Attaining functional levels of visual acuity after vitrectomy for retinal detachment secondary to proliferative diabetic retinopathy

Single-cell transcriptomics analysis of proliferative diabetic retinopathy fibrovascular membranes reveals AEBP1 as fibrogenesis modulator

The management of preretinal fibrovascular membranes, a devastating complication of advanced diabetic retinopathy (DR), remains challenging. We characterized the molecular profile of cell populations in these fibrovascular membranes to identify potentially new therapeutic targets. Preretinal fibrovascular membranes were surgically removed from patients and submitted for single-cell RNA-Seq (scRNA-Seq). Differential gene expression was implemented to define the transcriptomics profile of these cells and revealed the presence of endothelial, inflammatory, and stromal cells. Endothelial cell reclustering identified subclusters characterized by noncanonical transcriptomics profile and active angiogenesis. Deeper investigation of the inflammatory cells showed a subcluster of macrophages expressing proangiogenic cytokines, presumably contributing to angiogenesis. The stromal cell cluster included a pericyte-myofibroblast transdifferentiating subcluster, indicating the involvement of pericytes in fibrogenesis. Differentially expressed gene analysis showed that Adipocyte Enhancer-binding Protein 1, AEBP1, was significantly upregulated in myofibroblast clusters, suggesting that this molecule may have a role in transformation. Cell culture experiments with human retinal pericytes (HRP) in high-glucose condition confirmed the molecular transformation of pericytes toward myofibroblastic lineage. AEBP1 siRNA transfection in HRP reduced the expression of profibrotic markers in high glucose. In conclusion, AEBP1 signaling modulates pericyte-myofibroblast transformation, suggesting that targeting AEBP1 could prevent scar tissue formation in advanced DR.

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.

Predictors of visual outcome after pars plana vitrectomy secondary to proliferative diabetic retinopathy

Objective: Advanced proliferative diabetic retinopathy can lead to serious ophthalmological complications, including blindness. This research aimed to determine visual outcomes after pars plana vitrectomy secondary to proliferative diabetic retinopathy, as well as to identify its predictors. Methods: This prospective clinical study was performed in the Ophthalmology Clinic of the Clinical Centre University of Sarajevo. 60 subjects (eyes) with performed pars plana vitrectomy secondary to proliferative diabetic retinopathy were included in the study. Results: After univariate linear regression analysis, glucose, HbA1c, vascular endothelial growth factor, previous pan-retinal laser photocoagulation, baseline best corrected visual acuity, gas injection, vitreous haemorrhage, iris rubeosis, and glaucoma were found to be statistically significant parameters associated with postoperative visual outcome (p<0.05). Multivariate linear regression analysis was performed to evaluate the association between factors and postoperative best corrected visual acuity. Only intravitreal vascular endothelial growth factor concentration, previous pan-retinal photocoagulation, and gas injection remained statistically significant associated with postoperative best corrected visual acuity (p<0.05). Conclusion: Vitrectomy is an effective treatment for advanced proliferative diabetic retinopathy. Factors correlated with the better visual outcome are good systemic control, previous pan-retinal photocoagulation, low intravitreal vascular endothelial growth factor concentration, younger age, intraoperative internal gas tamponade, combined phacoemulsification and pars plana vitrectomy surgery, and the absence of postoperative complications. Abbreviations: PDR = proliferative diabetic retinopathy, VEGF = vascular endothelial growth factor, TDR = tractional retinal detachment, BCVA = best corrected visual acuity, DR = diabetic retinopathy, RDD = rhegmatogenous retinal detachment, NVG = neovascular glaucoma, BRVO = branch retinal vein occlusion, CBC = complete blood count, DBT = differential blood count, ESR = erythrocyte sedimentation rate, HbA1c = glycosylated hemoglobin, PHACO = phacoemulsification, ILM = internal limiting membrane, PPV = pars plana vitrectomy, IOP = intraocular pressure, PRP = pan-retinal photocoagulation, ETDRS = Early treatment diabetic retinopathy study.

Outcomes and Complications of Pars Plana Vitrectomy for Tractional Retinal Detachment in People With Diabetes: A Systematic Review and Meta-analysis

Importance

Tractional retinal detachment (TRD) occurs in approximately 5% of people with proliferative diabetic retinopathy and poses a threat to vision. Pars plana vitrectomy (PPV) is the treatment of choice for TRD.

Objective

To determine anatomic and functional outcomes of PPV for the treatment of TRD in people with diabetes (dTRD).

Data Sources

MEDLINE and Embase were searched systematically from January 1, 2000, to February 20, 2022. In addition, a reference list of eligible studies were screened.

Study Selection

Eligible studies were those published in English, those reporting outcomes of PPV for dTRD, and those that included more than 25 eyes and with a minimum follow-up of 3 months.

