Inflammatory mechanisms of idiopathic epiretinal membrane formation

INCREASED RISK OF CYSTOID MACULAR EDEMA AFTER CATARACT SURGERY IN EYES PREVIOUSLY VITRECTOMIZED FOR IDIOPATHIC EPIRETINAL MEMBRANE

PURPOSE

To assess the rate and risk factors of cystoid macular edema (CME) both after isolated vitrectomy and after subsequent phacoemulsification in eyes with primary noncomplicated rhegmatogenous retinal detachment (RRD) or idiopathic epiretinal membrane (ERM).

METHODS

Retrospective observation of institutional patients undergoing vitrectomy for RRD or vitrectomy with internal limiting membrane peeling for ERM from 2016 to 2021, further analyzing those who later underwent phacoemulsification. The CME rate was assessed within the first 6 months after both vitrectomy and cataract surgery.

RESULTS

The authors included 187 phakic eyes with ERM and 311 with RRD undergoing isolated vitrectomy. Postvitrectomy CME occurred in 12.8% of ERM cases compared with 1% in RRD cases ( P < 0.0001). Stage-4 ERMs and intraoperative laser were found associated with CME. After uncomplicated phacoemulsification, the CME rate was higher in eyes vitrectomized for ERM (13.8%) compared with RRD (2%, P = 0.0055). Postvitrectomy CME was found to be associated with an increased risk of postcataract CME (odds ratio 13.588, P = 0.0187).

CONCLUSION

In eyes undergoing phacoemulsification postvitrectomy, the risk of CME is higher when vitrectomy was performed for ERM compared with RRD. The ERM-related intraretinal changes, together with the required surgical stress, may play a role in making these eyes more susceptible to CME.

Association of intravitreal and topical anti-inflammatory therapies on short-term anatomical and functional outcomes following epiretinal membrane surgery

PURPOSE

Here we examine the association of anti-inflammatory therapy with anatomical and functional outcomes of epiretinal membrane surgery.

METHODS

The study included consecutive patients having gone through epiretinal membrane surgery at Helsinki University Hospital, Finland, between 2017 and 2021. The association of perioperative intravitreal and postoperative topical anti-inflammatory therapies with surgical outcomes was assessed.

RESULTS

In total, 214 eyes of 214 patients with a mean age of 71.2 ± 8.2 years were studied. At 1-month, perioperative intravitreal use of triamcinolone acetonide (n = 27) was associated with a significant proportional and absolute improvement in foveal thickness (-15.9 ± 18.4% vs. -4.2 ± 25.6%, p = 0.003 and -86.2 ± 109.6 μm vs. -33.7 ± 94.3 μm, p = 0.004), and central subfield macular thickness (-14.7 ± 16.5% vs. -6.3 ± 16.9%, p = 0.009 and -80.6 ± 102.8 μm vs. -36.1 ± 75.9 μm, p = 0.004) when compared to those without triamcinolone acetonide. Furthermore, best-corrected visual acuity (BCVA) gain showed a non-significant yet corresponding trend favouring intraoperative intravitreal use of triamcinolone acetonide (0.21 ± 0.27 vs. 0.09 ± 0.28 LogMAR units, p = 0.062). Postoperative use of topical non-steroidal anti-inflammatory drugs (NSAIDs) (n = 36) as adjunct therapy showed no significant advantage in anatomical outcomes or BCVA gain when compared to those without NSAIDs (all p > 0.05). Triamcinolone acetonide remained significant for proportional and absolute improvement in foveal thickness (p = 0.019 and p = 0.006) and in central subfield macular thickness (p = 0.013 and p = 0.006) when controlled for confounding factors patient age and gender and topical NSAID use.

CONCLUSIONS

Intraoperative intravitreal use of triamcinolone acetonide improved short-term anatomical outcomes in patients who underwent epiretinal membrane surgery.

The effect of diabetes on short-term outcomes following epiretinal membrane surgery

PURPOSE

This study aimed to examine the association of diabetes with anatomical and functional outcomes of epiretinal membrane surgery.

METHODS

Consecutive patients who underwent epiretinal membrane surgery between 2017-2021 at Helsinki University Hospital, Finland. Here we examined the association of diabetes, glycemic control, and requirement for insulin medication with surgical outcomes at 1-month.

RESULTS

Included were 214 eyes of 214 patients, with a mean age of 71.2 ± 8.2 years. Among patients with diabetes (n = 45), neither significant differences were observed in anatomical outcomes (- 47.8 ± 72.7 μm vs. - 38.3 ± 103 μm for foveal thickness, p = 0.566 and - 41.6 ± 61.8 μm vs. - 41.7 ± 85.7 μm for central subfield macular thickness, p = 0.996) nor in best-corrected visual acuity (BCVA) gain (0.06 ± 0.22 vs 0.12 ± 0.30 LogMAR units, p = 0.214) compared to those without diabetes. In a multivariate analysis adjusted for age, gender, the existence of preoperative macular cysts, and topical nonsteroidal anti-inflammatory drugs (NSAIDs) use, the results remained consistent. The last preoperative HbA1c levels did not correlate with changes in foveal (Pearson's r = 0.218, p = 0.264) or central subfield macular thickness (r = 0.365, p = 0.056), or with BCVA gain (r = -0.177, p = 0.386). Insulin therapy for diabetes did not associate with the outcomes (p > 0.05 for anatomical and functional comparisons).

