lesion was noted in the posterior pole and had severe adhesion to the underneath optic disc. Extensive multilayered peripapillary epiretinal membrane was found covering the posterior pole and led to tractional retinal detachment around the macula. The mass was presumed to be an organized vitreous hemorrhage originated from the optic disc. The extensive and adherent epiretinal membrane together with the mass lesion were removed as much as possible and silicon oil was injected for tamponade. However, in the right eye, the retina redetached under silicon oil, whereas in the left eye, his vision improved to 20/100. CONCLUSIONS: Terson syndrome usually has a favorable prognosis but may be complicated by proliferative vitreoretinopathy and tractional retinal detachment. Careful monitoring is warranted and early vitrectomy should be considered in cases suspecting additional pathologies.

Two patients with Knobloch syndrome due to mutation in COL8A1 gene: case report and review of the literature.

BACKGROUND: Knobloch syndrome (KNO, OMIM # 267,750) is a rare ciliopathy group sydrome characterized by a collagen synthesis disorder. It represents an uncommon cause of pediatric retinal detachment. This report presents two cases with different COL18A1 gene mutations, complicated by retinal detachment. CASE PRESENTATION: Both cases exhibited high myopia and various degrees of occipital skull defect. The first case, a female, had bilateral congenital retinal detachment, posterior embryotoxon, and strabismus. The second case, a male, had unilateral congenital retinal detachment and neuromotor developmental delay. The first case, diagnosed in the early months of life, underwent successful retinal reattachment surgery. However, surgery was not performed on the second case, who presented with late-stage unilateral retinal detachment and pre-phthisis. CONCLUSIONS: The report describes two patients with Knobloch syndrome, one of whom responded favorably to surgery for retinal detachment in both eyes. Successful anatomical results were achieved with early surgical interventions. It is essential to recognize the phenotypic and genetic heterogeneity within KNO.

Atopic Dermatitis Associated Retinal Detachment and Retinal Vasculitis: A Case Report.

Atopic dermatitis is usually associated with various ocular complications. We report a 21-year-old Chinese male who presented to our ophthalmology clinic with bilateral retinal detachment and cataracts. The patient had a clear medical history of atopic dermatitis, which had been diagnosed eight years earlier and had been treated with loratadine and pimecrolimus. Cataract surgery was performed for both eyes, combined with scleral buckling for the right eye and pars plana vitrectomy for the left eye. During postoperative follow-up, fundus fluorescein angiography showed retinal vasculitis in both eyes and macular edema in the left eye, which coincided with an exacerbation of atopic dermatitis. Macular edema improved after four months of regular dupilumab treatment in the dermatology department. The ocular condition remained stable three years postoperatively.

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.

Posterior vitreous detachment rates post-uncomplicated phacoemulsification surgery: a systematic review.

PURPOSE: It is commonly accepted that phacoemulsification surgery is a risk factor for the development of posterior vitreous detachment (PVD) and may accelerate the process. This is an important consideration particularly in cases involving young patients who pre-operatively have no PVD, given the increased risk of retinal tears and detachments. METHODS: A comprehensive literature search was conducted to identify studies reporting incidence of PVD post-uncomplicated phacoemulsification surgery. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement was used for search strategy. Of 3071 titles, 7 studies met the inclusion criteria; The outcomes measured were PVD occurrence by (1) time, (2) type, (3) age, (4) gender and (5) axial length, with all statistical analysis performed using Review Manager. RESULTS: A total of 2034 eyes were included for analysis with a mean follow-up time of 28.3 months. 33.3% of patients developed a PVD, either partial or complete, with rates increasing in a time dependent manner. No significant difference was noted in sub-group analysis by age, gender or axial length. CONCLUSIONS: The results from our systematic review show that uncomplicated phacoemulsification accelerates the physiological process of PVD development. Pre-operative evaluation of the vitreoretinal interface should be performed with careful post-operative follow-up advised in those without a pre-existing PVD.

Retinal detachment.