Data Extraction and Synthesis

Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines for data extraction/synthesis were followed, and the National Institute for Health quality assessment tool was used to assess risk of bias. Study eligibility was determined independently by 2 reviewers; data extraction was conducted by 1 reviewer and entries checked for accuracy by another. Data were pooled using a random-effects model.

Main Outcomes and Measures

Main outcomes included rate of failure of retinal reattachment following 1 surgery and final visual acuity (VA). The association of baseline patient characteristics and surgical maneuvers with postoperative surgical outcomes was investigated.

Results

Of the 406 studies identified, 38 (3839 eyes) were eligible and included for analysis. Patients had a median (IQR) age of 52.2 (49.6-55.7) years. In the studies reporting patient sex (31 of 38 studies), 1441 were female individuals (50.1%). The overall failure rate of retinal reattachment after 1 surgery was 5.9% (95% CI, 1.4%-8.3%), and the mean final VA was 0.94 (95% CI, 0.82-1.05) logMAR (approximate Snellen equivalent, 6/53; 95% CI, 6/39-6/71). People with higher preoperative VA achieved higher postoperative vision (0.66 logMAR worse final vision; 95% CI, 0.39-0.84 per 1.0 logMAR worse at baseline; P <.001). On multivariable analysis, no other patient characteristics or surgical variables had a statistically significant association with outcomes.

Conclusions and Relevance

Results of this systematic review and meta-analysis suggest that PPV was an effective strategy to achieve retinal reattachment in people with dTRD. Given that higher preoperative VA was the only factor associated with higher postoperative vision, early intervention should be considered and discussed in detail with patients. Overall, final postoperative VA remains low, and patients should be counseled on the guarded prognosis of dTRD.

The Learning Curve of Surgery of Diabetic Tractional Retinal Detachment-A Retrospective, Comparative Study

Background and Objectives: There are few data in the literature concerning the learning curve of tractional retinal detachment (TRD) surgery. We have analyzed the experience gained by a vitreoretinal surgeon over 10 years. Materials and Methods: A retrospective, comparative study of 34 TRD cases operated using 20G instruments between 2008 and 2011 (group A) and 94 cases operated using 23G instruments between 2015 and 2019 (group B). The preoperative characteristics, the type of endotamponade, and the anatomical and functional success were reviewed. Results: The group A patients had a significantly higher rate of concomitant vitreous hemorrhage (VH) at presentation (64.7% vs. 37.2%) and of non-macular retinal detachments (52.9% vs. 39.3%). The rate of silicone oil endotamponade was high in both groups (76.4% vs. 68.1%), but in group B 25.5% were left without a tamponade (vs. none in group A). A postoperative anatomical success was obtained in 76.5% of eyes in group A and 84.04% of eyes in group B (where it was improved to 89.3% by reinterventions). The presenting visual acuity (VA) was very low in both groups (0.01 and 0.05, respectively). The proportion of eyes with improved or stabilized VA was 85.3% in group A and 79.8% in group B (statistically non-significant difference). Conclusions: The anatomical success rate improves quite slowly with increasing surgeon experience and can be further improved by reinterventions. Visual improvement does not match the rate of anatomical improvement. With increasing experience and self-confidence, the surgeon will approach more difficult cases, a fact that may slow down the increase in surgical success rates.

Diagnosis and Management of Fingolimod-Associated Macular Edema

Objective

To investigate the clinical features, treatment, and prognosis of fingolimod-associated macular edema (FAME) and to provide a reference for its rational management.

Methods

FAME-related case reports were included in a pooled analysis by searching Chinese and English databases from 2010 to November 31, 2021.

Results

The median age of 41 patients was 50 years (range, 21, 67 years), of whom 32 were women. The median time to onset of FAME was 3 m (range.03, 120), and blurred vision (17 cases) and decreased vision (13 cases) were the most common complaints. A total of 55 eyes were involved in FAME, including the left eye (14 cases), right eye (10 cases), and both eyes (15 cases), of which 46 eyes had best-corrected visual acuity close to normal (20/12-20/60) and 8 eyes had moderate to severe visual impairment (20/80-20/500). Fundus examination in 23 patients showed macular edema (11 cases). Optical coherence tomography (OCT) in 39 patients mainly showed perifoveal cysts (24 cases), ME (23 cases), and foveal thickening (19 cases). Fundus fluorescein angiography (FFA) in 18 patients showed vascular leakage (11 cases). Complete resolution of ME occurred in 50 eyes and recovery of visual acuity occurred in 45 eyes at a median time of 2 m (range 0.25, 24) after discontinuation of fingolimod or administration of topical therapy.