CONCLUSIONS

In a cohort of patients who underwent epiretinal membrane surgery, neither the presence of diabetes, nor glycemic control and the use of insulin medication associated with the outcomes.

Epiretinal Membrane: Correlations Among Clinical, Immunohistochemical, and Biochemical Features and Their Prognostic Implications

Purpose

To investigate correlations among clinical, immunohistochemical, and biochemical characteristics of epiretinal membranes (ERMs) and their prognostic implications.

Methods

This prospective study included 120 patients with idiopathic ERM who underwent vitrectomy. Preoperative and postoperative best-corrected visual acuity (BCVA) and optical coherence tomography (OCT) were measured. Surgical ERM tissues underwent immunohistochemistry (IHC) analysis, and vitreous samples were analyzed for cytokine levels. Statistical analysis assessed associations among BCVA, OCT metrics (ERM stage, inner-retinal irregularity index [IRII], ellipsoid zone disruption [EZD]), IHC features (cell density, protein expression), and cytokines.

Results

The average age of the participants was 70.2 ± 7.6 years, and ERM stages were distributed as Stage 2 in 34 eyes (28.3%), Stage 3 in 54 eyes (45.0%), and Stage 4 in 32 eyes (26.7%). Advancing ERM stage was linked with worsening visual outcomes, higher preoperative IRII, increased EZD incidence, increased ERM cellularity, and elevated TGF-β1 level. Protein expression for myofibroblasts (αSMA), glial cells (GFAP), hyalocytes (CD45), and retinal pigment epithelium (RPE) cells (PRPH2) correlated positively with ERM stage. Multivariate analysis showed preoperative IRII significantly correlated with preoperative BCVA, GFAP, PRPH2, and type I collagen. TGF-β1 was significantly associated with preoperative IRII, αSMA, type I collagen, and N-cadherin, but not with postoperative BCVA. Postoperative BCVA was significantly correlated with preoperative BCVA, preoperative IRII, preoperative EZD, αSMA, and PRPH2.

Conclusions

Early-stage ERM is associated with better visual prognosis, fewer inner and outer retinal changes in OCT, and fewer epithelial-mesenchymal transition-related alterations in ERM tissues. Key prognostic indicators for postoperative BCVA include preoperative BCVA, IRII, EZD, myofibroblasts, and RPE cells. TGF-β1 promotes the transdifferentiation of intraocular cells, impacting OCT features directly and visual outcomes indirectly.

Epiretinal membrane: an overview and update

Epiretinal membrane (ERM) is a frequently diagnosed macular disease associated with aging, characterized by a fibrous membrane forming on the internal limiting membrane (ILM) and leading to visual dysfunctions such as metamorphopsia. Various hypotheses regarding the pathology of metamorphopsia have been proposed; however, the complete pathophysiologic mechanism underlying ERM remains unclear. Optical coherence tomography (OCT) provides detailed images enabling precise diagnosis and characterization of ERM, with several recent studies using the latest OCT imaging techniques. Surgical removal of ERM is the only treatment option; however, criteria for surgical intervention are not established, complicating the decision-making processes. Furthermore, the debate on whether simultaneous peeling of the ILM during ERM surgery enhances outcomes or poses unnecessary risks is ongoing, with no definite conclusion having yet been reached. This review also focuses on epiretinal proliferation, which is different from ERM and is characteristic of lamellar macular hole (LMH). Recently, diagnostic criteria for LMH and related diseases were proposed. Reports on effective surgical procedures for LMH exist, although more research is needed to confirm the long-term outcomes. Thus, this review article aims to provide an overview and updated knowledge of ERM, LMH, and related diseases.

Tenascin-C induces transdifferentiation of retinal pigment epithelial cells in proliferative vitreoretinopathy

Proliferation and transdifferentiation of the retinal pigment epithelium (RPE) are hallmarks of proliferative vitreoretinopathy (PVR); however, the critical regulators of this process remain to be elucidated. Here, we investigated the role of tenascin-C in PVR development. In vitro, exposure of human ARPE-19 (hRPE) cells to TGF-β2 increased tenascin-C expression. Tenascin-C was shown to be involved in TGF-β2-induced transdifferentiation of hRPE cells, which was inhibited by pretreatment with tenascin-C siRNA. In PVR mouse models, a marked increase in the expression of tenascin-C mRNA and protein was observed. Additionally, immunofluorescence analysis demonstrated a dramatic increase in the colocalization of tenascin-C with RPE65 or α-smooth muscle actin(α-SMA) in the epiretinal membranes of patients with PVR. There was also abundant expression of integrin αV and β-catenin in the PVR membranes. ICG-001, a β-catenin inhibitor, efficiently attenuated PVR progression in a PVR animal model. These findings suggest that tenascin-C is secreted by transdifferentiated RPE cells and promotes the development of PVR via the integrin αV and β-catenin pathways. Therefore, tenascin-C could be a potential therapeutic target for the inhibition of epiretinal membrane development associated with PVR.