Retinal detachment (RD) occurs when the neurosensory retina, the neurovascular tissue responsible for phototransduction, is separated from the underlying retinal pigment epithelium (RPE). Given the importance of the RPE for optimal retinal function, RD invariably leads to decreased vision. There are three main types of RD: rhegmatogenous, tractional and exudative (also termed serous) RD. In rhegmatogenous RD, one or more retinal breaks enable vitreous fluid to enter the subretinal space and separate the neurosensory retina from the RPE. In tractional RD, preretinal, intraretinal or subretinal membranes contract and exert tangential forces and elevate the retina from the underlying RPE. Finally, in exudative RD, an underlying inflammatory condition, vascular abnormality or the presence of a tumour causes exudative fluid to accumulate in the subretinal space, exceeding the osmotic pump function of the RPE. The surgical management of RD usually involves pars plana vitrectomy, scleral buckling or pneumatic retinopexy. The approach taken often depends on patient characteristics as well as on practitioner experience and clinical judgement. Advances in surgical technology and continued innovation have improved outcomes for many patients. However, even if retinal re-attachment is achieved, some patients still experience decreased vision or other visual symptoms, such as metamorphopsia, that diminish their quality of life. Continued research in the areas of neuroprotection and retinal biology as well as continued surgical innovation are necessary to enhance therapeutic options and outcomes for these patients.

Effect of silicone oil versus gas tamponade on macular layer microstructure after pars plana vitrectomy for macula on rhegmatogenous retinal detachment.

PURPOSE: To analyze structural changes in the macular retinal layers and sub-foveal choroidal thickness (SFCT) in eyes after macula-on rhegmatogenous retinal detachment (RRD) repair by pars plana vitrectomy with either silicone oil (SO) or gas tamponade, and the effect of these changes on visual acuity. PATIENTS AND METHODS: Retrospective study which included 26 eyes in the SO Group and 32 in the Gas Group. Optical coherence tomography (OCT) scans of the affected eyes were obtained before surgery, and 3 months after PPV in the Gas Group, and during silicone oil in situ and 3 months after SO removal, in the SO Group. Qualitative assessment of photoreceptor layer and foveal contour, along with quantitative assessment of macular retinal thickness and SFCT was performed. Postoperative OCT macular microstructural changes were recorded and correlated to corrected distance visual acuity (CDVA). Intraocular pressure (IOP) was measured preoperative and at 3 months post operative. RESULTS: There was a 2-line loss (from 20/28 preoperatively to 20/40 at final follow-up) of CDVA in the SO Group (p=0.051), while there was no statistically significant change in CDVA in the Gas Group (p=0.786). There was no significant correlation between CDVA loss and duration of silicon tamponade (r=-0.031, p=0.893). There was a statistically significant increase in IOP from its baseline to final follow-up of 0.7 mmHg in the SO Group (p=0.023) while there was no statistically significant change in IOP in the Gas Group. During silicone oil tamponade, there was approximately 11% and 5% of retinal and sub-foveal choroidal thinning respectively, which was moderately resolved following silicone oil removal. 20% (5/24) of eyes in the SO Group had qualitative flattening of foveal contour during SO tamponade that resolved after SO removal. CONCLUSION: Thinning of the macula was noticed after macula-on RRD repair with SO tamponade. Such thinning was only partially reversible after the removal of SO.

Anti-inflammatory potential of simvastatin and amfenac in ARPE-19 cells; insights in preventing re-detachment and proliferative vitreoretinopathy after rhegmatogenous retinal detachment surgery.

PURPOSE: Rhegmatogenous retinal detachment is a severe vision-threatening complication that can result into proliferative vitreoretinopathy (PVR) and re-detachment of the retina if recovery from surgery fails. Inflammation and changes in retinal pigment epithelial (RPE) cells are important contributors to the disease. Here, we studied the effects of simvastatin and amfenac on ARPE-19 cells under inflammatory conditions. METHODS: ARPE-19 cells were pre-treated with simvastatin and/or amfenac for 24 h after which interleukin (IL)-1α or IL-1ß was added for another 24 h. After treatments, lactate dehydrogenase release, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) processing, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activity, prostaglandin E2 (PGE2) level, and extracellular levels of IL-6, IL-8, monocytic chemoattractant protein (MCP-1), vascular endothelial growth factor (VEGF), and pigment epithelium-derived factor, as well as the production of reactive oxygen species (ROS) were determined. RESULTS: Pre-treatment of human ARPE-19 cells with simvastatin reduced the production of IL-6, IL-8, and MCP-1 cytokines, PGE2 levels, as well as NF-κB activity upon inflammation, whereas amfenac reduced IL-8 and MCP-1 release but increased ROS production. Together, simvastatin and amfenac reduced the release of IL-6, IL-8, and MCP-1 cytokines as well as NF-κB activity but increased the VEGF release upon inflammation in ARPE-19 cells. CONCLUSION: Our present study supports the anti-inflammatory capacity of simvastatin as pre-treatment against inflammation in human RPE cells, and the addition of amfenac complements the effect. The early modulation of local conditions in the retina can prevent inflammation induced PVR formation and subsequent retinal re-detachment.

