Surgical management of diabetic tractional retinal detachments

Clinical Characteristics and Surgical Outcomes of Patients Undergoing Pars Plana Vitrectomy for Proliferative Diabetic Retinopathy

OBJECTIVE

To evaluate clinical characteristics impacting surgical outcomes of patients undergoing pars plana vitrectomy (PPV) for complications of proliferative diabetic retinopathy (PDR).

DESIGN

Retrospective consecutive observational case series of patients at a large county hospital in Dallas, Texas, from 2014 to 2019.

SUBJECTS

Seven hundred thirty-two patients (933 eyes) undergoing PPV for PDR complications.

METHODS

Collected data included demographics, surgical indication, adjuvant therapies, intraoperative course, complications, and best corrected visual acuity (BCVA). Patients with < 6 months of follow-up were excluded. Best corrected visual acuity was converted to logarithm of the minimum angle of resolution for analysis. Statistics performed included t test, analysis of variance, and multivariate analyses.

MAIN OUTCOME MEASURES

Postoperative BCVA, primary anatomic success rate, and postoperative complications.

RESULTS

Three hundred ninety-three patients were male (509 eyes; 54.5%) with an average age of 52 years. Postoperative BCVA at 6 months was significantly different among surgical indications: 0.79 versus 0.77 versus 1.20 (P < 0.0001) for vitreous hemorrhage (VH), vitreomacular interface abnormalities, and tractional retinal detachment (TRD), respectively. Adjuvant preoperative therapy with panretinal photocoagulation (PRP) versus no PRP (0.95 vs. 1.25; P < 0.001) and insulin versus no insulin (0.99 vs. 1.17; P < 0.01) were associated with improved vision. Iatrogenic breaks were associated with decreased postoperative vision (1.40 vs. 0.88; P < 0.001). The primary anatomic success rate for TRD was 85% (495 eyes). Combined TRD/RRD (tractional and rhegmatogenous retinal detachment) was associated with a lower success rate compared with macula-on/macula-off TRD, with odds ratios of 0.36, 0.46, and 0.53, respectively. Patients experiencing recurrent detachment postsurgery had worse preoperative visual acuity (VA) (1.93 vs. 1.63; P < 0.01) and were younger (47.6 vs. 50.0; P = 0.02). Postoperative complications occurred in 699 eyes (75%), with VH (498 eyes, 53%), cataract (465, 50%), and elevated intraocular pressure (149, 16%) being the most common. Two hundred thirty-six eyes (25%) required a second PPV operation. Endophthalmitis (1 eye; <1%) and choroidal detachment (5 eyes; <1%) were rare.

CONCLUSIONS

In this retrospective series analyzing surgical outcomes among patients with complications from PDR, vitrectomy led to improved vision on average, with a meaningful proportion of patients receiving additional surgical intervention. Surgical indication, presenting VA, age, and adjuvant therapies appeared to impact outcomes.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Intraoperative challenges and management of fibrovascular membrane with tractional retinoschisis in proliferative diabetic retinopathy

BACKGROUND

In severe Proliferative Diabetic Retinopathy (PDR), fibrovascular membrane (FVM) causes macular tractional retinal detachment (MTRD) which threatens vision and eventually leads to blindness. Here we present a case of separation between the inner and outer retina in tractional retinoschisis, induced during intraoperative FVM delamination.

CASE PRESENTATION

A 68-year-old woman presented with PDR in the right eye, characterized by a combined FVM and retinal detachment, for which a vitrectomy was performed. Multiple holes, large retinal detachment extending to all quadrants, and white-lined blood vessels with FVM were found during the procedure. When membrane delamination was performed, it strayed into the space between the inner and outer retinal layers without being noticed due to retinoschisis and multiple retinal holes. After removing the FVM and detaching the separated inner retina, fluid-gas and photocoagulation were performed. Retinal reattachment was successfully achieved after surgery, and the postoperative visual acuity was improved and maintained for 26 months postoperatively.

CONCLUSIONS

When tractional retinoschisis due to FVM is combined with retinal holes in tractional retinal detachment (TRD), care must be taken to prevent delamination from straying into retinoschisis during separation.

