EPIRETINAL CELL PROLIFERATION IN MACULAR PUCKER AND VITREOMACULAR TRACTION SYNDROME: Analysis of Flat-Mounted Internal Limiting Membrane Specimens

Choroidal vascularity index changes in different treatments for vitreomacular traction

INTRODUCTION

The aim of this study was to examine if choroidal vascularity index (CVI) is different in eyes with unilateral vitreomacular traction (VMT) from their healthy fellow eyes; and whether different treatments affect the CVI.

METHODS

The baseline and 8-week post treatment CVIs of 56 unilateral VMT patients that underwent spontaneous resolution (n = 30), vitreoretinal surgery (n = 16) or pneumatic vitreolysis (n = 10) were compared with fellow eyes using paired samples t-test. Partial correlation analyses correcting age and gender was used for calculations between treatment groups. P values < 0.05 were considered statistically significant.

RESULTS

The mean baseline CVI for VMT and control eyes had no statistically significant difference (p = 0.81, r= -0.38). The post traction release follow-up CVI of VMT eyes and contralateral eyes had no significant difference (p = 0.12, r = 0.49). In spontaneous resolution group, vitreoretinal surgery group and pneumatic vitreolysis group the baseline and follow up CVIs of VMT eyes were statistically similar (p = 0.72, p = 0.32 and p = 0.79 respectively).Spontaneous detachment patients' CVIs showed a 0.57±5.81% increase, vitreoretinal surgery group had a reduction of 1.098±4.76%, and the pneumatic vitreolysis patients showed a CVI reduction of 0.307±4.24%. However, none of these changes was found to be statistically significant when compared between the groups (p = 0.21, r = 0.02).

DISCUSSION

Previous studies have argued that vitreomacular traction might have a role on the choroidal changes seen in the vitreoretinal interface disorders. This study has shown that VMT alone does not cause any significant changes in choroidal vascular index pre or post traction release.

Distribution of Neurofilament in Peeled Internal Limiting Membrane

BACKGROUND AND OBJECTIVE

The aim was to study the distribution of neurofilament in peeled internal limiting membrane (ILM).

PATIENTS AND METHODS

Prospective case study. Vitrectomy and ILM peeling were performed in patients with epiretinal membrane and macular hole. ILM flap specimens were obtained as one disc area size from five locations. Immunofluorescent staining was performed with an antineurofilament heavy antibody. Using a confocal microscope, retinal cell debris density was studied using the ImageJ program.

RESULTS

Percent of stained neurofilament was 1.58 ± 1.14% in total (2.45 ± 1.37% in extranasal, 1.97 ± 0.75% in extratemporal, 1.93 ± 1.26% in juxta-nasal, 0.89 ± 0.69% in fovea, and 0.63 ± 0.46% in juxtatemporal). The Kruskal-Wallis test revealed significant differences among groups (P < 0.05). Bonferroni post hoc analysis only confirmed significant difference between juxtatemporal and extranasal groups (P < 0.05).

CONCLUSIONS

In peeled ILM flap, neurofilaments are rarely detected in the juxtatemporal area. However, they are frequently detected in the extranasal area. [Ophthalmic Surg Lasers Imaging Retina 2023;54:643-648.].

Effect of Air Tamponade among Patients with Epiretinal Membranes and Intraretinal Cystoid Changes Undergoing Vitrectomy with Membrane Peeling - A Prospective Randomized Trial

BACKGROUND

The effect of air tamponade among patients undergoing vitrectomy with membrane peeling for removal of epiretinal membranes (ERM) is controversially discussed. The aim of the present study was to analyze differences in outcomes between air tamponade and balanced salt solution (BSS) in a study population with preoperative intraretinal cystoid changes.

PATIENTS AND METHODS

This randomized study included patients scheduled for pars plana vitrectomy with membrane peeling owing to ERM and intraretinal cystoid changes. Air tamponade or BSS at the end of surgery was applied according to preoperative randomization. Optical coherence tomography and best-corrected distance visual acuity (DCVA) measurements were performed before surgery, 5 days after surgery, and 3 months after surgery.

RESULTS

From 96 patients included, 85 eyes had full follow-up and could be included for analysis. Median improvement of DCVA was + 16 EDTRS letters (IQR: 8 to 22) among patients with BSS, while it was + 13 EDTRS letters (IQR: 8 to 17) among patients with air tamponade. There was a trend for better improvement of DCVA when BSS was left at the end of surgery, compared to air tamponade, but not reaching statistical significance.

CONCLUSIONS

There were no statistically significant differences concerning resorption of preoperative intraretinal cystoid changes, improvement of visual acuity, and final DVCA between air tamponade and BSS.

Diagnostic Reliability of Optical Coherence Tomography Biomarkers for Postsurgical Success in Visual Acuity in Patients with Idiopathic Epiretinal Membranes

INTRODUCTION

Several optical coherence tomography (OCT) biomarkers for postsurgical success in patients with idiopathic epiretinal membranes (iERMs) have been described in single predictor analyses. The aim of this study was to assess the reliability of diagnosis of OCT biomarkers and to calculate their impact on postsurgical visual acuity by applying multiple regression analysis.

METHODS

This retrospective study included patients scheduled for pars plana vitrectomy with membrane peeling for iERMs. Presurgical OCT scans were analyzed for the presence of OCT biomarkers by two reviewers. Intra- and interobserver reliability was calculated with the Kuder-Richardson 20 test.

RESULTS

Among the 136 patients included, intra-/interobserver reliability of the OCT biomarkers was 0.89/0.70 for ectopic inner foveal layer (EIFL), 0.82/0.53 for disorganization of retinal inner layer (DRIL), 0.93/0.89 for intraretinal cystoid changes, 0.84/0.78 for alterations of the ellipsoid zone, 0.84/0.72 for cotton ball sign, 0.68/0.58 for hyperreflective foci, 0.55/0.47 for epimacular membrane rips (EMM-rips), and 0.87/0.60 for retinal contraction. Only DRIL and central subfield macular thickness (CMT) were significant predictors for BCVA 3 months after surgery in a multiple regression analysis.

CONCLUSION

Intraobserver reliability of OCT biomarkers was higher than interobserver reliability, reflecting both clinical and grading experience with respect to OCT biomarker evaluation. DRIL and CMT were shown to be significant predictors in a multiple regression analysis, with potential for negative influence on final BCVA after vitrectomy with membrane peeling for iERMs.

Blood inflammatory biomarkers in participants with idiopathic epiretinal membrane: A retrospective case series study

The objective was to evaluate the levels of monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in patients with idiopathic epiretinal membrane (iERM). This retrospective case series study comprised of participants with iERM and participants with cataract. The values of MLR, NLR, PLR and from participants' peripheral blood were assessed among groups. The best cutoff value of MLR, NLR, and PLR in iERM was found by performing a receiver operating characteristic curve analysis and determining the optimum cutoff value for each variable. In total, 95 participants with iERM were included in the study group, and 61 participants with senile cataract were included as controls. The lymphocyte count in the iERM group was significantly lower than the control group (1.69 ± 0.63 vs. 1.95 ± 0.53, P = .003). The monocyte count in the iERM group was significantly higher than the control group (0.39 ± 0.11 vs. 0.31 ± 0.10, P < .001). The area under the curve of MLR, NLR, and PLR in differentiating patients with IERM and controls was 0.782, 0.645, and 0.657, respectively, according to receiver operating characteristic. The best cutoff value of MLR was > 0.18, with sensitivity and specificity of 74.7% and 75.4%, respectively. The NLR was > 2.06, with a sensitivity and specificity of 50.5% and 83.6%, respectively. The PLR was > 95.89, with a sensitivity and specificity of 86.3% and 41.0%, respectively. The findings of this study suggest that systemic inflammation may be associated with iERM. IERM patients may be prone to have high MLR, NLR, and PLR values.

Co-Expression of Podoplanin and CD44 in Proliferative Vitreoretinopathy Epiretinal Membranes

Epiretinal membranes (ERMs) are sheets of tissue that pathologically develop in the vitreoretinal interface leading to progressive vision loss. They are formed by different cell types and by an exuberant deposition of extracellular matrix proteins. Recently, we reviewed ERMs' extracellular matrix components to better understand molecular dysfunctions that trigger and fuel the onset and development of this disease. The bioinformatics approach we applied delineated a comprehensive overview on this fibrocellular tissue and on critical proteins that could really impact ERM physiopathology. Our interactomic analysis proposed the hyaluronic-acid-receptor cluster of differentiation 44 (CD44) as a central regulator of ERM aberrant dynamics and progression. Interestingly, the interaction between CD44 and podoplanin (PDPN) was shown to promote directional migration in epithelial cells. PDPN is a glycoprotein overexpressed in various cancers and a growing body of evidence indicates its relevant function in several fibrotic and inflammatory pathologies. The binding of PDPN to partner proteins and/or its ligand results in the modulation of signaling pathways regulating proliferation, contractility, migration, epithelial-mesenchymal transition, and extracellular matrix remodeling, all processes that are vital in ERM formation. In this context, the understanding of the PDPN role can help to modulate signaling during fibrosis, hence opening a new line of therapy.