Immunohistochemical expression of Fibrillin-1 in idiopathic epiretinal membranes

PURPOSE

To investigate the expression patterns of Fibrillin-1 in idiopathic epiretinal membranes (iERM) and identify Fibrillin-1-secreting cells.

METHODS

iERM samples were collected via standard 27-gauge vitrectomy and subsequently subjected to flat-mount immunohistochemistry with double staining for the following markers: Fibrillin-1, glial acidic fibrillary protein (GFAP), cellular retinaldehyde-binding protein (CRALBP), retinoid isomerohydrolase RPE65 (RPE65), and α-smooth muscle actin (α-SMA).

RESULTS

Fibrillin-1 was detected throughout the iERM. The colocalization of Fibrillin-1 with α-SMA, CRALBP, and RPE65 suggested that myofibroblasts and retinal pigment epithelial (RPE) cells secreted Fibrillin-1. The lack of colocalization between GFAP and Fibrillin-1 indicated that GFAP-positive glial cells did not secrete Fibrillin-1. The colocalization of CRALBP and RPE65 with α-SMA indicated the transformation of RPE cells into myofibroblasts. This suggested that RPE cells transformed into myofibroblasts and secreted Fibrillin-1. The lack of colocalization between GFAP and α-SMA implied that GFAP-positive glial cells did not express α-SMA.

CONCLUSIONS

Fibrillin-1 is widely distributed in iERMs, and myofibroblasts were the primary sources of Fibrillin-1 secretion. Additionally, during their transformation into myofibroblasts, RPE cells secreted Fibrillin-1. GFAP-positive glial cells did not express α-SMA nor secrete Fibrillin-1.

KEY MESSAGES

What is known Idiopathic epiretinal membranes are a common cause of visual acuity and quality impairment. The protein and cell components of idiopathic epiretinal membrane exhibit diversity. What is new Fibrillin-1 is present throughout the idiopathic epiretinal membrane. Myofibroblasts are the most important source of Fibrillin-1 secretion. Retinal pigment epithelial cells also secrete Fibrillin-1 when transforming into myofibroblast. Glial cells do not transform to myofibroblast and do not secrete Fibrillin-1.

ADAPTIVE OPTICS AND MULTIMODAL IMAGING FOR INFLAMMATORY VITREORETINAL INTERFACE ABNORMALITIES

PURPOSE

To investigate changes to the vitreoretinal interface in uveitis with multimodal imaging including adaptive optics.

METHODS

Four eyes (four patients) affected by fovea-attached (subtype 1A) or fovea-sparing epiretinal membranes (ERMs) on spectral-domain optical coherence tomography or visible internal limiting membrane (ILM) on infrared scanning laser ophthalmoscope (SLO) fundus imaging were recruited in this pilot study. The microstructure of the vitreoretinal interface was imaged using flood-illumination adaptive optics (FIAO), and the images were compared with the cross-sectional spectral-domain optical coherence tomography data.

RESULTS

Adaptive optics images revealed multiple abnormalities of the vitreoretinal interface, such as deep linear striae in ERM, and hyperreflective microstructures at the location of ERMs and ILMs. The cone mosaic was imaged by FIAO and was found altered in the four eyes with ERMs or visible ILM. The same four eyes presented alteration of photopic 30 Hz flicker that was reduced in amplitude indicating cone inner retinal layer dysfunction.

CONCLUSION

FIAO imaging can identify specific patterns associated with ERMs and ILMs. Correlating FIAO imaging of the vitreomacular interface with the structural alterations seen in FIAO at the level of the outer retinal structures can help understand the cause of significant macular dysfunction associated with ERM.

Follow-up in a point-of-care diabetic retinopathy program in Pittsburgh: a non-concurrent retrospective cohort study

BACKGROUND

The Point-of-Care Diabetic Retinopathy Examination Program (POCDREP) was initiated in 2015 at the University of Pittsburgh/UPMC in response to low diabetic retinopathy (DR) examination rates, a condition affecting a quarter of people with diabetes mellitus (PwDM) and leading to blindness. Early detection and treatment are critical with DR prevalence projected to triple by 2050. Approximately, half of PwDM in the U.S. undergo yearly examinations, and there are reported varying follow-up rates with eye care professionals, with limited data on the factors influencing these trends. POCDREP aimed to address screening and follow-up gap, partnering with diverse healthcare entities, including primary care sites, free clinics, and federally qualified health centers.

METHODS

A non-concurrent retrospective cohort study spanning 2015-2018 examined data using electronic health records of patients who underwent retinal imaging. Imaging was performed using 31 cameras across various settings, with results interpreted by ophthalmologists. Follow-up recommendations were made for cases with vision-threatening DR (VTDR), incidental findings, or indeterminate results. Factors influencing follow-up were analyzed, including demographic, clinical, and imaging-related variables. We assessed the findings at follow-up of patients with indeterminate results.

RESULTS

Out of 7,733 examinations (6,242 patients), 32.25% were recommended for follow-up. Among these, 5.57% were classified as having VTDR, 14.34% had other ocular findings such as suspected glaucoma and age-related macular degeneration (AMD), and 12.13% were indeterminate. Of those recommended for follow-up, only 30.87% were assessed by eye care within six months. Older age, marriage, and severe DR were associated with higher odds of following up. Almost two thirds (64.35%) of the patients with indeterminate exams were found with a vision-threatening disease at follow-up.