Exploration of potential novel drug targets for diabetic retinopathy by plasma proteome screening

The aim of this study is to identify novel potential drug targets for diabetic retinopathy (DR). A bidirectional two-sample Mendelian randomization (MR) analysis was performed using protein quantitative trait loci (pQTL) of 734 plasma proteins as the exposures and clinically diagnosed DR as the outcome. Genetic instruments for 734 plasma proteins were obtained from recently published genome-wide association studies (GWAS), and external plasma proteome data was retrieved from the Icelandic Decoding Genetics Study and UK Biobank Pharma Proteomics Project. Summary-level data of GWAS for DR were obtained from the Finngen Consortium, comprising 14,584 cases and 202,082 population controls. Steiger filtering, Bayesian co-localization, and phenotype scanning were used to further verify the causal relationships calculated by MR. Three significant (p < 6.81 × 10-5) plasma protein-DR pairs were identified during the primary MR analysis, including CFH (OR = 0.8; 95% CI 0.75-0.86; p = 1.29 × 10-9), B3GNT8 (OR = 1.09; 95% CI 1.05-1.12; p = 5.9 × 10-6) and CFHR4 (OR = 1.11; 95% CI 1.06-1.16; p = 1.95 × 10-6). None of the three proteins showed reverse causation. According to Bayesian colocalization analysis, CFH (coloc.abf-PPH4 = 0.534) and B3GNT8 (coloc.abf-PPH4 = 0.638) in plasma shared the same variant with DR. All three identified proteins were validated in external replication cohorts. Our research shows a cause-and-effect connection between genetically determined levels of CFH, B3GNT8 and CFHR4 plasma proteins and DR. The discovery implies that these proteins hold potential as drug target in the process of developing drugs to treat DR.

The Wisconsin silicone oil study (report #1): anatomical and functional outcomes of repair of retinal detachment with proliferative vitreoretinopathy

BACKGROUND

Silicone oil (SO) is a long-term tamponade for repair of complex retinal pathology but has limitations including late redetachment. This study describes our experience with SO tamponade for repair of retinal detachment with proliferative vitreoretinopathy (PVR), with attention to anatomic and functional outcomes.

METHODS

Retrospective consecutive case series of eyes with retinal detachment (RD) complicated by proliferative vitreoretinopathy (PVR) receiving SO tamponade at the University of Wisconsin between 2013 and 2019. Group 1 defined as primary SO placement; Group 2 had SO placed after failing prior retinal detachment repair.

RESULTS

Inclusion criteria of SO placement for repair of RD with PVR was met for 117 eyes. The final reattachment rate was 84% for all eyes, with no difference between Groups 1 and 2. Vision improvement was 2.1 lines for Group 1 (p = 0.06 from baseline) and 4.6 lines for Group 2 (p < 0.0001). The mean number of silicone oil placements was 1.4. Less improvement in vision was noted with repeat SO placement, though overall functional vision of 5/200 or better was achieved in 63.2% of patients.

CONCLUSIONS

SO tamponade allows long-term anatomical stabilisation and substantial vision recovery in eyes with retinal detachment complicated by PVR. Rates of anatomic and functional success have improved significantly when compared to prior studies using oil tamponade for repair of PVR.

The Effect of Steroid Intervention before Vitrectomy for Rhegmatogenous Retinal Detachment Associated with Choroidal Detachment: A Meta-Analysis and Systematic Review

PURPOSE

This meta-analysis discusses the effectiveness of steroid intervention before vitrectomy in patients with rhegmatogenous retinal detachment associated with choroidal detachment.

METHODS

We searched PubMed, MEDLINE, EMBASE, and the Cochrane Library for randomized controlled trials and observational studies published until August 2023. We included studies involving: patients with rhegmatogenous retinal detachment associated with choroidal detachment with proliferative vitreoretinopathy; an experimental group that was not administered steroids and a control group that was administered steroids; and assessment of visual acuity, retinal reattachment rate, and complications. The heterogeneity, publication bias, and sensitivity analysis were performed to ensure the statistical power and reliability of the analysis.

RESULTS

Two randomized controlled trials and four case-control studies involving 490 eyes were included in the meta-analysis. There were no significant differences in the primary and final retinal reattachment rates after surgery between the steroid and non-steroid groups (primary retinal reattachment rate: odds ratio = 1.01, 95% confidence interval = 0.63-1.63, p = .41; final retinal reattachment rate: odds ratio = 0.82, 95% confidence interval = 0.43-1.59, p = .33). There was no statistically significant difference in postoperative visual acuity improvement between the two groups (odds ratio = 1.19, confidence interval = 0.63-2.25, p = .69). In addition, subgroup analyses of different types of steroids showed that systemic and local administration of steroids had similar results for retinal reattachment rate and visual acuity improvement.