Profiling of idiopathic macular hole vitreous proteome identifies the role of extracellular matrix remodelling, epithelial-mesenchymal transformation and unfolded protein-response pathways

Purpose

To analyze and describe the proteome of the vitreous humour in eyes with idiopathic macular holes.

Methods

We performed mass spectrometry (MS)-based label-free quantitative analysis of the vitreous proteome of idiopathic macular hole (IMH) and control donor vitreous. Comparative quantification was performed using SCAFFOLD software which calculated fold changes of differential expression. Bioinformatics analysis was performed using DAVID and STRING software.

Results

A total of 448 proteins were identified by LC-MS/MS in IMH and cadaveric eye vitreous samples, of which 199 proteins were common. IMH samples had 189 proteins that were unique and 60 proteins were present only in the control cadaveric vitreous. We found upregulation of several extracellular matrix (ECM) and cytoskeletal proteins, namely collagen alpha-1 (XVIII) chain, N-cadherin, EFEMP1/fibulin-3, basement membrane-specific heparan sulfate proteoglycan core protein, and target of Nesh-3. Several cytoskeleton proteins, namely tubulin, actin, and fibronectin levels, were significantly lower in IMH vitreous, probably reflecting increased ECM degradation. IMH vitreous also had a downregulation of unfolded protein response-mediated-mediated apoptosis proteins, possibly related to a state of increased cell survival and proliferation, along with a remodelling and aberrant production of ECM contents.

Conclusion

The pathogenesis of macular holes may involve ECM remodelling, epithelial-mesenchymal transformation, downregulation of apoptosis, protein folding defects, and complement pathway. The vitreo-retinal milieu in macular holes contain molecules related to both ECM degradation and inhibition of the same, thereby maintaining a homeostasis.

MicroRNA-494 augments fibrotic transformation of human retinal pigment epithelial cells and targets p27 with cell-type specificity

Epiretinal membranes (ERMs) are the result of fibro-cellular proliferation that cause distortion and impairment of central vision. We hypothesized that select microRNAs (miRs) regulate retinal fibro-proliferation and ERM formation. Following IRB approval, a pilot study was performed in patients presenting for retina surgery with and without clinical ERMs. Total RNA was isolated from ERM tissue and controls from non-ERM vitreous and subjected to miR profiling via microarray analysis. MiR-494 was identified as the only miR selectively expressed at significantly greater levels, and in silico analysis identified p27 as a putative fibroproliferative gene target of miR-494. In vitro testing of miR-494 and p27 in fibrotic transformation was assessed in spontaneously immortalized human retinal pigment epithelial (RPE) and human Müller cell lines, stimulated to transform into a fibroproliferative state via transforming growth factor beta (TGFβ). Fibroproliferative transformation was characterized by de novo cellular expression of alpha smooth muscle actin (αSMA). In both RPE and Müller cells, both TGFβ and miR-494 mimic decreased p27 expression. In parallel experiments, transfection with p27 siRNA augmented TGFβ-induced αSMA expression, while only in RPE cells did co-transfection with miR-494 inhibitor decrease αSMA levels. These results demonstrate that miR-494 augments fibrotic transformation in both Müller cells and RPEs, however only in RPEs does miR-494 mediate fibrotic transformation via p27. As p27 is known to regulate cellular proliferation and differentiation, future studies should extend clinical testing of miR-494 and/or p27 as a potential novel non-surgical therapy for ERMs, as well as identify relevant miR-494 targets in Müller cells.

The G-Protein-Coupled Formyl Peptide Receptor 2 Promotes Endothelial-Mesenchymal Transition in Diabetic Retinopathy

INTRODUCTION

In proliferative diabetic retinopathy (PDR), retinal neovascularization is the essential pathogenic process that is linked to endothelial-to-mesenchymal transition (EndoMT) induced by high glucose (HG). This pathophysiological process may be regulated by a G-protein-coupled chemoattractant receptor FPR2 (mouse Fpr2), involved in inflammatory cell migration and proliferation. In the current study, we investigated the role of Fpr2 in regulating EndoMT and the underlying mechanisms during diabetic retinopathy progression.

METHODS

FPR2 agonist or inhibitor was added to human microvascular endothelial cells (HMECs) exposed to normal glucose or HG. Morphologic, phenotypic, and functional changes of HMECs as well as the formation of microvasculature related to EndoMT were assessed. EndoMT biomarkers were detected in the retinal tissues of diabetic mice and fibrovascular epiretinal membranes (FVMs) from patients with PDR.

RESULTS

HG upregulated FPR2 in HMECs, which triggered morphological changes, and the cells acquired mesenchymal phenotype, with enhanced cell migration, viability, and angiogenic process shown by tube formation and aortic ring sprouting. Inhibition of FPR2 attenuated HG-induced EndoMT and endothelial cell migration to form vessel-like tube structures. RNA sequence and protein analysis further revealed that inhibition of FPR2 decreased the expression of genes associated with EndoMT. ERK1/2 and P38 signaling pathway was activated in HMECs, promoting neovascularization in HG-induced EndoMT of HMECs. In vivo, increased expression of mesenchymal markers was detected in the retina of diabetic mice and FVMs from patients with PDR. FPR2 deficiency was associated with diminished EndoMT-related phenotypic changes in the retina of diabetic mice.

CONCLUSIONS

FPR2 is actively involved in the progression of EndoMT that may contribute to the pathogenesis of PDR. Thus, FPR2 may be a potential therapeutic target for PDR.

Proteomics and phosphoproteomics analysis of vitreous in idiopathic epiretinal membrane patients

PURPOSE

The purpose of the present study was to characterize the idiopathic epiretinal membrane (iERM) through proteomics and phosphoproteomics analysis to facilitate the diagnosis and treatment of iERM.

EXPERIMENTAL DESIGN

The vitreous of 25 patients with an iERM and 15 patients with an idiopathic macular hole were analyzed by proteomic and phosphoproteomic analysis based on tandem mass tag. PRM was used to verify the differential proteins.

RESULTS

Proteomic analysis identified a total of 878 proteins, including 50 differential proteins. Tenascin-C, galectin-3-binding protein, glucose-6-phosphate isomerase, neuroserpin, collagen alpha-1(XI) chain, and collagen alpha-1(II) chain were verified to be upregulated in iERM by PRM. Phosphoproteomic analysis identified a total of 401 phosphorylation sites on 213 proteins, including 27 differential phosphorylation sites on 24 proteins. Mitogen-activated protein kinase-activated protein kinase (MAPKAPK)3 and MAPKAPK5 were predicted as the major kinases in the vitreous of iERM. Twenty-six of the differential proteins and phosphorylated proteins may be closely related to fibrosis in iERM.

CONCLUSION AND CLINICAL RELEVANCE

Our results indicated the potential biomarkers or therapeutic targets for iERM, provided key kinases that may be involved in iERM. Fibrosis plays an essential role in iERM, and further exploration of related differential proteins has important clinical significance.

Untangling the Extracellular Matrix of Idiopathic Epiretinal Membrane: A Path Winding among Structure, Interactomics and Translational Medicine

Idiopathic epiretinal membranes (iERMs) are fibrocellular sheets of tissue that develop at the vitreoretinal interface. The iERMs consist of cells and an extracellular matrix (ECM) formed by a complex array of structural proteins and a large number of proteins that regulate cell–matrix interaction, matrix deposition and remodelling. Many components of the ECM tend to produce a layered pattern that can influence the tractional properties of the membranes. We applied a bioinformatics approach on a list of proteins previously identified with an MS-based proteomic analysis on samples of iERM to report the interactome of some key proteins. The performed pathway analysis highlights interactions occurring among ECM molecules, their cell receptors and intra- or extracellular proteins that may play a role in matrix biology in this special context. In particular, integrin β1, cathepsin B, epidermal growth factor receptor, protein-glutamine gamma-glutamyltransferase 2 and prolow-density lipoprotein receptor-related protein 1 are key hubs in the outlined protein–protein cross-talks. A section on the biomarkers that can be found in the vitreous humor of patients affected by iERM and that can modulate matrix deposition is also presented. Finally, translational medicine in iERM treatment has been summed up taking stock of the techniques that have been proposed for pharmacologic vitreolysis.

Characterization of Macrophage-Like Cells in Retinal Vein Occlusion Using En Face Optical Coherence Tomography

Purpose

To investigate the clinical features of a macrophage-like cell (MLC) obtained by en face optical coherence tomography (OCT) in retinal vein occlusion (RVO).

Methods

The study involved 36 patients with treatment-naïve unilateral acute RVO, including 21 branch RVO (BRVO) and 15 central RVO. Vessel density and macular thickness were quantified using OCT angiography. A 3-μm en face OCT slab on the inner limiting membrane in the optic nerve head (ONH) region or macular region was used to visualize the MLCs. The MLCs were binarized and quantified using a semiautomated method. The unaffected fellow eyes served as the control group.