CONCLUSION

The six-month follow-up rate was found to be suboptimal. Influential factors for follow-up included age, marital status, and the severity of diabetic retinopathy (DR). While the program successfully identified a range of ocular conditions, screening initiatives must extend beyond mere disease detection. Ensuring patient follow-up is crucial to DR preventing programs mission. Recommended strategies to improve follow-up adherence include education, incentives, and personalized interventions. Additional research is necessary to pinpoint modifiable factors that impact adherence and to develop targeted interventions.

Aqueous Humor Cytokines in Idiopathic Epiretinal Membrane: Correlation with Disease Severity

BACKGROUND

To analyze the concentration of aqueous humor (AH) cytokines in eyes with idiopathic epiretinal membrane (iERM) and to investigate their potential correlation with disease severity.

METHODS

Retrospective cross-sectional case-control institutional study. A total of 16 eyes of 16 iERM patients and 14 eyes of 14 age-matched healthy controls were enrolled. AH samples were analyzed for various biomarkers using a glass-chip protein array. Cytokines associated with inflammation, fibrosis, angiogenesis, and glial signal transduction were quantified.

RESULTS

Significant differences in cytokine concentration were observed between the iERM group and controls, with 19 cytokines elevated in the iERM group (among them IL-6, IL-8, PDGF-AB, PDGF-BB, TGFB-1, TGFB-2, TGFB-3, VEGF A, VEGF C, VEGF D, p < 0,05, 95% confidence interval). Correlation analysis revealed associations between cytokine levels and iERM severity. Notably, stages 2, 3, and 4 of iERM demonstrated increased levels of various biomarkers.

CONCLUSIONS

This study provides insights into the complex molecular interactions underlying iERM pathogenesis, describing a correlation between neuroinflammation and iERM severity.

Can wall shear-stress topology predict proliferative vitreoretinopathy localization following pars plana vitrectomy?

We numerically study the fluid dynamics of oil tamponade in models of vitrectomized eyes prompted by a subset of daily activities corresponding to movements on the horizontal plane with the patient in a standing position. Bulk flow features are related to near-wall flow topology and transport at the retinal surface through a wall shear-stress-based analysis. Proliferative VitreoRetinopathy (PVR) is the leading cause of retinal re-detachment occurring in about 20% of all cases due to the accumulation of inflammatory cells in discrete retinal regions. Signalling soluble mediators stimulate inflammatory cells' chemotaxis and studying their distribution across the retinal surface may acquire clinical relevance. In all the investigated cases, persistent and elongated regions along the retina, potentially prone to accumulate chemo-attractants and cells are observed. Gradients of soluble inflammation mediators present in the aqueous are known responsible for the so-called epithelial-mesenchymal transition that initiates PVR and favours recurrent retinal detachment prompting the proliferation of inflammatory cells with collagen matrix deposition and its contraction. The surgical apposition of encircling scleral buckling elements, known for over a century to influence PVR formation and localization, modifies the attracting regions, possibly causing an accumulation of molecules and cells along approximately vertical lines that follow the rising menisci due to the cerclage indentation. The resulting spatial pattern is compatible with clinical observations. This study may open toward rational analyses of near-wall transport to predict PVR pathogenesis by relating biochemical accumulation in certain areas of the retina to clinical conditions.

Intravitreal allogeneic mesenchymal stem cells: a non-randomized phase II clinical trial for acute non-arteritic optic neuropathy

BACKGROUND

An effective treatment for acute non-arteritic ischemic optic neuropathy (NA-AION) has not been known or proven yet. Previous studies have suggested a neuroprotective effect of allogeneic bone marrow-derived mesenchymal stem cells. This study aims to report the results of a clinical trial on patients with acute non-arteritic optic neuropathy (NA-AION) treated with an intravitreal injection of allogeneic bone marrow-derived mesenchymal stem cells (BM-MSCs) (MSV®).

METHODS

We conducted a prospective, non-randomized, clinical phase-II study (Eudra CT number 2016-003029-40; ClinicalTrials.gov Registry NCT03173638) that included 5 patients with acute unilateral NA-AION diagnosed within 2 weeks after symptom onset and who received an intravitreal injection of allogeneic BM-MSCs (0.05 ml; cell concentration: 1.5 × 106cells/mL). The patients underwent regular ophthalmological examinations and were followed for one year.

RESULTS

In this trial, allogeneic BM-MSCs appeared to be safe as no patients developed signs of acute nor chronic intraocular inflammation or a significant change in intraocular pressure, although an epiretinal membrane was developed in one patient. A retrolental aggregate formed shortly after the injection spontaneously disappeared within a few weeks in another phakic patient, leaving a subcapsular cataract. Visual improvement was noted in 4 patients, and amplitudes of P100 on the visually evoked potentials recordings increased in three patients. The retinal nerve fiber layer and macular ganglion cell layer thicknesses significantly decreased during the follow-up.