CONCLUSION

Patients with rhegmatogenous retinal detachment associated with choroidal detachment who did not receive preoperative steroids achieved the same effect as patients with rhegmatogenous retinal detachment associated with choroidal detachment who did receive preoperative steroids in terms of retinal reattachment rate and visual acuity. It is recommended that patients with rhegmatogenous retinal detachment associated with choroidal detachment undergo surgery as promptly as possible.

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.

Long-Standing Macula-Involving Diabetic Tractional Retinal Detachments with Good Visual Acuity: How Should We Manage These Patients?

Purpose

We assess the merits of pars plana vitrectomy (PPV) in subjects with good visual acuity (VA) and a chronic macula-involving tractional retinal detachment (TRD) secondary to proliferative diabetic retinopathy (PDR).

Methods

A retrospective review of medical records was undertaken. Subjects were divided into 1) a Study Group of subjects who underwent prompt PPV and 2) a Control Group of subjects in which PPV was deferred in favor of less invasive treatment options or observations. Both study and control subjects had a baseline Snellen VA of ≥20/50 and a PDR-associated macula-involving TRD of >6 months duration with a minimum follow-up of 12-months.

Results

There were 58 patients analyzed over an average follow-up period of 27.6 (±7.1) months. The change in VA was similar in the Study Group compared to the Control Group (p=0.94) with both groups losing about three lines of VA during the study period (-0.30 ±0.52 logMAR). Although the rates of maintaining ≥20/200 Snellen VA and ≥20/50 Snellen VA were similar in the Study Group compared to the Control Group (p=0.55 and p=0.28, respectively), the Study Group had more subjects gaining ≥2 lines of VA during the study period (p=0.002).

Conclusion

Patients presenting with good VA and a PDR-associated macula-involving TRD of >6 months were more likely to gain ≥2 lines of VA when PPV was performed at baseline compared to PPV deferral until further deterioration occurred.

The effect of a new design of patient gowns for prone position patients after vitrectomy: A non-randomized, concurrent, controlled study

BACKGROUND

The existing patient clothing is not suitable for patients that have to maintain a prone position for a long time after vitrectomy.

OBJECTIVE

To investigate the effect of a new design of patient gowns for prone position patients after vitrectomy.

METHOD

This study designed a kind of patient's gown for prone position patients. A non-randomized, concurrent, controlled study was conducted on 212 patients who met the inclusion criteria for the prone position after vitrectomy in Grade III at a Class A hospital department of ophthalmology in Zhejiang Province from April to August 2020. The experimental group (106 patients in prone position) and the control group (106 patients in common position) were managed by the same group of nurses. The study recorded and compared the comfort degree of patients' clothing used in the course of operation rehabilitation between the two groups and the satisfaction degree of doctors with nurses to patients' clothing used in the prone position.

RESULTS

The satisfaction degree and comfort degree of patients and the health care providers in the experiment group were significantly higher than those in the control group (p< 0.001).

CONCLUSION

The process of making patient gowns for prone position patients is simple, which can improve the safety and comfort of patients when they were in the prone position. The new design also facilitated the treatment and nursing procedures of the medical staff and improved satisfaction among patients and medical staff.

Comparison of 27-gauge beveled-tip and 25-gauge flat-tip microincision vitrectomy surgery in the treatment of proliferative diabetic retinopathy: a randomized controlled trial

PURPOSE

To compare the effectiveness and safety of a 27-gauge (27G) beveled-tip microincision vitrectomy surgery (MIVS) with a 25-gauge (25G) flat-tip MIVS for the treatment of proliferative diabetic retinopathy (PDR).

METHODS

A prospective, single-masked, randomized, controlled clinical trial included 52 eyes (52 patients) with PDR requiring proliferative membrane removal. They were randomly assigned in a 1:1 ratio to undergo the 27G beveled-tip and or 25G flat-tip MIVS (the 27G group and the 25G group, respectively). During surgery, the productivity of cutting the membrane, the number of vitrectomy probe (VP) exchanges to microforceps, total operation time, vitrectomy time and intraoperative complications were measured. Best-corrected visual acuity (BCVA), intraocular pressure (IOP) and postoperative complications were also assessed to month 6.