Results

The morphology of MLCs appeared larger and plumper in RVO eyes. The mean MLC density in the ONH and macular regions was 2.46 times and 2.86 times higher than their fellow eyes, respectively (p < 0.001). The macular MLC density of the occlusive region was significantly lower than that of the unaffected region in BRVO (p = 0.01). The ONH and macular MLC densities in the non-perfused region were significantly lower than those in the perfused region in all RVO eyes (p < 0.001). The ONH MLC density in RVO eyes was negatively correlated with radial peripapillary capillary vessel density (r = -0.413, p = 0.012). Both ONH and macular MLC densities were positively correlated with macular thickness (r = 0.505, p = 0.002; r = 0.385, p = 0.02, respectively).

Conclusion

The increased density and changes of morphology characterized by OCT may indicate generalized activation and aggregation of MLCs in RVO. More MLCs are recruited in the perfused region rather than the non-perfused region. RVO eyes with a higher density of MLCs tend to suffer from the thicker macula.

The MDM2 Single-Nucleotide Polymorphism T309G Is Associated With the Development of Epimacular Membranes

Purpose: To investigate the role of the mouse double minute 2 (MDM2) gene single-nucleotide polymorphism (SNP) T309G in the development of epimacular membranes (EMMs) by analyzing the genotype distribution and consistency of the polymorphism in paired membrane-blood samples.

Methods: This was a cross–sectional genetic association study of patients with proliferative vitreoretinopathy (PVR) or EMMs. PVR membranes (PVRMs), internal limiting membranes (ILMs) (PVR-ILMs) and blood samples (PVR-blood) from patients with PVR, and EMMs, EMM-ILMs and EMM-blood from patients with EMMs were collected. The genotype of all samples was determined by Sanger sequencing. Sex composition, mean age, the genotype distribution of MDM2 T309G, the allelic frequency of the MDM2 SNP309 G allele (% G) and the somatic mutation rate at the MDM2 T309G locus (% M) were analyzed and compared. The PVR and healthy Chinese donor groups were used as controls for different comparisons.

Results: The EMM group of 62 patients was older than the PVR group of 61 patients by an average of 8.87 years (p < 0.0001), but the two groups were statistically similar in the sex composition (p = 0.1754). Importantly, G allele carriers were at a higher risk of developing EMMs than non-G allele carriers (p = 0.0479; OR = 2.047). Moreover, EMM-blood exhibited a significantly higher % G than blood samples from healthy Chinese donors (EMM-blood: 56.78%, donors: 45.61%; p = 0.0256; OR = 1.567). Regarding membrane-blood consistency, % M was significantly different between PVRMs and EMMs (PVRMs: 2.63%, EMMs: 21.57%; p = 0.0097; OR = 10.18) but not between different types of ILMs (PVR-ILMs: 18.18%, EMM-ILMs: 29.17%; p = 0.6855). Furthermore, EMMs (p = 0.0053; OR = 8.250) and EMM-ILMs (p = 0.0233; OR = 14.40) from patients with preoperative macular holes were more predisposed toward somatic mutations at the MDM2 T309G locus than those from patients without preoperative macular holes.

Conclusions:MDM2 T309G is associated with the development of EMMs. Herein, the MDM2 SNP309 G allele is first reported as an associated factor of EMMs in a Chinese population. In addition, EMMs and ILMs are genetically unstable at the MDM2 T309G locus, especially when complicated with preoperative macular holes.

[Regression of idiopathic epiretinal membrane-Case report and consideration of the possible mechanism]

In the presence of a symptomatic epiretinal gliosis, pars plana vitrectomy with membrane peeling to remove the membrane is usually indicated in clinical practice. According to common clinical experience, almost no independent regression of such an epiretinal membrane and thus healing of the pathology alone exists. Therefore, the unusual case of bilateral independent regression of idiopathic epiretinal gliosis and formation of a lamellar macular hole in a 73-year-old male patient is described. Considerations of the possible mechanism are presented based on the existing literature. These include separation of inflammatory versus noninflammatory membranes, possible separation of individual layers depending on the status of the posterior vitreous limiting membrane and also the possible action of proteolytic systems in the posterior vitreous region. Finally, the question arises, whether patients have to be informed about this fact before possible surgery.

Association of Microvasculature and Macular Sensitivity in Idiopathic Macular Epiretinal Membrane: Using OCT Angiography and Microperimetry

Purpose: To investigate the correlation between retinal capillary structure and macular function in patients with idiopathic epiretinal membrane (iERM) by using optical coherence tomography angiography (OCTA) and microperimetry.

Methods: This retrospective and observational study included 30 idiopathic ERM eyes of 30 consecutive patients. OCTA was performed to evaluate macular microvasculature including the superficial capillary plexus, deep capillary plexus, and foveal avascular zone. Best corrected visual acuity (BCVA) and microperimetry were measured at baseline and 3 months after surgery. Associations between macular microvasculature and visual function were assessed.

Results: Visual function including BCVA and macular sensitivity improved significantly at 3 months post-operatively (p < 0.001). At baseline, BCVA was positively correlated with foveal or parafoveal sensitivities and negatively correlated with central foveal thickness (p < 0.05). Pre-operative foveal sensitivity was significantly correlated with the vessel density of foveal or parafoveal superficial capillary plexus (p < 0.05). A multiple regression model revealed that pre-operative vessel density of foveal deep capillary plexus was an independent positive prognostic factor for post-operative BCVA (B = −0.020 ± 0.006, p = 0.006) and macular sensitivity (B = 0.200 ± 0.081, p = 0.027).

Conclusion: Integrated evaluation of iERM by using OCTA and microperimetry shows an association between microvasculature and macular sensitivity. Pre-operative vessel density of foveal deep capillary plexus assessed by OCTA may be a potentially valuable prognostic factor for iERM surgery.

Cellular components of the idiopathic epiretinal membrane

Idiopathic epiretinal membrane (iERM) is a fibrocellular proliferation on the inner surface of the retina, which leads to decreased visual acuity and even central visual loss. As iERM is associated to advanced age and posterior vitreous detachment, a higher prevalence is expected with increasing life expectancy and aging of the global population. Although various cell types of retinal and extra-retinal origin have been described in iERMs (Müller glial cells, astrocytes, hyalocytes, retinal pigment epithelium cells, myofibroblasts, and fibroblasts), myofibroblasts have a central role in collagen production and contractile activity. Thus, myofibroblast differentiation is considered a key event for the iERM formation and progression, and fibroblasts, Müller glial cells, hyalocytes, and retinal pigment epithelium have been identified as myofibroblast precursors. On the other side, the different cell types synthesize growth factors, cytokines, and extracellular matrix, which have a crucial role in ERM pathogenesis. In the present review, the major cellular components and their functions are summarized, and their possible roles in the iERM formation are discussed. By exploring in detail the cellular and molecular aspects of iERM, we seek to contribute for better understanding of this fibrotic disease and the origin of myofibroblasts, which may eventually drive to more targeted therapeutic approaches.

Risk factors for macular pucker after rhegmatogenous retinal detachment surgery

Macular pucker, also known as an epiretinal membrane, sometimes forms after surgical repair of a rhegmatogenous retinal detachment (RRD) and can decrease visual acuity and cause aniseikonia. However, few reports are evaluating the risk factors of macular pucker using multivariate analysis. To evaluate the risk factors for macular pucker after RRD surgery, 226 patients who underwent RRD surgery and were monitored for greater than 12 months (23.2 ± 6.4 months) after surgery were analyzed retrospectively. Of these cases, macular pucker developed in 26 cases. Multiple logistic regression models of 22 clinical characteristics were performed. An increased risk of macular pucker after RRD surgery was significantly associated with preoperative vitreous haemorrhage (Odds ratio (OR), 4.71; 95% CI 1.19–18.62), multiple retinal breaks (OR, 8.07; 95% CI 2.35–27.71), re-detachment (OR, 19.66; 95% CI 4.87–79.38), and retinal detachment area (OR, 12.91; 95% CI 2.34–71.19). Macular pucker was not associated with the surgical technique. Regardless of the surgical technique used, careful observation for postoperative macular pucker is needed after RRD surgery in high-risk cases. These findings can be used to improve the surgical management of patients with RRD. (183 words).

The Postoperative Course of Choroidal and Central Retinal Thickness in Epiretinal Membranes with Respect to Membrane Severity

INTRODUCTION

The aim of this study was to evaluate the relation between choroidal thickness (CT), central retinal thickness (CRT) and best-corrected visual acuity (BCVA) after surgery for idiopathic epiretinal membrane (iERM).

METHODS

Patients with 4 severity stages of iERM, who underwent vitrectomy with membrane- and internal limiting membrane peeling, were included in this prospective study. CRT, CT, and BCVA were assessed at baseline (BSL), 1 week, 1 and 3 months postoperatively.

RESULTS

Twenty-one eyes were phakic, 11 eyes pseudophakic at BSL, in 14 cases combined cataract surgery was performed. BCVA was highest in stage 1 and 2, lowest in stage 4 iERM (p < 0.001) and correlated with CRT. After surgery, CRT decreased and BCVA increased significantly (p < 0.05). CT did not show significant differences among stages (p = 0.23). BSL CRT did not differ between phakic and pseudophakic eyes, the least reduction after surgery was detected in patients who underwent combined cataract surgery and vitrectomy. BSL CT was greater in phakic than in pseudophakic eyes (p = 0.033). Postoperative CT decreased in pseudophakic and phakic eyes, but remained higher after combined surgery (p = 0.0048).