[Analysis of the therapeutic efficacy of pars plana vitrectomy without intraocular tamponade in the treatment of high myopic eyes with myopic foveoschisis and central foveal detachment].

Objective: To investigate the efficacy of pars plana vitrectomy (PPV) without intraocular tamponade in the treatment of high myopic eyes with myopic foveoschisis (MF) accompanied by foveal detachment (FD). Methods: A retrospective case series study was conducted. The medical records of patients diagnosed with unilateral MF accompanied by FD at the Eye & ENT Hospital of Fudan University between May 2018 and December 2021 were collected. All patients underwent 23-gauge PPV with posterior vitreous cortex clearance, and no intraocular tamponade was applied. The cases were divided into groups based on whether the internal limiting membrane was peeled during surgery or retained. Follow-up was conducted for at least 12 months. The main outcome measures included postoperative best-corrected visual acuity (BCVA, converted to logarithm of the minimum angle of resolution), central foveal thickness (CFT), MF resolution, and complications. Statistical analyses were performed using t-tests, chi-square tests, Fisher's exact tests, and univariate and multivariate linear regression. Results: A total of 40 patients (40 eyes) with MF and FD were included in the study, with 30.0% being male and 70.0% female. The mean age was (56.9±11.7) years, and the axial length of the eyes was (29.1±1.9) mm. At 12 months postoperatively, BCVA improved from baseline 1.15±0.58 to 0.73±0.39 (t=6.11, P<0.001), and CFT decreased from baseline (610.1±207.2) µm to (155.9±104.1) µm (t=13.47, P<0.001). Complete resolution of MF with foveal reattachment was observed in 80.0% of eyes, with a median time of 6 (5, 8) months. There was no significant difference in BCVA and CFT between the internal limiting membrane peeled group and retained group [0.68±0.39 vs. 0.79±0.40, t=0.85, P=0.403; (148.3±63.8)vs.(164.3±137.2)um,t=0.48, P=0.634]. One eye experienced macular hole and another eye developed retinal detachment postoperatively. Correlation analysis showed a positive correlation between BCVA at 12 months postoperatively and baseline BCVA (ß=0.433, P<0.001). Conclusions: Pars plana vitrectomy without intraocular tamponade is effective in treating MF accompanied by FD. The choice between internal limiting membrane peeling and retention does not significantly affect visual prognosis.

Scleral buckling with adjuvant pneumatic retinopexy versus scleral buckling alone for rhegmatogenous retinal detachment.

To compare the efficacy of scleral buckling with adjuvant pneumatic retinopexy (SB with PR) and scleral buckling (SB) alone for primary rhegmatogenous retinal detachment (RRD). This retrospective and comparative study included patients who underwent SB with PR (n = 88) or SB alone (n = 161) for primary RRD. The primary anatomical success rate for SB with PR was 81.8%, whereas that for SB alone was 80.7% (P = 0.836). Among patients who achieved primary anatomical success, those in the SB with PR group showed postoperative epiretinal membrane (ERM) formation more frequently than those in the SB alone group (11 of 72 [15.3%] vs. 6 of 130 [4.6%]) (P = 0.009). The mean time to subretinal fluid absorption was not significantly different between the SB with PR and SB alone groups (11.2 ± 6.2 vs. 11.4 ± 5.8 months, P = 0.881). In the SB with PR group, retinal detachment involving ≥ three quadrants was a significant risk factor for surgical failure (hazard ratio, 3.04; P = 0.041). Adjuvant pneumatic retinopexy does not provide additional benefit in improving the surgical outcomes of SB for primary RRD repair.

Efficacy of 5-fluorouracil (5-FU) and low molecular weight heparin (LMWH) in high-risk pediatric retinal detachment; randomized clinical trial.