RESULTS

Forty-seven eyes (47 patients) completed the follow-up, including 25 in the 27G group and 22 in the 25G group. During surgery in the 27G group, cutting the membrane was more efficient (P = 0.001), and the number of VP exchanges to microforceps was lower (P = 0.026). The occurrences of intraoperative hemorrhages and electrocoagulation also decreased significantly (P = 0.004 and P = 0.022). There were no statistical differences in the total operation time or vitrectomy time between the two groups (P = 0.275 and P = 0.372), but the former was slightly lower in the 27G group. Additionally, the 27G group required fewer wound sutures (P = 0.044). All the follow-up results revealed no significant difference between the two groups.

CONCLUSIONS

Compared with the 25G flat-tip MIVS, the 27G beveled-tip MIVS could be more efficient in removing the proliferative membrane while reducing the occurrence of intraoperative hemorrhages and electrocoagulation using appropriate surgical techniques and instrument parameters. Its vitreous removal performance was not inferior to that of the 25G MIVS and might offer potential advantages in total operation time. In terms of patient outcomes, advanced MIVS demonstrates equal effectiveness and safety to 25G flat-tip MIVS.

TRIAL REGISTRATION

The clinical trial has been registered at Clinicaltrials.gov (NCT0544694) on 07/07/2022. And all patients in the article were enrolled after registration.

Retinotomies and retinectomies: A review of indications, techniques, results, and complications

Retinotomy refers to "cutting" or "incising" the retina, whereas retinectomy denotes "excising" the retina. Retinotomies and retinectomies aid in tackling traction and retinal shortening that persist following membrane dissection and scleral buckling. We performed a literature search using Google Scholar and PubMed, followed by a review of the references procured. All relevant literature was studied in detail and summarized. We discuss the indications of retinotomies and retinectomies for relaxing retinal stiffness, accessing the subretinal space for choroidal neovascular membrane, hemorrhage and abscess clearance, drainage retinotomies to allow retinal flattening, radial retinotomies to release circumferential traction, harvesting free retinal grafts, and prophylactic chorioretinectomies in trauma.

Oxidative Stress and Its Regulation in Diabetic Retinopathy

Diabetic retinopathy is the retinal disease associated with hyperglycemia in patients who suffer from type 1 or type 2 diabetes. It includes maculopathy, involving the central retina and characterized by ischemia and/or edema, and peripheral retinopathy that progresses to a proliferative stage with neovascularization. Approximately 10% of the global population is estimated to suffer from diabetes, and around one in 5 of these individuals have diabetic retinopathy. One of the major effects of hyperglycemia is oxidative stress, the pathological state in which elevated production of reactive oxygen species damages tissues, cells, and macromolecules. The retina is relatively prone to oxidative stress due to its high metabolic activity. This review provides a summary of the role of oxidative stress in diabetic retinopathy, including a description of the retinal cell players and the molecular mechanisms. It discusses pathological processes, including the formation and effects of advanced glycation end-products, the impact of metabolic memory, and involvements of non-coding RNA. The opportunities for the therapeutic blockade of oxidative stress in diabetic retinopathy are also considered.

Clinical Outcomes of 27-Gauge Pars Plana Vitrectomy for Diabetic Tractional Retinal Detachment Repair

Purpose: To analyze the clinical outcomes of 27-gauge pars plana vitrectomy (PPV) repair of diabetic tractional retinal detachment (TRD) of various severities. Methods: This retrospective case series examined the outcomes of 27-gauge PPV to repair diabetic TRD from 2016 to 2020. The effect of medical and ophthalmologic history parameters and baseline detachment characteristics on visual acuity (VA) and retinal reattachment was analyzed. A grading system was established to stage the severity of the baseline vitreoretinal traction or detachment and compare the visual and anatomic outcomes between stages. Results: The study comprised 79 eyes (79 patients). The overall redetachment rate was 10.1% (8/79). The proportion of eyes with severe visual impairment (worse than 20/200) decreased from 81.0% (64/79) preoperatively to 56.9% (37/65) 6 months postoperatively (P < .001). Worse preoperative logMAR VA was associated with greater odds of redetachment (P = .017) and worse postoperative VA (P < .001). Insulin dependence was associated with better VA at 6 months (P = .017). A shorter known duration of diabetes (P = .026) and evidence of neovascularization of the iris (NVI) or angle (P = .004) were associated with worse visual outcomes. Eyes with detachment involving the posterior pole extending beyond the equator had worse VA at 6 months (P = .048). Conclusions: The primary reattachment rate after 27-gauge PPV was 89.9%. There was significant VA improvement, with a roughly 40% reduction in the number of eyes with severe visual impairment by the final follow-up. Insulin dependence, duration of diabetes, presence of NVI before surgery, and baseline posterior pole detachment extending beyond the equator were predictors of visual outcomes.