CONCLUSION

CT is not related to the severity of iERM. Choroidal changes did not influence the BCVA. Additional cataract surgery seems to cause longer recovery in CT and CRT.

Effect of Periocular Triamcinolone Acetonide on Prevention of Postsurgical Intraretinal Cystoid Changes after Vitrectomy with Membrane Peeling

BACKGROUND

Newly developed intraretinal cystoid changes after vitrectomy with membrane peeling for removal of epiretinal membranes have the potential to lead to worse postsurgical results compared to patients without. The aim of the present study was to evaluate the feasibility of additional periocular application of triamcinolone acetonide as a routine adjunct at the end of vitrectomy with membrane peeling, and to compare the presence of postsurgical intraretinal cystoid changes in the first 3 months after surgery among patients with idiopathic epiretinal membranes to a historical group of patients that did not receive triamcinolone acetonide.

PATIENTS AND METHODS

The medical records of 41 eyes of 41 patients that underwent 23 G or 25 G pars plana vitrectomy with membrane peeling for removal of epiretinal membranes and additional periocular triamcinolone acetonide application at the end of surgery were retrospectively reviewed. Optical coherence tomography findings during routine follow-ups at 3 - 5 days, 1 month, and 3 months and visual acuity at 3 months after surgery were evaluated and compared to preoperative findings. Furthermore, postsurgical intraocular pressure was assessed.

RESULTS

Periocular triamcinolone acetonide at the end of surgery was well tolerated among all patients. In total, 10% of patients had an increased intraocular pressure at least at one follow-up. Best-corrected visual acuity improved in 91% of patients with idiopathic epiretinal membranes with a mean improvement of + 3 ± 2 lines (Snellen) and was comparable to a historic group of patients (p = 0.307). Early transient macular edema could not be detected in any of the patients, while there were cases with this pathology in the historic group of patients, but neither occurrence of newly developed intraretinal cystoid changes nor macular thickness at 3 months after surgery were significantly different between patients with and without triamcinolone acetonide (p = 0.385 and p = 0.879).

CONCLUSIONS

Periocularly applied triamcinolone acetonide at the end of vitrectomy with membrane peeling was well tolerated and showed prevention of early transient macular edema but did not prevent the development of new postoperative intraretinal cystoid changes.

Müller cells and astrocytes in tractional macular disorders

Tractional deformations of the fovea mainly arise from an anomalous posterior vitreous detachment and contraction of epiretinal membranes, and also occur in eyes with cystoid macular edema or high myopia. Traction to the fovea may cause partial- and full-thickness macular defects. Partial-thickness defects are foveal pseudocysts, macular pseudoholes, and tractional, degenerative, and outer lamellar holes. The morphology of the foveal defects can be partly explained by the shape of Müller cells and the location of tissue layer interfaces of low mechanical stability. Because Müller cells and astrocytes provide the structural scaffold of the fovea, they are active players in mediating tractional alterations of the fovea, in protecting the fovea from such alterations, and in the regeneration of the foveal structure. Tractional and degenerative lamellar holes are characterized by a disruption of the Müller cell cone in the foveola. After detachment or disruption of the cone, Müller cells of the foveal walls support the structural stability of the foveal center. After tractional elevation of the inner layers of the foveal walls, possibly resulting in foveoschisis, Müller cells transmit tractional forces from the inner to the outer retina leading to central photoreceptor layer defects and a detachment of the neuroretina from the retinal pigment epithelium. This mechanism plays a role in the widening of outer lameller and full-thickness macular holes, and contributes to visual impairment in eyes with macular disorders caused by conractile epiretinal membranes. Müller cells of the foveal walls may seal holes in the outer fovea and mediate the regeneration of the fovea after closure of full-thickness holes. The latter is mediated by the formation of temporary glial scars whereas persistent glial scars impede regular foveal regeneration. Further research is required to improve our understanding of the roles of glial cells in the pathogenesis and healing of tractional macular disorders.

Vitreous from idiopathic epiretinal membrane patients induces glial-to-mesenchymal transition in Müller cells

Idiopathic epiretinal membranes (ERMs) are fibrocellular membranes containing extracellular matrix proteins and epiretinal cells of retinal and extraretinal origin. iERMs lead to decreased visual acuity and their pathogenesis has not been completely defined. Macroglial Müller cells appear to play a pivotal role in the pathogenesis of iERM where they may undergo glial-to-mesenchymal transition (GMT), a transdifferentiation process characterized by the downregulation of Müller cell markers, paralleled by the upregulation of pro-fibrotic myofibroblast markers. Previous observations from our laboratory allowed the molecular identification of two major clusters of iERM patients (named iERM-A and iERM-B), iERM-A patients being characterized by less severe clinical features and a more "quiescent" iERM gene expression profile when compared to iERM-B patients. In the present work, Müller MIO-M1 cells were exposed to vitreous samples obtained before membrane peeling from the same cohort of iERM-A and iERM-B patients. The results demonstrate that iERM vitreous induces proliferation, migration, and GMT in MIO-M1 cells, a phenotype consistent with Müller cell behavior during iERM progression. However, even though the vitreous samples obtained from iERM-A patients were able to induce a complete GMT in MIO-M1 cells, iERM-B samples caused only a partial GMT, characterized by the downregulation of Müller cell markers in the absence of upregulation of pro-fibrotic myofibroblast markers. Together, the results indicate that a relationship may exist among the ability of iERM vitreous to modulate GMT in Müller cells, the molecular profile of the corresponding iERMs, and the clinical features of iERM patients.

Morphological alternation and influence of aqueous flare in idiopathic epiretinal membrane

Background

Idiopathic epiretinal membrane (iERM) is a common retinal disease in the elderly population. The exact pathogenesis of iERM is unknown. The present study aimed to evaluate the relationship between aqueous flare and morphology of iERM using swept-source optical coherence tomography (OCT).

Methods

A consecutive series of 36 eyes of 33 patients with iERM and 109 control eyes of 109 patients were retrospectively examined. Aqueous flare measurements and OCT images were obtained on the same day. The average total retinal, inner retinal, outer retinal, and choroidal thicknesses were calculated using the thickness map mode with an Early Treatment Diabetic Retinopathy Study nine-zone grid that was divided into three zones. The maximum depth of the retinal folds in iERMs was manually measured. The correlation among flare value, maximum depth of folds, and retinal and choroidal thicknesses was evaluated. The morphological changes between the control eyes and the eyes with iERM in different stages were examined.

Results

The result demonstrated a significant positive correlation between the aqueous flare value and total and inner retinal thicknesses in the early stage of iERM. There was a significant positive correlation between the maximum depth of folds and total and inner retinal thicknesses in the early stage of iERM, and the maximum depth of folds significantly increased in the advanced stage. The total and inner retinal thicknesses and proportion of inner retinal thickness significantly increased as the stage of iERM progressed.

Conclusions

The aqueous flare value was associated with retinal thickness in the early stage of iERM, which supports the idea that inflammation or breakdown of blood–ocular barrier is involved in the process of iERM formation. The maximum retinal folds increased as the stage of iERM progressed and retinal thickness increased, which indicates that the tangential force increases as the iERM stage progresses.

Vitreomacular disorders: a review of the classification, pathogenesis and treatment paradigms including new surgical techniques

This review explores how optical coherence tomography has guided our assessment of vitreomacular disorders. Vitreomacular disorders (VMD), such as macular holes and epiretinal membranes are common and potentially sight threatening. The introduction and widespread use of optical coherence tomography (OCT) imaging technology has transformed our ability to visualise the vitreoretinal interface. This review discusses the pathogenesis and updated classification scheme for VMD in the OCT era. Imaging biomarkers and the treatment algorithm, including the role of novel therapeutics, for managing patients with VMD are presented.

Prevalence and Risk Factors of Epiretinal Membranes in a Chinese Population: The Kailuan Eye Study

Purpose

To investigate the prevalence of epiretinal membranes (ERMs) and their risk factors in a Chinese population.

Methods

The community-based Kailuan Eye Study included 14,440 participants (9835 male, 4605 female) with a mean age of 54.0 ± 13.3 years (range, 20-110 years). They underwent a systemic and ophthalmologic examination. ERMs were diagnosed on fundus photographs.

Results

Retinal photographs assessable for the presence of ERMs were available for 13,295 (92.0%) individuals (9094 male) with a mean age of 53.6 ± 13.3 years (range, 20-110 years). ERMs were found in 1013 participants (1489 eyes) with a prevalence of 7.6% (95% confidence interval [CI], 7.1%-8.1%). Secondary ERMs caused by intraocular reasons were found 46 (4.5%) individuals (69 [4.6%] eyes). A higher prevalence of any ERMs (and of primary ERMs) was associated with older age (odds ratio [OR]: 1.08; 95% CI:1.07-1.10), higher body mass index (OR: 1.05; 95% CI: 1.00-1.11), higher prevalence of smoking (OR:1.43; 95% CI: 1.01-2.03), higher serum concentration of glucose (OR: 1.08; 95% CI: 1.04-1.13), and lower serum concentration of uric acid (OR: 0.99; 95% CI: 0.99-1.00). Visual acuity was significantly (P = 0.002) lower in eyes with premacular fibroses than in eyes with cellophane macular reflexes.