BACKGROUND: Pediatric rhegmatogenous retinal detachments (PRRDs) are complex, rare occurrences and are often related to trauma or congenital abnormalities. Children often do not recognize or report symptoms of retinal detachment. Thus at presentation, PRRD is typically advanced often with macular involvement, proliferative vitreoretinopathy (PVR), chronic duration, and poor visual acuity. Because 5-FU and LMWH are effective in different aspects in the PVR process, it was believed that a syngergistic approach to the prevention of PVR would be advantageous. METHODS: After informed consent, children under 14 years of age with high-risk PRRD underwent pars plana vitrectomy and silicone oil injection with scleral buckle divided into 2 groups in prospective randomized trial. Group A received intraoperative infusion of 5-FU (200 µg/ml) and LMWH (5 IU/ml), group B received infusion of normal saline. Primary outcome was occurrence of recurrent PRRD within 12 weeks, secondary outcomes were occurrence of PVR, best corrected visual acuity (BCVA), number and timing of secondary procedures within 12 weeks. RESULTS: The study included 42 eyes of 41 patients, 21 in group A and 21 in group B, the duration of PRRD ranged from 0.5 to 7 months in group A and 0.25-5 months in group B.The rate of recurrent PRRD was higher in group B 33% compared to 19% in group A (p = 0.292). The mean timing of occurrence of recurrent PRRD was 9.5 ± 5 weeks in group A compared to 2.86 ± 2.41 weeks in group B (p = 0.042), more patients in group B ended up with more advanced PVR (p = 0.038), BCVA was hand movement (HM) only in all cases preoperatively and improved to HM-0.3 Snellen in group A compared to light perception (PL)-0.1Snellen in group B (p = 0.035), there was no difference in any of secondary procedures but with later timing in group A 9.71 ± 3.73 weeks than in group B 4.0 ± 2.83 weeks (p = 0.042). CONCLUSION: This study concluded that the use of the 5-FU and LMWH combination in high risk PRRD resulted in lower rate of postoperative PVR, later recurrence of PRRD and better final BCVA. TRIAL REGISTRATION NUMBER: Registry: clinicaltrials.gov PRS NCT06166914 date of initial release 4/12/2023. Unique Protocol ID: 9,163,209 date 21/10/2021. Retrospectively registered.

Retinal giant cyst treated by the scleral buckling procedure: A case report.

INTRODUCTION: Retinal cysts are rare lesions of the fundus that are essentially fluid-filled cavities located or originating in the retina, with a diameter larger than the normal retinal thickness. To date, there have been few case reports of giant retinal cyst hemorrhage with retinoschisis. CASE PRESENTATION: A 32-year-old woman with no other medical history complained of decreased vision for 3 days after a severe cough. The best-corrected visual acuity in the right eye was 0.5. A comprehensive ophthalmological examination including slit-lamp fundoscopy, ultrasound scan of the eye, optical coherence tomography scan, and orbital magnetic resonance imaging was performed. Ophthalmological examination revealed grade III anterior chamber blood cells and grade III vitreous hemorrhage in the right eye and a large herpetic cyst on the nasal side of the retina. The cyst projected into the vitreous, with a large amount of hemorrhage vaguely visible within it. The cyst was clearly visible, and a superficial retinal limiting detachment was observed around it. Ultrasound showed a retinal cyst with retinal detachment in the right eye. Laboratory test results were unremarkable. After 3 months of conservative treatment, the patient's intracystic hemorrhage was significantly absorbed, but the size of the cyst cavity did not show any significant change. Scleral buckling with external compression combined with external drainage of the intracystic fluid was performed, the patient's visual acuity was gradually restored to a normal 1.0 after the operation, and the retina appeared flattened. The patient was finally diagnosed with a giant retinal cyst with retinoschisis in the right eye. The presumed cause was heavy coughing leading to rupture and hemorrhage of the retinal cyst, similar to the mechanism of rupture of an arterial dissection. To the best of our knowledge, this case of retinal cyst rupture and hemorrhage caused by heavy coughing with good recovery after external surgical treatment has never been reported before. CONCLUSIONS: Giant cystic retinal hemorrhage with retinoschisis is very rare. Orbital magnetic resonance imaging and ocular B-scan ultrasound are essential for its diagnosis, and the selection of an appropriate surgical procedure is necessary to maximize the benefit for affected patients.

Face-down positioning or posturing after pars plana vitrectomy for macula-involving rhegmatogenous retinal detachments.