Factors related to postoperative vitreous hemorrhage after small-gauge vitrectomy in proliferative diabetic retinopathy patients

BACKGROUND

The role of anticoagulation or antiplatelet on post-vitrectomy vitreous hemorrhage (POVH) in patients with proliferative diabetic retinopathy (PDR) is rarely investigated in the small-gauge vitrectomy era. We investigate the relationship between the long-term use of those medications and POVH in a group of PDR patients.

METHODS

A retrospective cohort study was carried out in a group of PDR patients who underwent small-gauge vitrectomy in our center. The baseline data on diabetes, diabetic complications, long-term use of anticoagulants and antiplatelet agents, ocular findings, and vitrectomy details were collected. The occurrence of POVH was recorded during at least three-month follow-up. Factors related to POVH were analyzed using logistic analysis.

RESULTS

During a median follow-up of 16 weeks, 5% (11/220) of patients had POVH, and 75 had received antiplatelet or anticoagulation agents before the operation. Factors related to persistent POVH were the use of antiplatelet or anticoagulation agents (5.98, 1.75-20.45, p = 0.004), the presence of myocardial revascularization (130.65, 3.53-4834.50, p = 0.008), the presence of coronary artery disease (CAD) treated with medicine (56.52, 1.99-1604.06, p = 0.018), and younger age (0.86, 0.77-0.96, p = 0.012). For those receiving preoperative antiplatelet or anticoagulation agents, the probability of developing POVH was higher in the patients whose previous therapy was adjusted compared to those with continued therapy (p = 0.02 by Log-rank test).

CONCLUSIONS

We identified long-term use of anticoagulation or antiplatelet medication, the presence of CAD, and younger age as three independent factors related to POVH. In PDR patients on long-term antiplatelet or anticoagulation medications, particular attention should be given to controlling intraoperative bleeding, and follow-up for POVH should be scheduled.

Chronic ocular small vessel disease: An overview of diabetic retinopathy and its relationship with cardiovascular health

Diabetic retinopathy (DR) is a potentially blinding disease originating from small vessel damage in the retina in chronic hyperglycemic states. DR has a complex multi-pathway driven pathogenesis resulting in diabetic macular edema and retinal ischemia, the former being the most common cause of vision impairment in DR. Hypoxia induced cytokines stimulate vascular endothelial growth factor (VEGF) production and subsequent angiogenesis with resultant mechanical retinal damage over time. Anti-VEGF therapy is effective for the treatment of center-involving diabetic macular edema. There is evolving evidence showing the effectiveness of anti-VEGF as both adjuvant and monotherapy in the treatment of proliferative DR, however laser photocoagulation continues to remain the standard of care. DR in large cohort studies has been shown to be an independent risk factor for the development of cardiovascular disease and mortality. In addition, changes in retinal vascular caliber ratios may have implications for risk of macrovascular events with a gender discrepancy towards women.

Spontaneous Resolution of Tractional Retinal Detachment in a Type II Diabetic Patient

A 43 years old male with diabetes type II was under treatment for diabetic retinopathy with extramacular tractional retinal detachment (TRD) in the left eye OS. During the follow-up visit, the patient had a drop in vision from 20/25 to 20/60. The TRD was found to have progressed to involve the macula and was threatening the fovea; therefore, vitrectomy was thought to be inevitable. Meanwhile, the patient adopted exercise and tight glycemic control, and during the preoperative evaluation of three months duration, we observed resolution of traction and return of visual acuity to baseline (20/20). In conclusion, spontaneous resolution of TRD is extremely rare. If it occurs, the patient may be spared from undergoing a vitrectomy.

Ocular findings, surgery details and outcomes in proliferative diabetic retinopathy patients with chronic kidney disease

Purpose

We investigated the influence of impaired renal function on fundus characteristics, pars-plana vitrectomy (PPV) details, and outcomes in patients with proliferative diabetic retinopathy (PDR).

Design

A retrospective cohort study

Methods

We investigated a consecutive series of PDR patients who underwent PPV. The diabetic complications, previous photocoagulation, intravitreal injections before PPV, ocular findings during PPV, surgical details, short-term visual outcome and post-PPV complications were recorded and compared between patients with and without impaired renal function.