Conclusions

In our cross-sectional community-based study, the prevalence of all ERMs was 7.6%. Among the group of participants with ERMs, secondary ERMs caused by intraocular reasons were detected in 46 (4.5%) individuals (69 [4.6%] eyes). A higher prevalence of any ERM and of primary ERMs was associated with older age, higher body mass index, higher prevalence of smoking, a higher serum concentration of glucose, and a lower serum concentration of uric acid.

The extracellular matrix complexity of idiopathic epiretinal membranes and the bilaminar arrangement of the associated internal limiting membrane in the posterior retina

PURPOSE

To study the composition of the internal limiting membrane (ILM) of the retina, the extracellular matrix (ECM) of idiopathic epiretinal membranes (iERMs), and the relationships occurring between the two membranes.

METHODS

Forty-six iERMs, 24 of them associated with the ILM, were collected and included in this study. The investigation has been carried out by immunofluorescence and confocal microscopy on glutaraldehyde- and osmium-fixed epon-embedded samples and on frozen samples. Sections were double or triple labelled with antibodies against vimentin; collagens I, III, IV, α5(IV), and VI; laminin 1 + 2; laminin α2-, α4-, α5-, β1-, β2-, β3-, γ1-, and γ2-chains; entactin; and fibronectin.

RESULTS

iERM thickness was not uniform. Almost 14% of iERMs showed thickenings due to folding of their ECM component under the cell layer. The vitreal side of iERMs was often shorter than the attached ILM. In this case, the ILM resulted folded under the iERM. ILMs contained laminin 111; laminin α2-, α5-, β1-, β2-, and γ1-chains; entactin; collagens I; α5(IV); [α1(IV)]₂α2(IV); and VI. Laminins, entactin, and α5(IV) were gathered on the retinal half of the ILM, whereas collagens [α1(IV)]₂α2(IV) and I were restricted to the vitreal side. Collagen VI was detected on both sides of the ILM. iERMs expressed laminin 111, collagens III, [α1(IV)]₂α2(IV) and VI, entactin, and fibronectin. Entactin co-localized with laminins and collagen IV.

CONCLUSIONS

Analysis of laminins and collagen chain expression indicates that ILM contains laminin 111 (former laminin 1), laminin 521 (former laminin 11), laminin 211 (former laminin 2), collagen [α1(IV)]₂α2(IV), and collagen α3(IV)α4(IV)α5. In contrast, iERMs express only collagen [α1(IV)]₂α2(IV) and laminin 111. In addition, both iERMs and ILMs contain entactin. The presence of three major constituents of the basement membranes co-localized together in iERMs is suggestive for a deranged process of basement membrane formation which fails to assemble properly. In view of the many interactions occurring among its proteins, the ECM of either the iERMs or the ILMs can account for their reciprocal adhesiveness. In addition, the peculiar deposition of the ECM observed in some samples of iERM is suggestive for its involvement in the formation of macular puckers.

Epiretinal membrane: A review

The prevalence of epiretinal membrane (ERM) is 7% to 11.8%, with increasing age being the most important risk factor. Although most ERM is idiopathic, common secondary causes include cataract surgery, retinal vascular disease, uveitis and retinal tears. The myofibroblastic pre-retinal cells are thought to transdifferentiate from glial and retinal pigment epithelial cells that reach the retinal surface via defects in the internal limiting membrane (ILM) or from the vitreous cavity. Grading schemes have evolved from clinical signs to ocular coherence tomography (OCT) based classification with associated features such as the cotton ball sign. Features predictive of better prognosis include absence of ectopic inner foveal layers, cystoid macular oedema, acquired vitelliform lesions and ellipsoid and cone outer segment termination defects. OCT-angiography shows reduced size of the foveal avascular zone. Vitrectomy with membrane peeling remains the mainstay of treatment for symptomatic ERMs. Additional ILM peeling reduces recurrence but is associated with anatomical changes including inner retinal dimpling.

Comparison of Anatomical and Functional Results of Surgeries Performed with Nitinol Flex Loop or Forceps in Primary Epiretinal Membrane

Purpose: To compare surgery's effect with nitinol flex loop (NFL) or forceps on retinal layers and functional outcomes in the primary epiretinal membrane (ERM).Methods: The operations were classified according to the use of the NFL or forceps. Automatic segmentation of the individual inner retinal layers was performed by spectral-domain optical coherence tomography software, and best-corrected visual acuity (BCVA) before surgery and at the last follow-up visit postoperatively were compared.Results: Forty-two eyes of 42 patients were included with a mean age of 66.9 ± 5.7 years. 45.2% of the surgeries were NFL assisted, 54.8% were forceps assisted. The mean follow-up duration was 9.8 ± 1.3 months. The mean BCVA was 0.79 ± 0.42 vs 0.77 ± 0.39 logMAR in the preoperative period and 0.42 ± 0.27 vs. 0.40 ± 0.21 logMAR at last follow-up in the NFL vs forceps group respectively (p= .403). The retinal nerve fiber layer (RNFL)(32.5% vs. 50.1%, p= .009), ganglion cell layer (18.1% vs. 41.4%, p= .021), inner plexiform layer (13.5% vs. 32.7%, p= .031) and inner nuclear layer (15.5% vs. 30.3%, p= .011) thickness decreased significantly more in the forceps group. The mean surgical time was not significantly different (45.2 ± 5.1 vs. 51.1 ± 6.1 minutes) in the NFL vs. forceps groups, respectively (p= .331).Conclusion: Following primary ERM surgery, the inner retinal layers become thinner; RNFL impacted the most, which was found higher in forceps assisted surgeries. This result shows that the NFL can be used safely in macular surgery.

Immunology and Pathology in Ocular Drug Development

Clear vision is dependent on features that protect the anatomical integrity of the eye (cornea and sclera) and those that contribute to internal ocular homeostasis by conferring hemangiogenic (avascular tissues and antiangiogenic factors), lymphangiogenic (lack of draining lymphatics), and immunologic (tight junctions that form blood-ocular barriers, immunosuppressive cells, and modulators) privileges. The later examples are necessary components that enable the eye to maintain an immunosuppressive environment that responds to foreign invaders in a deviated manner, minimizing destructive inflammation that would impair vision. These conditions allowed for the observations made by Medawar, in 1948, of delayed rejection of allogenic tissue grafts in the anterior chamber of mouse eye and permit the sequestration of foreign invaders (eg, Toxoplasma gondii) within the retina of healthy individuals. Yet successful development of intraocular drugs (biologics and delivery devices) has been stymied by adverse ocular pathology, much of which is driven by immune pathways. The eye can be intolerant of foreign protein irrespective of delivery route, and endogenous ocular cells have remarkable plasticity when recruited to preserve visual function. This article provides a review of current understanding of ocular immunology and the potential role of immune mechanisms in pathology observed with intraocular drug delivery.

[Proliferative vitreoretinopathy (PVR) minimal: same, same but different. Characteristics and surgical treatment of PVR-associated macular pucker]

BACKGROUND

Epiretinal membrane formation resulting in a macular pucker is among the typical complications associated with proliferative vitreoretinopathy (PVR) in retinal detachment and has a major impact on the functional outcome after surgical treatment.

METHODS

A literature search was carried out in PubMed.

RESULTS

Approaches to the surgical treatment of PVR-associated macular pucker include complete membrane removal within the vascular arcades aimed at relieving retinal traction at the posterior pole and peeling of the internal limiting membrane (ILM). As a further option it has been suggested that primary ILM peeling in rhegmatogenous retinal detachment repair may reduce or even prevent postoperative epiretinal membrane formation. In addition, correct timing of surgery is a factor that may contribute to successful treatment.

DISCUSSION

Due to the particularly strong adhesion and the frequent occurrence of concurrent retinal detachment, the surgical approach to PVR-associated macular pucker is particularly challenging. As with idiopathic epiretinal membranes, surgical removal has the potential to improve functional outcomes; however, visual improvement depends largely on whether the macula was involved in the original retinal detachment.

Heat Shock Protein 90 Involvement in the Development of Idiopathic Epiretinal Membranes

Purpose

This work was aimed to further characterize cells of idiopathic epiretinal membranes (iERMs). We wanted to determine the contribution of 90-kDa heat shock protein (HSP90) to sustain the transforming growth factor-β (TGF-β)-mediated signal transduction pathway in iERM.

Methods

Immunofluorescence and confocal microscopy were carried out on deplasticized sections from 36 epiretinal membranes processed for electron microscopy and on frozen sections from five additional samples with antibodies against α-smooth muscle actin (αSMA), vimentin, glial fibrillary acidic protein (GFAP), SMAD2, HSP90α, type-II TGF-β1 receptor (TβRII), type-I collagen, and type-IV collagen. In addition, Müller MIO-M1 cells were transfected with HSP90 and challenged with TGF-β1.