CONCLUSIONS

Besides the development of an epiretinal membrane in one patient, the intravitreal application of allogeneic BM-MSCs appeared to be intraocularly well tolerated. Consequently, not only NA-AION but also BM-MSCs deserve more clinical investigational resources and a larger randomized multicenter trial that would provide stronger evidence both about safety and the potential therapeutic efficacy of intravitreally injected allogeneic BM-MSCs in acute NA-AION.

TRIAL REGISTRATION

Safety Assessment of Intravitreal Mesenchymal Stem Cells for Acute Non-Arteritic Anterior Ischemic Optic Neuropathy (NEUROSTEM). NCT03173638. Registered June 02, 2017 https://clinicaltrials.gov/ct2/show/NCT03173638 .

Epiretinal Membrane Impairs the Inner Retinal Layer in a Traction Force-Dependent Manner

Purpose

To investigate the relationship between retinal traction force and impairment of the inner retinal layer in patients with epiretinal membrane (ERM).

Design

Nonrandomized, retrospective consecutive case series.

Participants

Two hundred nine eyes of 201 patients with idiopathic ERM who underwent vitrectomy for idiopathic ERM were enrolled.

Methods

Retinal folds caused by ERM were visualized using en face OCT, and the maximum depth of retinal folds within the parafovea (MDRF) was measured. Focal macular electroretinogram (ERG) was used to measure the amplitude and implicit time of each component for the ERM eyes and the normal fellow eyes. B-scan OCT images were used to measure the thicknesses of the inner nuclear layer (INL) and outer nuclear layer (ONL) + outer plexiform layer (OPL). Expression of α-smooth muscle actin (α-SMA) in surgically removed ERM specimens was quantified by reverse-transcription polymerase chain reaction.

Main Outcome Measures

We analyzed the relationship between MDRF and the relative amplitudes of focal macular ERG (affected eye/fellow eye), the relationships between MDRF and the mean INL thickness and ONL+OPL thickness, comparison of INL thickness and ONL+OPL thickness for each area when cases were classified according to MDRF localization in the ETDRS chart, and the relationship between MDRF and the relative expression of α-SMA in the ERM specimens.

Results

The MDRF significantly correlated with the relative amplitudes (affected eye/fellow eye) of b-waves and oscillatory potentials (r = -0.657, P = 0.015; r = -0.569, P = 0.042, respectively) and the mean INL thickness and ONL+OPL thickness (r = 0.604, P < 0.001; r = 0.210, P = 0.007, respectively). However, only the INL thickness progression rate was significantly correlated with the MDRF progression rate (r = 0.770, P < 0.001). On case stratification by localization of MDRF based on the ETDRS chart, in regions other than temporal regions, the INL thickness was significantly greater in regions with MDRF than in other regions. The MDRF significantly correlated with α-SMA expression in the ERM specimens (r = 0.555, P = 0.009).

Conclusions

The findings suggest that ERM impairs the inner retinal layer in a traction force-dependent manner.

Financial Disclosures

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

Pathophysiology and clinical aspects of epiretinal membrane - review

The epiretinal membrane (ERM) is a pathological tissue formed at the vitreoretinal interface. The formation of this tissue is associated with numerous symptoms related to disturbances of vision. These types of lesions may arise idiopathically or be secondary to eye diseases, injuries and retinal surgeries. ERM tissue contains numerous cell types and numerous cytokines, which participate in its formation. The aim of this paper is to summarize information about the etiology, epidemiology, pathophysiology and treatment of ERM, with a brief description of the main cells that build the ERM - as well as the cytokines and molecules related to ERM pathogenesis - being provided in addition.

TOPOGRAPHIC ASSESSMENT OF INTRARETINAL CYSTOID SPACE AND ITS PROGNOSTIC VALUES IN IDIOPATHIC EPIRETINAL MEMBRANE

PURPOSE

To assess the topographical distribution of intraretinal cystoid space (IRC) and its prognostic value in idiopathic epiretinal membrane (iERM).

METHODS

One hundred twenty-two eyes of iERM that had been followed up for 6 months after membrane removal were included. Based on the baseline IRC distribution, the eyes were divided into Groups A, B, and C (absence, IRC within 3 mm, and 6 mm from the fovea, respectively). The best-corrected visual acuity (BCVA), central subfield macular thickness (CSMT), ectopic inner foveal layer, and microvascular leakage (ML) were assessed.

RESULTS

Fifty-six eyes (45.9%) had IRC, of which 35 (28.7%) were in Group B and 21 (17.2%) in Group C at baseline. Compared with group B, group C showed worse BCVA, thicker CSMT, and a greater association with ML (OR = 5.415; P = 0.005) at baseline; and also presented with worse BCVA, thicker CSMT, and wider distribution of IRC postoperatively. A wide distribution of IRC was an unfavorable baseline factor in achieving good visual acuity (OR = 2.989; P = 0.031).

CONCLUSION

Widely distributed IRCs were associated with advanced disease phenotype as poor BCVA, thick macula, and baseline ML in iERM and also showed a poor visual outcome after membrane removal.