Results

149 patients had normal renal function (67.7%), and 71 (32.3%) patients had impaired renal function; 85.4% of patients were identified with chronic kidney disease (CKD) during the preoperative assessment. Impaired renal function was related to hypertension (3.40[1.58–7.29], p = 0.002), incomplete pan-retinal photocoagulation (PRP) (3.18[1.50–6.72], p = 0.002), severe fibrovascular membrane (8.19[3.43–19.54], p<0.001), and extensive retinal vascular closure (3.40[1.54–7.52], p = 0.002). There was a more frequent occurrence of severe intraoperative bleeding (56.3%, 32.2%, p = 0.001) and a higher percentage of intraocular subretinal fluid drainage (45.1%, 22.1%, p = 0.008) in patients with impaired renal function. The percentage of patients whose visual acuity (VA) increased was similar between the two groups (42.3%, 54.4%, p = 0.34).

Conclusions

In PDR patients, screening for CKD was required before PPV. PDR patients with impaired renal function tended to have more severe ischemic retinal conditions. Comparable PPV outcomes could be obtained in patients with and without impaired renal damage.

An update on the management of diabetic tractional retinal detachment

Background: Tractional retinal detachment (TRD) occurs when contractile forces in the vitreous and neovascular tissue lead to the detachment of the neurosensory retina. The pre-operative use of antivascular endothelial growth factor (anti-VEGF) and advances in microsurgical instrumentation, such as a small gauge vitrectomy (SGV), have improved surgical outcomes.Aim: The purpose of this review is to highlight recent trends in the management of diabetic TRD, supporting earlier surgical intervention and the expanded surgical indications.Methods: PubMed was searched for the following terms: ‘diabetes’ OR ‘diabetic retinopathy’ AND ‘TRD’ AND ‘pars plana vitrectomy (PPV)’ AND ‘anti-VEGF’ AND ‘endophotocoagulation’. Reference lists were reviewed for additional articles. The review was focused on all articles later than 2010 for recent updates on the ever-changing management of this disease entity. No case reports were included in this review article.Results: Management of TRD continues to remain challenging, despite the recent advancements in techniques and instrumentation. Each case needs to be individualised, with careful pre-operative planning, understanding of patient expectations and counselling, coupled with meticulous surgical skills and diligent postoperative management.Conclusion: Management of TRD continues to remain challenging despite recent advances in techniques and instrumentation. Vitrectomy for TRD can improve vision-related quality of life, and the continued evolution and improvement in surgical techniques and adjunctive pharmacotherapy will most likely continue to improve postoperative outcomes.Contribution: The paper presents an overview of current management of tractional retinal detachment in patients with advanced proliferative diabetic retinopathy. 

Intravitreal recombinant tPA before vitrectomy for diabetic tractional retinal detachment: A randomized controlled trial

PURPOSE

To investigate the effect of intravitreal recombinant tissue plasminogen activator (rt-PA) injection before vitrectomy on surgical facility and outcome in diabetic tractional retinal detachments (TRD).

METHODS

Prospective, randomized, interventional clinical trial. A total of 38 eyes with diabetic TRD were candidates for vitrectomy. Patients were randomized 1:1 to receive intravitreal rt-PA, five to seven days before vitrectomy or no injection. Intraoperative surgical facility and anatomic success at month 3 after surgery were assessed.

RESULTS

Mean patient age was 54.2 ± 9.4 years. There was no statistically significant difference between rt-PA and no injection groups with regard to anatomic success (89% versus 95%, respectively, P = 0.547) and best corrected visual acuity at 3 months (2.0 versus 2.1 logMAR, respectively, P = 0.840). However, surgical facility score was statistically significantly lower in rt-PA injection group compared to no injection group (4.1 ± 1.7, 5.8 ± 2.0, respectively, P = 0.007).

CONCLUSIONS

Vitrectomy for TRD was easier after preoperative rt-PA injection, without affecting the anatomic and visual outcomes.

Elevated NLRP3 Inflammasome Levels Correlate With Vitamin D in the Vitreous of Proliferative Diabetic Retinopathy

Purpose: This study aims to determine vitamin D concentrations in the vitreous and serum, as well as the expression levels of NLRP3 inflammasome pathway in the vitreous of patients with proliferative diabetic retinopathy (PDR). In addition, we investigated the possible correlation between NLRP3 inflammasome levels and vitamin D concentrations.