Results

Double and triple labeling experiments showed that a variable number of TβRII+ cells were present in 94.1% of tested iERMs and they were mostly GFAP-/αSMA+/vimentin+/HSP90α+. In almost half of the cases these cells contained type-I collagen, suggesting their involvement in matrix deposition. HSP90 overexpressing MIO-M1 cells challenged with TGF-β1 showed increased levels of TβRII, SMAD2, SMAD3, and phosphor-SMAD2. Nuclear SMAD2 staining could be observed in HSP90α+ cells on frozen sections of iERMs.

Conclusions

Cells in iERMs that express TβRII are also HSP90α+ and show the antigenic profile of myofibroblast-like cells as they are GFAP-/αSMA+/vimentin+. HSP90α-overexpressing MIO-M1 cells challenged with TGF-β1 showed an increased activation of the SMAD pathway implying that HSP90α might play a role in sustaining the TGF-β1-induced fibrotic response of iERM cells.

QUANTITATIVE ASSESSMENT OF THE FOVEAL AVASCULAR ZONE USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY BEFORE AND AFTER SURGERY FOR IDIOPATHIC EPIRETINAL MEMBRANE

PURPOSE

To investigate, using optical coherence tomography angiography, the foveal avascular zone (FAZar), the FAZ perimeter (FAZp), the acircularity index of the FAZ (FAZai), and the density of vessels surrounding the FAZ (FAZvd) before and after idiopathic epiretinal membrane surgery, and associations of these parameters with postoperative best-corrected visual acuity, letter score gain, and central foveal thickness.

METHODS

We retrospectively reviewed preoperative and postoperative (sixth month) medical records of 28 eyes of 28 patients who undergone epiretinal membrane surgery and had an intact ellipsoid zone.

RESULTS

There were significant increases in best-corrected visual acuity, FAZar, and FAZp and decreases in central foveal thickness and FAZai (all P < 0.05). Postoperative best-corrected visual acuity was not significantly correlated with any preoperative parameters. Postoperative letter score gain and central foveal thickness correlated negatively with preoperative FAZar and preoperative FAZp (all P < 0.05). Multivariable linear regression analysis revealed that preoperative FAZp was independently associated with postoperative letter score gain (P < 0.05).

CONCLUSION

The FAZ enlarges and becomes more circular after epiretinal membrane surgery. Postoperative best-corrected visual acuity is not associated with any FAZ parameters. In eyes with an intact foveal ellipsoid zone, especially a smaller preoperative FAZp is associated with more postoperative letter score gain.

Intraretinal microvascular changes after ERM and ILM peeling using SSOCTA

BACKGROUND

To prospectively investigate retinal vascular changes in patients undergoing epiretinal membrane (ERM) and internal limiting membrane (ILM) peeling using swept source optical coherence tomography angiography (SSOCTA).

METHODS

Consecutive patients were grouped based on ERM severity and followed using SSOCTA up to month 3 after surgical intervention. Superficial and deep foveal avascular zone (s/dFAZ) as well as foveal and parafoveal vessel density (VD) were correlated with ERM severity and visual acuity. Differences between groups were evaluated.

RESULTS

Significant correlations were found between ERM severity and baseline sFAZ, dFAZ and best corrected visual acuity (BCVA), central retinal subfield thickness (CST) and ΔCST (r = -0.52, r = -0.43, r = -0.42, r = 0.58, r = 0.39; all p<0.05). Vascular flow parameters did not correlate with age, peeling size, pseudophakia or CST, but correlated with intraretinal cysts presence. No associations of BCVA with any of the OCTA parameters across time were found. Significant differences between ERM severity groups 1 and 2 were found for sFAZ at baseline (p = 0.005) and at the 3-month follow-up (p = 0.014), and for dFAZ at baseline (p = 0.017). Superficial foveal and parafoveal VD were not significantly different between groups (all p>0.05).

CONCLUSIONS

This study clearly shows that ERM severity based on ERM staging has to be taken into account when undertaking studies in patients with idiopathic ERM using SSOCTA. Further, specific changes in the superficial and deep retinal vasculature in eyes undergoing ERM and ILM peeling were found. However, the clinical usefulness and prognostic value for post-surgical treatment BCVA of the SSOCTA-derived variables (sFAZ and dFAZ area, as well as foveal and parafoveal VD) used remains questionable.

EPIRETINAL MEMBRANE REMOVAL WITH FOVEAL-SPARING INTERNAL LIMITING MEMBRANE PEELING: A Pilot Study

PURPOSE

To compare the retinal sensitivity after complete internal limiting membrane (ILM) peeling with that after foveal-sparing ILM peeling during vitrectomy for Type I epiretinal membrane.

METHODS

This was a prospective, randomized, comparative study. Thirty-eight eyes were randomized to undergo complete peeling of the ILM (CP group) or peeling with foveal sparing (FS group). The main outcome measures were foveal and perifoveal retinal sensitivity, visual acuity, and central retinal thickness.

RESULTS

Foveal retinal sensitivity showed a significant improvement in the FS group (2.82 ± 0.85 dB, P = 0.037) versus a slight drop in the CP group (-0.66 ± 0.48 dB, P = 1). Perifoveal retinal sensitivity slightly improved in both groups (0.47 ± 0.37 dB, P = 1 in the CP group and 0.79 ± 0.42 dB, P = 0.77 in the FS group), showing a similar trend without significant differences. Significant improvements were observed in both visual acuity and central retinal thickness in both groups. However, three cases in the FS group showed epiretinal membrane recurrence and required revision surgery with complete ILM removal.

CONCLUSION

Internal limiting membrane peeling may reduce retinal sensitivity and significantly increase the incidence of microscotomas. However, the higher epiretinal membrane recurrence rate after the foveal-sparing technique limits the effectiveness of this procedure. Further studies must be conducted to determine if it is safe to leave a portion of the ILM in front of the fovea.

Effect of Phacoemulsification on Outcomes after Vitrectomy with Membrane Peeling regarding New Intraretinal Cystoid Changes and Transient Macular Edema

PURPOSE

The aim of the present study was to analyze the effect of phacoemulsification on outcomes among patients undergoing vitrectomy with membrane peeling for idiopathic epiretinal membranes, with respect to new postoperative intraretinal cystoid changes and early transient macular edema.

PROCEDURES

This retrospective analysis included patients from 6 prospective studies, examining outcomes of 23G pars plana vitrectomy with membrane peeling due to idiopathic epiretinal membranes. Phacovitrectomy with membrane peeling was performed only in the case of coexisting vision affecting cataract. Optical coherence tomography was performed prior to surgery, in the first week, and 3 months after surgery.

RESULTS

In total, 183 patients were included. The occurrence of new postoperative intraretinal cystoid changes and early transient macular edema showed a trend toward being higher among patients undergoing phacovitrectomy with membrane peeling, compared to vitrectomy with membrane peeling alone, but it did not reach statistical significance (p = 0.5 and p = 0.186). The final best corrected distance visual acuity (BCVA) 3 months after surgery was significantly lower among patients with new postoperative intraretinal cystoid changes compared to patients without (with a median difference of 1 line between groups; p = 0.016).

CONCLUSIONS

New postoperative intraretinal cystoid changes and early transient macular edema are more frequent among patients undergoing phacovitrectomy with membrane peeling compared to patients with vitrectomy with membrane peeling alone.

Gene expression analysis identifies two distinct molecular clusters of idiopatic epiretinal membranes

Idiopathic epiretinal membranes (ERMs) are fibrocellular membranes containing extracellular matrix proteins and epiretinal cells of retinal and extraretinal origin. iERMs lead to decreased visual acuity and their pathogenesis has not been completely defined. Aim of this study was to provide a molecular characterization of iERMs by gene expression analysis. To this purpose, 56 iERMs obtained by pars plana vitrectomy were analyzed for the expression levels of genes encoding biomarkers of the cellular and molecular events occurring in iERMs. RT-qPCR analysis showed significant differences in the levels of cell population, extracellular matrix and cytokine/growth factor biomarkers among the iERMs investigated. Hierarchical clustering of RT-qPCR data identified two distinct iERM clusters, Cluster B samples representing transcriptionally "activated" iERMs when compared to transcriptionally "quiescent" Cluster A specimens. Further, Cluster B could be subdivided in two subgroups, Cluster B1 iERMs, characterized by a marked glial cell activation, and Cluster B2 samples characterized by a more pro-fibrotic phenotype. Preoperative decimal best-corrected visual acuity and post-surgery inner segment/outer grading values were higher in Cluster A patients, that showed a prevalence of fovea-attached type iERMs with near-normal inner retina, than in Cluster B patients, that presented more severe clinical and spectral domain optical coherence tomography (SD-OCT) features. In conclusion, this molecular characterization has identified two major clusters of iERM specimens with distinct transcriptional activities that reflect different clinical and SD-OCT features of iERM patients. This retrospective work paves the way to prospective whole-genome transcriptomic studies to allow a molecular classification of iERMs and for the identification of molecular signature(s) of prognostic and therapeutic significance.