BACKGROUND: A macula-involving rhegmatogenous retinal detachment (RRD) is one of the most common ophthalmic surgical emergencies and causes significant visual morbidity. Pars plana vitrectomy (PPV) with gas tamponade is often performed to repair primary macula-involving RRDs with a high rate of anatomical retinal reattachment. It has been advocated by some ophthalmologists that face-down positioning after PPV and gas tamponade helps reduce postoperative retinal displacement. Retinal displacement can cause metamorphopsia and binocular diplopia. OBJECTIVES: The primary objective of this review is to determine whether face-down positioning reduces the risk of retinal displacement following PPV and gas tamponade for primary macula-involving RRDs. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (which contains the Cochrane Eyes and Vision Trials Register) (2022, Issue 11), MEDLINE (January 1946 to 28 November 2022), Embase.com (January 1947 to 28 November 2022), PubMed (1948 to 28 November 2022), Latin American and Caribbean Health Sciences Literature database (1982 to 28 November 2022), ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform. We did not use any date or language restrictions in the electronic search. We last searched the electronic databases on 28 November 2022. SELECTION CRITERIA: We included randomized controlled trials (RCTs) in which face-down positioning was compared with no positioning or another form of positioning following PPV and gas tamponade for primary macula-involving RRDs. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodology and assessed the certainty of the body of evidence for the prespecified outcomes using the GRADE approach. MAIN RESULTS: We identified three RCTs (369 eyes of 368 participants) that met the eligibility criteria. Two RCTs provided data on postoperative retinal displacement, one reported on postoperative distortion and quality of life outcomes, two on postoperative best-corrected visual acuity (BCVA) in logMAR, and two on postoperative ocular adverse events such as outer retinal folds. Study characteristics and risk of bias All the trials involved predominantly male participants (range: 68% to 72%). Only one trial provided race and ethnicity information, was registered on a trial registry, and reported funding sources. Using the RoB 2 tool, we assessed the risk of bias for proportion of eyes with retinal displacement, mean change in visual acuity, objective distortion scores, quality of life assessments, and ocular adverse events, with most domains judged to be at low risk of bias. Findings Immediate face-down positioning may result in a lower proportion of participants with postoperative retinal displacement compared with support-the-break positioning at six months (risk ratio [RR] 0.73, 95% confidence interval [CI] 0.54 to 0.99; 1 RCT; 239 eyes of 239 participants; very low certainty evidence). One study found no evidence of a difference in BCVA at three months when comparing postoperative face-up with face-down positioning with or without perfluorocarbon liquid (mean difference [MD] -0.03, 95% CI -0.09 to 0.02; I2 = 0; 56 eyes of 56 participants; very low certainty evidence). Immediate face-down positioning appears to have little to no effect on postoperative distortion scores at week 26 (MD 1.80, 95% CI -1.92 to 5.52; 1 RCT; 219 eyes of 219 participants; very low certainty evidence) and postoperative quality of life assessment scores at week 26 (MD -1.80, 95% CI -5.52 to 1.92; 1 RCT; 217 eyes of 217 participants; very low certainty evidence). Adverse events One study that enrolled 262 participants with macula-involving RRDs suggested that immediate face-down positioning after PPV and gas tamponade may reduce the ocular adverse event of postoperative outer retinal folds at six months (RR 0.39, 95% CI 0.17 to 0.90; 1 RCT; 262 eyes of 262 participants; very low certainty evidence) and binocular diplopia (RR 0.20, 95% CI 0.04 to 0.90; 1 RCT; 262 eyes of 262 participants; very low certainty evidence) compared with support-the-break positioning. Immediate face-down positioning may increase the ocular adverse event of elevated intraocular pressure compared with support-the-break positioning (RR 1.74, 95% CI 1.11 to 2.73; 1 RCT; 262 eyes of 262 participants; very low certainty evidence). Another study found no evidence of a difference in postoperative outer retinal folds when comparing face-down versus face-up positioning at one and three months (RR 1.00, 95% CI 0.50 to 2.02; RR 1.00, 95% CI 0.28 to 3.61; 1 RCT; 56 eyes of 56 participants; very low certainty evidence). No studies reported non-ocular adverse events. AUTHORS' CONCLUSIONS: Very low certainty evidence suggests that immediate face-down positioning after PPV and gas tamponade may result in a reduction in postoperative retinal displacement, outer retinal folds, and binocular diplopia, but may increase the chance of postoperative raised intraocular pressure compared with support-the-break positioning at six months. We identified two ongoing trials that compare face-down positioning with face-up positioning following PPV and gas tamponade in participants with primary macula-involving RRDs, whose results may provide relevant evidence for our stated objectives. Future trials should be rigorously designed, and investigators should analyze outcome data appropriately and report adequate information to provide evidence of high certainty. Quality of life and patient preferences should be examined in addition to clinical and adverse event outcomes.