Methods: We obtained vitreous samples before vitrectomy from 55 PDR patients, 25 non-diabetic patients with idiopathic macular hole (IMH), and 10 non-proliferative diabetic retinopathy (NPDR) patients. We also collected serum samples from the same patients. Enzyme-linked immunosorbent assay (ELISA) was used to examine NLRP3 inflammasome pathway proteins, including NLRP3, caspase-1, IL-1β, and VEGF. In addition, vitamin D concentrations were analyzed in Roche Cobas 6000's module e601 platform using electrochemiluminescence immune assay.

Results: The levels of NLRP3 inflammasome pathway and VEGF increased dramatically in PDR vitreous. However, vitamin D concentrations in vitreous and serum followed the opposite trend. Meanwhile, vitreous and serum vitamin D concentrations were significantly negatively correlated with vitreous NLRP3 expression in PDR patients. Moreover, serum and vitreous vitamin D concentrations were positively correlated and demonstrated discriminatory ability in DR. The subgroup analysis of PDR group revealed that eyes with tractional retinal detachment (TRD) had higher NLRP3 inflammasome pathway and VEGF levels but lower vitamin D concentrations. Conversely, eyes that received preoperative pan-retinal photocoagulation (PRP) exhibited lower levels of NLRP3 inflammasome pathway, but vitamin D concentrations were irrelevant to laser treatment.

Conclusions: Our results demonstrate a strong correlation between increased NLRP3 inflammasome pathway and decreased vitamin D concentrations in the vitreous of PDR patients, which may be linked to PDR pathogenesis. In addition, vitamin D supplementation may play a key role in preventing, treating, and improving PDR prognosis due to its inhibitory impact on NLRP3 inflammasome pathway and VEGF.

WIDE-FIELD SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF DIABETIC TRACTIONAL RETINAL DETACHMENTS BEFORE AND AFTER SURGICAL REPAIR

PURPOSE

Wide-field (WF) swept-source (SS) optical coherence tomography angiography (SS-OCTA) was used to image diabetic tractional retinal detachments (TRDs) before and after pars plana vitrectomy. The clinical utility of SS-OCTA was assessed.

METHODS

Patients with diabetic TRDs were imaged prospectively with SS-OCTA. Ultrawide-field imaging was obtained when possible. Postoperative WF SS-OCTA imaging was performed.

RESULTS

From January 2018 through December 2019, 31 eyes of 21 patients with diabetic TRDs were imaged. Wide-field SS-OCTA en-face images captured all areas of TRD and fibrovascular proliferation within the posterior pole that were visualized on ultrawide-field imaging. Optical coherence tomography angiography B-scans revealed the vascularity of preretinal membranes and identified areas of vitreoretinal traction and posterior vitreous detachment. Ten eyes underwent pars plana vitrectomy. Postoperative SS-OCTA imaging demonstrated removal of fibrovascular membranes, relief of traction, and resolution of TRDs. Retinal ischemia before and after surgical repair appeared similar.

CONCLUSION

All clinically relevant features of diabetic TRDs were identified at baseline and assessed longitudinally after pars plana vitrectomy using WF SS-OCTA, which showed resolution of vitreoretinal traction and no apparent change in the status of retinal perfusion after surgery. If the media are clear and fixation is adequate, WF SS-OCTA is likely the only imaging modality needed for the diagnosis and longitudinal evaluation of diabetic TRDs.

The Vitreous Ecosystem in Diabetic Retinopathy: Insight into the Patho-Mechanisms of Disease

Diabetic retinopathy is one of the leading causes of blindness in the world with the incidence of disease ever-increasing worldwide. The vitreous humor represents an extensive and complex interactive arena for cytokines in the diabetic eye. In recent decades, there has been significant progress in understanding this environment and its implications in disease pathophysiology. In this review, we investigate the vitreous ecosystem in diabetic retinopathy at the molecular level. Areas of concentration include: the current level of knowledge of growth factors, cytokine and chemokine mediators, and lipid-derived metabolites in the vitreous. We discuss the molecular patho-mechanisms of diabetic retinopathy based upon current vitreous research.