Retinal Angiomatous Proliferation in a Patient with Retinitis Pigmentosa

Retinal angiomatous proliferation (RAP) and other types of choroidal neovascularization (CNV) are very rarely reported in patients with retinitis pigmentosa (RP). We present a case report of a 91-year-old patient with an obvious RP phenotype, who presented with a sudden onset of vision worsening and metamorphopsia in the left eye. Genetic testing on the UK inherited retinal disease panel did not identify a pathogenic variant. Multimodal imaging comprising optical coherence tomography (OCT), OCT angiography, and fluorescein and indocyanine green angiography showed a RAP lesion in the left macula. The patient received three treatments of monthly injections of aflibercept, with excellent morphological and functional outcomes. Taking into account the patient's age at presentation of the RAP lesion, it is not clear whether the RAP was associated or coincidental with RP. This case report highlights the importance of possessing an awareness that RAP lesions can occur in RP. Moreover, due to a good response and potential safety concerns with continuous anti-VEGF injections in RP patients, a pro re nata (PRN) regimen might be the safest option.

Phosphorylation of αB-Crystallin Involves Interleukin-1β-Mediated Intracellular Retention in Retinal Müller Cells: A New Mechanism Underlying Fibrovascular Membrane Formation

Purpose

Chronic inflammation plays a pivotal role in the pathology of proliferative diabetic retinopathy (PDR), in which biological alterations of retinal glial cells are one of the key elements. The phosphorylation of αB-crystallin/CRYAB modulates its molecular dynamics and chaperone activity, and attenuates αB-crystallin secretion via exosomes. In this study, we investigated the effect of phosphorylated αB-crystallin in retinal Müller cells on diabetic mimicking conditions, including interleukin (IL)-1β stimuli.

Methods

Human retinal Müller cells (MIO-M1) were used to examine gene and protein expressions with real-time quantitative PCR, enzyme linked immunosorbent assay (ELISA), and immunoblot analyses. Cell apoptosis was assessed by Caspase-3/7 assay and TdT-mediated dUTP nick-end labeling staining. Retinal tissues isolated from the Spontaneously Diabetic Torii (SDT) fatty rat, a type 2 diabetic animal model with obesity, and fibrovascular membranes from patients with PDR were examined by double-staining immunofluorescence.

Results

CRYAB mRNA was downregulated in MIO-M1 cells with the addition of 10 ng/mL IL-1β; however, intracellular αB-crystallin protein levels were maintained. The αB-crystallin serine 59 (Ser59) residue was phosphorylated with IL-1β application in MIO-M1 cells. Cell apoptosis in MIO-M1 cells was induced by CRYAB knockdown. Immunoreactivity for Ser59-phosphorylated αB-crystallin and glial fibrillary acidic protein was colocalized in glial cells of SDT fatty rats and fibrovascular membranes.

Conclusions

The Ser59 phosphorylation of αB-crystallin was modulated by IL-1β in Müller cells under diabetic mimicking inflammatory conditions, suggesting that αB-crystallin contributes to the pathogenesis of PDR through an anti-apoptotic effect.

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.

Variability of Visual Recovery with Time in Epiretinal Membrane Surgery: A Predictive Analysis Based on Retinal Layer OCT Thickness Changes

Purpose: To correlate postoperative optical coherence tomography (OCT) thickness changes of each retinal layer with different patterns of visual recovery after idiopathic epiretinal membrane (ERM) surgery in a cohort of patients showing no known risk factors for poor visual recovery at preoperative imaging. Methods: Best corrected visual acuity (BCVA) and OCT images were acquired preoperatively and 1 month, 3 months and 6 months postoperatively. Patients were divided into four groups according to postoperative BCVA improvement: improvement < 15 ETDRS letters (GROUP 1), immediate improvement of BCVA without further improvements at later follow-ups (GROUP 2), immediate improvement of BCVA with further improvements at later follow-ups (GROUP 3) and delayed improvement of BCVA (GROUP 4). Results: Eighty-five patients were included. GROUP1 was the only one characterized by retinal nerve fiber layer (RNFL) thickness increase and ganglion cell layer/central macular thickness (GCL/CMT) ratio decrease at 1 month and outer nuclear layer (ONL) thickness decrease at 3 and 6 months. GROUP 2 was the only one showing a decrease in GCL/inner plexiform layer (GCL/IPL) ratio at 1 month. GROUP 3 and 4 showed higher preoperative RNFL thickness compared to the other, and GROUP 4 manifested a late increase in RNFL thickness at 6 months. Conclusions: Different patterns of VA recovery are associated with specific layer thickness changes. If further confirmed, this would help detect those cases characterized by poor or delayed visual recovery despite the absence of other known imaging risk factors.

Effect of Internal Limiting Membrane Peeling or Not on Blood Flow Signal in Macular Area of Diabetic Patients with Preretinal Membrane

PURPOSE

To study the effect of intraoperative internal limiting membrane (ILM) peeling on the macular vascular structure in patients with diabetic epiretinal membrane (ERM).

METHODS

Patients with diabetic ERM were divided into an ERM + ILM peeling group (18 eyes) and an ERM peeling group (19 eyes), all of whom underwent standard vitrectomy and were followed up until 6 months postoperatively. Best-corrected visual acuity (BCVA), Central macular thickness (CMT), Vessel density (VD) and vessel length density (VLD) of the superficial as well as deep retinal capillary plexus were compared between the two groups.