Effect of Iatrogenic Traction during Macular Peeling Surgery on Postoperative Microperimetry

INTRODUCTION

Vitrectomy with peeling of epiretinal membrane (ERM) and internal limiting membrane offers the chance for improvement of metamorphopsia and visual acuity. Microscope integrated intraoperative optical coherence tomography (iOCT) enables real-time imaging of retinal alterations during peeling, such as intraoperative transient retinal thickening owing to tractional forces during peeling. The aim of our study was to measure the amounts of transient retinal thickening due to tractional forces during membrane peeling, as documented with iOCT, and to analyze possible effects on postoperative retinal function.

METHODS

This prospective, monocenter study included patients scheduled for pars plana vitrectomy with membrane peeling due to an idiopathic ERM. During peeling, an iOCT device (ReScan700, Carl Zeiss Meditec AG) with continuous OCT-assistance during the peeling procedure, and video documentation of the peeling procedure, was used for the assessment of intraoperative transient retinal thickening owing to tractional forces during peeling. Directly before and 3 months after surgery, macular-OCT scans and microperimetry were performed.

RESULTS

Twenty-five eyes of 25 patients were included in the study. Microperimetry could be performed in all patients, while iOCT documentation could be analyzed in 22 patients. Transient retinal thickening owing to tractional forces during peeling could be observed in 14 patients (64%), with a median thickening to 143% of the normal (preoperative) retinal thickness at that location (IQR 132-163). Six patients (24%) developed new deep microscotomata as seen in microperimetry 3 months after surgery, among them were 2 patients who also had transient retinal thickening during peeling.

CONCLUSION

New deep microscotomata developed only in a minority of patients with transient retinal thickening owing to tractional forces during peeling.

Vitreous and Vision Degrading Myodesopsia

Macromolecules comprise only 2% of vitreous, yet are responsible for its gel state, transparency, and physiologic function(s) within the eye. Myopia and aging alter collagen and hyaluronan association causing concurrent gel liquefaction and fibrous degeneration. The resulting vitreous opacities and collapse of the vitreous body during posterior vitreous detachment are the most common causes for the visual phenomenon of vitreous floaters. Previously considered innocuous, the vitreous opacities that cause floaters sometimes impact vision by profoundly degrading contrast sensitivity function and impairing quality-of-life. While many people adapt to vitreous floaters, clinically significant cases can be diagnosed with Vision Degrading Myodesopsia based upon echographic assessment of vitreous structure and by measuring contrast sensitivity function. Perhaps due to the ubiquity of floaters, the medical profession has to date largely ignored the plight of those with Vision Degrading Myodesopsia. Improved diagnostics will enable better disease staging and more accurate identification of severe cases that merit therapy. YAG laser treatments may occasionally be slightly effective, but vitrectomy is currently the definitive cure. Future developments will usher in more informative diagnostic approaches as well as safer and more effective therapeutic strategies. Improved laser treatments, new pharmacotherapies, and possibly non-invasive optical corrections are exciting new approaches to pursue. Ultimately, enhanced understanding of the underlying pathogenesis of Vision Degrading Myodesopsia should result in prevention, the ultimate goal of modern Medicine.

Elevated M2 Macrophage Markers in Epiretinal Membranes With Ectopic Inner Foveal Layers

Purpose

To analyze the differences in the vitreous cytokine profiles in epiretinal membrane eyes with and without an ectopic inner foveal layer (EIFL).

Methods

Sixty eyes with epiretinal membrane (32 eyes without EIFL and 28 eyes with EIFL) were included. The vitreous samples were collected during surgery for epiretinal membrane. The cytokine levels of the vitreous were measured using a multiplex bead analysis.

Results

The mean logMAR visual acuity was worse (0.42 vs. 0.37; P = 0.331) and the central foveal thickness was higher in the EIFL group (496.9 µm vs. 434.2 µm; P = 0.007) than they were in the group without EIFL. The mean EIFL thickness was 164.1 ± 67.7 µm in the EIFL group. On multiplex analysis of the vitreous cytokines, the levels of CD163 (21529 pg/dL vs. 10877 pg/dL; P = 0.002) and macrophage colony-stimulating factor (206 pg/dL vs. 159 pg/dL, P = 0.004) were significantly higher in the EIFL group than they were in the group without EIFL.

Conclusions

Eyes with EIFL had increased vitreous levels of M2 macrophage markers. The activation of glial cell proliferation by M2 macrophages may contribute to EIFL formation.

Negative correlation between retinal displacement and ganglion cell layer thickness changes in eyes with epiretinal membrane

PURPOSE

To examine retinal displacement after vitrectomy with internal limiting membrane peeling for epiretinal membrane treatment, and to determine the correlation between the extent of displacement and the ganglion cell layer thickness changes.

METHODS

Thirty-nine consecutive patients were evaluated. Optical coherence tomography was performed preoperatively, and 2 and 6 months postoperatively. The distance between the fovea, the vessel intersection in the superior nasal, superior temporal, inferior nasal, and inferior temporal macular regions, and the optic disk were measured. Ganglion cell layer thickness was recorded.

RESULTS

The distance from the optic disk to the fovea and the superior nasal and inferior nasal vessel intersections significantly reduced at 2 and 6 months. Ganglion cell layer thickness significantly decreased in all the subfields (except nasal) at 6 months. A significant negative correlation was found between the change in the ganglion cell layer thickness and the movement of the fovea toward the optic disk. The ganglion cell layer thickness changes significantly correlated with retinal displacement.

CONCLUSION

Retinal displacement toward the optic disk was detected after vitrectomy with internal limiting membrane peeling in eyes with epiretinal membrane. Ganglion cell layer thickness significantly reduced in all the subfields (except nasal). The extent of the displacement and the ganglion cell layer thickness changes showed significant negative correlation.

Spectral domain optical coherence tomography findings in myotonic dystrophy

The purpose of the study is to evaluate retinal involvement in a cohort of patients affected by Myotonic Dystrophy type 1 (DM1). Both eyes of 30 patients and one eye of a 31st patient with genetically proven diagnosis of DM1 and both eyes of 20 healthy age- and gender-matched subjects were enrolled. All patients underwent complete ophthalmologic examination including best-corrected visual acuity, intraocular pressure measurement, fundoscopy, fundus autofluorescence, infrared imaging and spectral-domain optical coherence tomography with central macular thickness measurement. DM1 patients showed statistically significant higher central macular thickness values than controls. In the DM1 group, butterfly (14.8%) and reticular (13.1%) pigment abnormalities were found with corresponding drusenoid deposit and focal disruption of photoreceptor and retinal pigment epithelium layers. Compared with the controls, DM1 group had higher prevalence of epiretinal membrane. In the DM1 group, the prevalence of epiretinal membrane and retinal pigment epithelium alterations were directly correlated with age, whereas no correlation was found with disease duration, CTG expansion and MIRS score. In conclusion, in addition to the typical retinal pigment epithelium changes, DM1 is also associated with abnormalities of the vitreoretinal interface, particularly epiretinal membrane, resulting in central macular thickness increase. Both inner and outer retinal alterations were associated with increasing age, suggesting that DM1 may cause a premature aging of the retina.

[Effect of Dyes Containing Lutein on Enhanced Visibility of Epiretinal Pathologies in Intraoperative OCT]

BACKGROUND

Epiretinal membranes are a disorder leading to metamorphopsia and loss in visual function. The gold standard in therapy is vitrectomy with membrane peeling, usually performed with chromovitrectomy. The aim of this study was to examine whether dyes containing lutein are capable of enhancing visualization of epiretinal tissue in intraoperative optical coherence tomography (iOCT).

PATIENTS AND METHODS

This was a prospective study that included 20 eyes of 20 patients with idiopathic epiretinal membranes scheduled for surgery. 23 G pars plana vitrectomy with intraoperative assistance of iOCT was performed in all cases. Staining of epiretinal membranes was performed with dyes containing trypan blue, brilliant blue G and lutein (tripledyne and dualdyne, both Kemin Industries Inc., USA).

RESULTS

In all patients (n = 20), staining of epiretinal tissue was good, and crystalline lutein particles could be well depicted in iOCT compared to soluble lutein that does not enhance visualisation of epiretinal tissue in iOCT.

CONCLUSIONS

The addition of lutein to commonly used dye formulations offers good staining properties and, in case of crystalline lutein, also enhances epiretinal tissue in iOCT.

Upregulated CD200 in pre-retinal proliferative fibrovascular membranes of proliferative diabetic retinopathy patients and its correlation with vascular endothelial growth factor

OBJECTIVE AND DESIGN

The objective was to determine the expression of CD200 in the pre-retinal proliferative fibrovascular membranes (PFVM) of patients with proliferative diabetic retinopathy (PDR) and to clarify its correlation with vascular endothelial growth factor (VEGF) and corresponding receptors.

METHODS

PFVM samples were collected by vitrectomy from 14 patients with PDR, and 11 non-diabetic patients who accepted vitrectomy for idiopathic epiretinal membranes removal. The expression of CD200, VEGF,VEGF-R1 and VEGF-R2 was measured via qPCR and immunofluorescent staining.