Conclusions

Macular edema is a known complication of fingolimod. All patients using fingolimod require regular eye exams, especially those with a history of diabetes and uveitis and those undergoing cataract surgery.

PARS PLANA VITRECTOMY WITH and WITHOUT ILM-PEELING for DIABETIC PATIENTS with MACULA INVOLVED TRACTIONAL RETINAL DETACHMENT

PURPOSE

To evaluate the effect of internal limiting membrane (ILM) peeling on anatomical and functional results in pars plana vitrectomy (PPV) performed eyes with tractional retinal detachment affecting the macula due to diabetes mellitus (DM).

METHODS

Patients without ILM peeling were considered as Group 1, and with ILM peeling were considered as Group 2. The main outcomes were the best-corrected visual acuity (BCVA) at 6 months, and the rate of epiretinal membrane (ERM) formation within 6 months. The rate and the indications for resurgery were determined. Parameters affecting final BCVA were determined by regression analysis.

RESULTS

Final BCVA was significantly better in eyes with ILM-peeled off than in eyes with no peel-off (p=0.012). Less secondary ERM was formed in Group 1 (p=0.009). There was no difference between groups in terms of resurgery rates. (p=0.143). The need for resurgery due to ERM was higher in Group 1 rather than Group 2 (p=0.001). The only factor affecting final BCVA was ILM peeling.

CONCLUSION

In patients with tractional retinal detachment affecting the macula due to diabetes, ILM peeling in addition to PPV and membrane excision does not affect the need for resurgery but contributes positively to anatomical and functional outcomes.

The influence of etiology on surgical outcomes in neovascular glaucoma

Background

The authors sought to evaluate visual outcomes in patients with varying etiologies of neovascular glaucoma (NVG), who were treated with glaucoma drainage devices (GDD).

Methods

This was a retrospective case series of patients at a large academic teaching institution who had surgical intervention for neovascular glaucoma between September 2011 and May 2019. Eyes were included if there was documented neovascularization of the iris/angle with an intraocular pressure (IOP) > 21 mmHg at presentation. Eyes must also have been treated with surgical intervention that included a GDD. Primary outcome measure was visual acuity at the 1-year post-operative visit. Secondary outcome measure was qualified success after surgery defined by: pressure criteria (5 mmHg < IOP ≤ 21 mmHg), no re-operation for elevated IOP, and no loss of LP vision.

Results

One hundred twenty eyes met inclusion criteria. 61.7% had an etiology of proliferative diabetic retinopathy (PDR), 23.3% had retinal vein occlusions (RVO), and the remaining 15.0% suffered from other etiologies. Of patients treated with GDD, eyes with PDR had better vision compared to eyes with RVO at final evaluation (p = 0.041). There was a statistically significant difference (p = 0.027) in the mean number of glaucoma medications with Ahmed eyes (n = 70) requiring 1.9 medications and Baerveldt eyes (n = 46) requiring 1.3 medications at final evaluation.

Conclusions

In our study, many patients with NVG achieved meaningful vision, as defined by World Health Organization (WHO) guidelines, and IOP control after GDD. Outcomes differed between patients with PDR and RVO in favor of the PDR group. Different GDD devices had similar performance profiles for VA and IOP outcomes. Direct prospective comparison of Baerveldt, Ahmed, and cyclophotocoagulation represents the next phase of discovery.

High molecular weight hyper-branched PCL-based thermogelling vitreous endotamponades

Vitreous endotamponades play essential roles in facilitating retina recovery following vitreoretinal surgery, yet existing clinically standards are suboptimal as they can cause elevated intra-ocular pressure, temporary loss of vision, and cataracts while also requiring prolonged face-down positioning and removal surgery. These drawbacks have spurred the development of next-generation vitreous endotamponades, of which supramolecular hydrogels capable of in-situ gelation have emerged as top contenders. Herein, we demonstrate thermogels formed from hyper-branched amphiphilic copolymers as effective transparent and biodegradable vitreous endotamponades for the first time. These hyper-branched copolymers are synthesised via polyaddition of polyethylene glycol, polypropylene glycol, poly(ε-caprolactone)-diol, and glycerol (branch inducing moiety) with hexamethylene diisocyanate. The hyper-branched thermogels are injected as sols and undergo spontaneous gelation when warmed to physiological temperatures in rabbit eyes. We found that polymers with an optimal degree of hyper-branching showed excellent biocompatibility and was able to maintain retinal function with minimal atrophy and inflammation, even at absolute molecular weights high enough to cause undesirable in-vivo effects for their linear counterparts. The hyper-branched thermogel is cleared naturally from the vitreous through surface hydrogel erosion and negates surgical removal. Our findings expand the scope of polymer architectures suitable for in-vivo intraocular therapeutic applications beyond linear constructs.