RESULTS

There was no significant difference in BCVA (p = .188, .410, .901, .916) and CMT (p = .164, .128, .110, .105) between the two groups at the week 1, month 1, month 3 and month 6 after operation. In the superficial capillary plexus (SCP), the change in VD (p = .106) and VLD (p = .438) was not affected by ILM peeling, and there was no significant difference in VD (p = .154, .063, .100, .162) and VLD (p = .386, .263, .431, .391) between the two groups during the four follow-up after operation. For the deep capillary plexus (DCP), there was an effect of ILM peeling on the changes in VD (p = .024) and VLD (p = .012), ILM peeling delayed the recovery time of the VD and VLD; The VD (p = .026, .000, .003) and VLD (p = .005, .000, .000) of ERM + ILM peeling group were lower than those of ERM peeling group from the month 1 to the month 6 after operation.

CONCLUSION

Intraoperative peeling of the ILM in patients with diabetic ERM delayed the improvement of blood flow signal in the DCP but did not affect the recovery of postoperative BCVA and CMT.

Short-Term In Vitro ROS Detection and Oxidative Stress Regulators in Epiretinal Membranes and Vitreous from Idiopathic Vitreoretinal Diseases

Background

A plethora of inflammatory, angiogenic, and tissue remodeling factors has been reported in idiopathic epiretinal membranes (ERMs). Herein we focused on the expression of a few mediators (oxidative, inflammatory, and angiogenic/vascular factors) by means of short-term vitreal cell cultures and biomolecular analysis.

Methods

Thirty-nine (39) ERMs and vitreal samples were collected at the time of vitreoretinal surgery and biomolecular analyses were performed in clear vitreous, vitreal cell pellets, and ERMs. ROS products and iNOS were investigated in adherent vitreal cells and/or ERMs, and iNOS, VEGF, Ang-2, IFNγ, IL18, and IL22 were quantified in vitreous (ELISA/Ella, IF/WB); transcripts specific for iNOS, p65NFkB, KEAP1, NRF2, and NOX1/NOX4 were detected in ERMs (PCR). Biomolecular changes were analyzed and correlated with disease severity.

Results

The higher ROS production was observed in vitreal cells at stage 4, and iNOS was found in ERMs and increased in the vitreous as early as at stage 3. Both iNOS and NOX4 were upregulated at all stages, while p65NFkB was increased at stage 3. iNOS and NOX1 were positively and inversely related with p65NFkB. While NOX4 transcripts were always upregulated, NRF2 was upregulated at stage 3 and inverted at stage 4. No significant changes occurred in the release of angiogenic (VEGF, Ang-2) and proinflammatory (IL18, IL22 and IFNγ) mediators between all stages investigated.

Conclusions

ROS production was strictly associated with iNOS and NOX4 overexpression and increased depending on ERM stadiation. The higher iNOS expression occurred as early as stage 3, with respect to p65NFkB and NRF2. These last mediators might have potential prognostic values in ERMs as representative of an underneath retinal damage.

Correlations between Clinical and Histopathologic Characteristics in Idiopathic Epiretinal Membrane

PURPOSE

To investigate correlations between clinical and histopathologic characteristics of idiopathic epiretinal membrane (ERM).

DESIGN

Retrospective interventional case series.

PARTICIPANTS

In total, 87 eyes from 87 patients with idiopathic ERM who underwent pars plana vitrectomy with peeling of the ERM from 2019 to 2020 were included.

METHODS

The outcomes of clinical ophthalmic examination, including measurement of best-corrected visual acuity (BCVA) and spectral-domain OCT (SD-OCT), before and after surgery were reviewed. Surgical specimens were fixed in formalin and embedded in paraffin for histologic and immunohistochemical analysis.

MAIN OUTCOMES MEASURES

The association between morphological characteristics revealed on SD-OCT images and the cellular composition of the surgically excised ERM demonstrated with immunohistochemical staining were the main outcome measures. Changes in the BCVA and central macular thickness (CMT) were assessed through a comparison of preoperative and postoperative measurements.

RESULTS

Based on SD-OCT morphological characteristics in the foveal area, 15 cases were classified into group 1A (mainly outer retinal thickening), 39 into group 1B (more tenting of the outer retina and distorted inner retina), and 33 into group 1C (prominent inner retina thickening). Overall, postoperative final BCVA and CMT at 1 year improved in all groups. Patients who presented with a better initial BCVA exhibited a more favorable final BCVA. Epiretinal membranes in group 1C demonstrated the greatest decrease in CMT compared with those in groups 1B and 1A, but the final CMT did not differ among the groups. A negative correlation between the density of hyalocytes (P = 0.003) and myofibroblasts (P = 0.047) was noted between the 3 groups. Total cell density and glial cell density of the ERMs were strongly associated with poor final BCVA and BCVA improvement.

CONCLUSIONS

The present study provides new histopathologic information regarding the formation and progression of idiopathic ERM. Glial cell proliferation plays a predominant role in these processes. Epiretinal membranes with high cellularity and glial cell density may cause damage to the retina structure, resulting in poor postoperative visual outcomes. These findings provide additional evidence supporting early surgical intervention in patients with idiopathic ERM reported with visual disturbance.