Experimental models and examination methods of retinal detachment

Retinal detachment refers to the separation of the retinal neuroepithelium and pigment epithelium, usually involving the death of photoreceptor cells. Severe detachment may lead to permanent visual impairment if not treated properly and promptly. According to the underlying causes, retinal detachment falls into one of three categories: exudative retinal detachment, traction detachment, and rhegmatogenous retinal detachment. Like many other diseases, it is difficult to study the pathophysiology of retinal detachment directly in humans, because the human retinal tissues are precious, scarce and non-regenerative; thus, establishing experimental models that better mimic the disease is necessary. In this review, we summarize the existing models of the three categories of retinal detachment both in vivo and in vitro, along with an overview of their examination methods and the major strengths and weaknesses of each model.

Immunological biomarkers of the vitreous responsible for proliferative alteration in the different forms of retinal detachment

Background

The purpose of the study was to explore the immunological components that are responsible for the proliferative alterations in the different forms of retinal detachment (RD).

Methods

Vitreous fluids were collected during 23G pars plana vitrectomy from 54 eyes of 54 patients with different RD types, such as rhegmatogenous RD (RRD) without proliferative vitreoretinopathy (PVR) (n = 30), PVR (n = 16) and proliferative diabetic retinopathy (PDR) with tractional RD (n = 8). Vitreous fluids were obtained from 19 eyes with epiretinal membrane (ERM), which were used as control samples. A multiplex chemiluminescent immunoassay was performed to evaluate the concentrations of 48 cytokines, chemokines and growth factors.

Results

The expression levels of eotaxin, IFN-gamma, IL-6, IL-8, IL-16, MCP-1, MIF and MIP-1 beta were significantly higher in all RD groups than in the ERM group. The levels of CTACK, IP-10, SCGF-beta, and SDF-1 alpha were significantly higher in patients with diabetic tractional RD and PVR than in other patients. The upregulation of VEGF and IL-18 was detected in PDR.

Conclusions

Our results indicate that complex and significant immunological mechanisms are associated with the pathogenesis of different forms of RD: selected cytokines, chemokines and growth factors are upregulated in the vitreous of eyes with RD. The detected proteins are present in different concentrations both in RRD and PVR. In the presence of PVR and PDR, the majority of cytokines are upregulated; thus, they may serve as biomarkers to estimate the progression or severity level of proliferation and later to develop personalized therapeutic strategies to slow down or prevent pathological changes.

Eicosanoid Profiles in the Vitreous Humor of Patients with Proliferative Diabetic Retinopathy

Proliferative diabetic retinopathy is a potentially blinding sequela of uncontrolled diabetes that involves a complex interaction of pro-angiogenic and inflammatory pathways. In this study, we compared the levels of pro-angiogenic arachidonic acid-derived mediators in human vitreous humor obtained from eyes with high-risk proliferative diabetic retinopathy versus controls. The results indicated that lipoxygenase and cytochrome P450-derived eicosanoids were elevated (5-HETE, 12-HETE, 20-HETE, and 20-COOH-AA), and there appeared to be no differences in levels measured in eyes with tractional retinal detachments versus those without. These results provide further insight into the pathogenesis of this disease and for the development of future potential therapeutic agents that target arachidonic acid metabolites to treat diabetic retinopathy.

Effect of Intrasilicone Bevacizumab Injection in Diabetic Tractional Retinal Detachment Surgery: A Retrospective Case-Control Study

Tractional retinal detachment (TRD) causes visual loss in diabetes mellitus patients. Silicone oil can be used as a tamponade to repair retinal detachment; however, intrasilicone injection is challenging. We aimed to evaluate the effect of intrasilicone bevacizumab injection in TRD surgery. This was a single-hospital, retrospective, case-control study of 44 patients (46 eyes). We reviewed medical histories and ophthalmic examination results. We administered silicone oil to 26 eyes (group I), and a combination of silicone oil and intravitreal bevacizumab injection to 20 eyes (group II). The main outcome measures were the logarithm of the minimum angle of resolution (logMAR) visual acuity and central macular thickness. Mean change in logMAR visual acuity was larger (p = 0.029) in group II (−0.99 ± 0.73) than in group I (−0.56 ± 0.80), 12 months postoperatively. Compared to group I, group II exhibited a lower mean (471.54 ± 120.14 μm vs. 363.40 ± 59.57 µm, respectively; p = 0.001), and mean change (−22.39 ± 203.99 μm vs. −72.40 ± 139.35 µm, respectively; p = 0.027), in central macular thickness, 1 month postoperatively. Intrasilicone bevacizumab injection immediately after vitrectomy may rapidly reduce central macular thickness and increase final visual acuity. Prospective studies are necessary to demonstrate long-term safety and efficacy.