RESULTS

The mRNA level of CD200 was significantly higher in PDR patients than that in control patients. Meanwhile, CD200 and CD31 were found co-located and statistically associated in PFVM of PDR patients. The mRNA levels of VEGF, VEGF-R1 and VEGF-R2 were also significantly higher in PDR patients. Moreover, statistical association was found between CD200 and VEGF, VEGF-R1 in mRNA levels. But there was no significant correlationship between CD200 and VEGF-R2.

CONCLUSIONS

These results suggest a significantly increased expression of CD200 in PFVM of patients with PDR and present a crucial association between CD200 and VEGF-involved pathway. It represents a potential therapy that interfering with CD200 may inhibit the VEFG expression and neovascular formation in PDR patients.

Pneumatic Vitreolysis for the Treatment of Vitreomacular Traction Syndrome

Objectives:

To evaluate the posterior vitreous release rates after a single injection of expansile gas in patients with vitreomacular traction (VMT) syndrome with or without associated full-thickness macular hole (FTMH).

Materials and Methods:

Thirteen eyes of 12 consecutive patients with VMT (11 eyes) or VMT+FTMH (2 eyes) were reviewed retrospectively. Intravitreal injection of 0.3 mL of pure sulfur hexafluoride (SF6) (9 eyes) or perfluoropropane (C3F8) (4 eyes) was performed. Bobbing the head forward and backward similar to ‘drinking bird’ head movements was instructed until VMT release. Full ophthalmic examination and optical coherence tomography was performed at each visit.

Results:

VMT was released in all patients (100%) and mean release time was 5.2 days (1-19 days). Macular hole closure was not achieved in either of the two eyes with FTMH. Mean central subfield thickness decreased significantly from 361 μm to 263 μm (p=0.007). The mean pretreatment visual acuity was 0.44 LogMAR, which significantly improved to 0.25 LogMAR at the last visit (p=0.003). One of 13 eyes had retinal tear after the procedure which was successfully treated with laser retinopexy. Gas migration to the anterior chamber occurred in one patient. No other complications were observed.

Conclusion:

Pneumatic vitreolysis with C3F8 and SF6 gases is a relatively safe, low-cost, and minimally invasive treatment modality for VMT. However, FTMH closure could not be achieved with pneumatic vitreolysis.

Analysis of Clinical and Functional Results of the Developed Technology of Combined Laser Treatment of Initial Stages of Idiopathic Epiretinal Membrane

Aim. To analyze the clinical and functional results of the combined technology for laser treatment of patients with the initial stages of idiopathic epiretinal membrane.

Methods. This study included 3 groups of patients: the main group (32 patients) after the combined laser technology (subthreshold “grid” laser photocoagulation (LP) and subthreshold micropulse LP); control group (30 patients) which did not receive any treatment; comparison group (30 patients) after subthreshold “grid” LP. The assessment uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), central retinal thickness (CRT) and central retinal sensitivity (CRS) was performed. The follow-up period was 5 years.

Results. In the control group a slow decrease of UCVA, BCVA, CRS (p < 0.05) and an increasing CRT (p < 0.05) were observed. In the main group maximal UCVA, BCVA, CRS (p < 0.05) were marked from 3 to 6 months after laser treatment and there was a gradual decrease in the CRT indices. In the comparison group, a short-term positive effect was achieved up to 3 months with an increase of UCVA, BCVA, CRS (p < 0.05). 12 months post op there was an increase in CRT with a decrease of UCVA, BCVA, and CRS until the end of study.

Conclusion. The technology of combined laser treatment showed high efficiency in control and comparison groups, with stabilization/increase of UCVA, BCVA, CRS and stabilization/improvement of the morphological parameters of the retina – the decrease of CRT with ERM involution.

Microscopic Observation of Proliferative Membranes in Fibrocontractive Retinal Disorders

Proliferative membranes of fibrocontractive retinal disorders are extensively studied from the morphological and evolutive point of view. Despite this, little is known of their cellular composition. In this study, the authors investigated the morphological characteristics and cell composition of various types of surgically excised proliferative membranes and internal limiting membranes (ILMs), in order to provide new data supporting or challenging the pathogenic theories proposed until now. Sixty-nine specimens from 64 eyes of 64 consecutive patients were collected at surgery and subjected to a multilevel analysis by means of optical and electron microscopy. Membrane samples were semiquantitatively evaluated for the amount and distribution of cell nuclei and pigment. Immunohistochemical staining was performed with antibodies to alpha smooth muscle actin and CD68. Data were analyzed after grouping according to the following tissue types: ILM (20 specimens), epiretinal membrane (ERM) (22 specimens), ILM + ERM (20 specimens), and proliferative vitreoretinopathy (PVR) (7 specimens). The cell components found in the ERM specimens, like myofibroblasts, macrophages, and polymorphonuclear cells, were recognized as the expression of cell migration and differentiation that induced an inflammatory process and a fibroproliferative repair process. The detection of pigments in specific types of ERM, like those associated with lamellar macular hole (LMH) or secondary to retinal detachment (RD), diabetes, and PVR, suggested that retinal pigment epithelium (RPE) cells may have a role in the development of these vitreoretinal disorders. The reduction of the ERM cellularity with the patient's age supports the hypothesis that ERM evolves in time up to a fibrous tissue formation.

Combination laser therapy for epiretinal membrane: a physico-mathematical model

An epiretinal membrane (ERM) is a product of abnormal cell proliferation on the inner surface of the retina and at the vitreomacular interface. Laser therapy is an interesting modality for treating pathologies of the vitreomacular interface. The wise choice of laser settings (wavelength, exposure time, power) minimizes damage to the retina and ensures a good therapeutic effect. This could be a serious impetus to the development and refinement of laser technologies for treating ERM. This work investigates the biophysical response of structural retinal components, including the dynamics of temperatures and acoustic oscillations, protein denaturation, and stimulation of tissue regeneration, to a quasi-cw laser beam and a subsequent series of laser micropulses. The manuscript also analyzes the mechanisms underlying the therapeutic effect of the proposed laser therapy in patients with ERM.

Combined laser treatment of early idiopathic epiretinal membrane: clinical evaluation of the developed technique

Process of development of epiretinal membrane (ERM) on the retinal surface of macular area is one of the important problems associated with vitreoretinal pathologies. Up to the present day, there has not been developed an effective method to arrest fibrosis at the early stages of its development. This study aimed to evaluate efficacy and safety of the new combined laser technique designed to treat early idiopathic ERM (stages 0–1). Ninety-two patients aged 64.7 ± 9.6 years (mean) participated in the clinical research. They were divided into three groups: treatment group (n = 32), patients whose ERM was treated following the new combined laser technique; comparison group (n = 30), patients who underwent grid laser coagulation; control group (n = 30), no treatment, observation of the natural course. Based on the results of examination of the patients, we assessed uncorrected visual acuity, best corrected visual acuity, central retinal thickness, central retinal sensitivity. Assessed against the results registered in comparison and control groups, the developed combined laser treatment technique applied in the treatment group proved to be highly effective in maintaining/improving visual functional indicators and stabilizing/improving morphofunctional indicators throughout the entire period of observation. As pertains to the morphological and functional structures of sensory retina, the technique enabled retinal sensitivity improvement at different stages of observation, which reflects its safety and efficacy.

Vitrectomy for Diabetic Macular Edema: Optical Coherence Tomography Criteria and Pathology of the Vitreomacular Interface

PURPOSE

To correlate spectral-domain optical coherence tomography (SDOCT) criteria and clinical data with pathology of the vitreomacular interface (VMI) in eyes with diabetic macular edema (DME).

DESIGN

Retrospective cross-sectional study and laboratory investigation.

METHODS

We included specimens of 27 eyes of 26 patients with center-involved DME that underwent vitrectomy with peeling of the internal limiting membrane (ILM). Selection of specimens was consecutive and in retrospect using our register of the Vitreoretinal Pathology Unit. Clinical data and SDOCT examinations were correlated to immunocytochemistry and transmission electron microscopy. Classification of DME comprised sponge-like diffuse retinal thickening, cystoid macular edema, and serous retinal detachment. VMI was evaluated for presence of epiretinal membrane (ERM) and thickened vitreous cortex (tVC).

RESULTS

ERMs and tVC were found in all DME types. Diffuse DME showed tVC more often than cystoid DME. Hyalocytes, contractile myofibroblasts, glial cells, matrix metalloproteinases-2 and -9, and collagen type I, II, and III were positive tested irrespective of DME type. There were no significant cell fragments at the retinal side of the ILM. Visual acuity improved in the majority of cases and macular thickness decreased significantly during mean follow-up of 17 ± 10 months.

CONCLUSIONS

All eyes presented pathologic VMI changes irrespective of the OCT classification of DME type or presence of ERM. Composition of fibrocellular membranes at the VMI indicated remodeling of vitreous cortex and transdifferentiation of hyalocytes into myofibroblasts. Our findings might argue for an early surgical intervention in eyes with DME irrespective of the presence of traction formation imaged by SDOCT.