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.

Macrophage-like cells are still detectable on the retinal surface after posterior vitreous detachment

The identity of vitreoretinal interface macrophage-like cells (MLCs) remains unknown and potential candidates include retinal microglia, perivascular macrophages, monocyte-derived macrophages, and/or vitreal hyalocytes. Since hyalocytes are detectable on the posterior vitreous surface after vitreous extraction in animals, we imaged patients with and without posterior vitreous detachment (PVD) to determine if hyalocytes are the principal MLC component. We performed repeated foveal-centered 3 × 3 mm OCT-A images from 21 eyes (11 no PVD and 10 PVD eyes). Images were registered, segmented, and averaged. The OCT slab from 0 to 3 microns above the internal limiting membrane was used to detect MLCs. We calculated MLC density and distribution in relation to the superficial vascular plexus for 3 vascular regions-on vessels, perivascular, and non-vascular. MLC density was 1.8-fold greater in the PVD group compared to the no PVD group (P = 0.04). MLCs in eyes with PVD were increased 1.9-fold on-vessel (P = 0.07), 1.9-fold in the perivascular region (P = 0.12), and 2.2-fold in non-vascular areas (P = 0.22). MLC density was not severely reduced after PVD, suggesting that the majority of MLCs are not vitreal hyalocytes. PVD status is an important parameter in future MLC studies.

Association of Epiretinal Membrane With Pseudoexfoliation Glaucoma and Long-term Factors Affecting Visual Function

PRCIS

Epiretinal membrane (ERM) tended to deteriorate more in pseudoexfoliation eyes with than without glaucoma. Incremental change in central macular thickness (CMT) induced by ERM deterioration affected longitudinal visual function in pseudoexfoliation glaucoma (PXG) eyes.

PURPOSE

The aim was to investigate longitudinal changes in the ERM and their association with glaucoma in patients with pseudoexfoliation syndrome (PXS) and to identify factors associated with the changes in ERM and visual field (VF).

PARTICIPANTS

One hundred two eyes with PXG and 32 eyes with nonglaucomatous pseudoexfoliation (ngPX) (mean 8.1±2.6 years of follow-up).

METHODS

Two observers independently assessed the presence and staging of ERM (stages 1, 2, and ≥3) on serial macular images of spectral-domain optical coherence tomography. Clinical characteristics were compared in eyes with ERM (+) and (-) in both groups. The relationship between putative factors and changes in ERM was determined using logistic regression analysis. Prognostic factors of VF worsening were assessed by Cox proportional hazard analysis.

RESULTS

Of the 102 eyes with PXG, 22 (21.6%) had an ERM at baseline; of the latter, 6 eyes deteriorated (all from stage 1 to 2) and 3 eyes with PXG developed new ERM during follow-up. Of the 32 ngPX eyes, 8 (25%) had an ERM at baseline, with none changing over time. The presence of glaucoma was marginally associated with ERM deterioration (odds ratio: 1.061, P =0.064). Incremental change in CMT was the only factor associated with VF progression (hazard ratio: 1.040, P =0.029) in PXG eyes.

CONCLUSIONS

ERM tended to deteriorate more in PXS eyes with than without glaucoma. Incremental change in CMT induced by ERM deterioration affected longitudinal visual function in PXG eyes.

Macrophage-like Cells Characterized by En Face Optical Coherence Tomography was Associated with Fluorescein Vascular Leakage in Behçet's Uveitis

PURPOSE

To investigate the features of macrophage-like cell (MLC) characterized by en face optical coherence tomography (OCT) in Behçet's uveitis (BU).

METHODS

The extent of fluorescein vascular leakage (FVL) was graded on a scale of 0-3 (0=none, 1=mild, 2=moderate, 3=severe) for the optic nerve head (ONH), macula and peripheral retina. The 3μm en face OCT slabs on inner limiting membrane of ONH or macular region was used to visualize the MLCs.

RESULTS

The MLC densities of BU group in ONH and macular region were significantly higher than the control group (both p<0.001). The ONH and macular MLC density were significantly higher in eyes with higher FVL grade and they were positively correlated with FVL score (all p<0.001).

CONCLUSION

MLC density was elevated in Behçet's uveitis and it may serve as a noninvasive indicator for the severity of fluorescein leakage and retinal inflammation in Behcet's uveitis.

Harnessing the Neuroprotective Behaviors of Müller Glia for Retinal Repair

Progressive and irreversible vision loss in mature and aging adults creates a health and economic burden, worldwide. Despite the advancements of many contemporary therapies to restore vision, few approaches have considered the innate benefits of gliosis, the endogenous processes of retinal repair that precede vision loss. Retinal gliosis is fundamentally driven by Müller glia (MG) and is characterized by three primary cellular mechanisms: hypertrophy, proliferation, and migration. In early stages of gliosis, these processes have neuroprotective potential to halt the progression of disease and encourage synaptic activity among neurons. Later stages, however, can lead to glial scarring, which is a hallmark of disease progression and blindness. As a result, the neuroprotective abilities of MG have remained incompletely explored and poorly integrated into current treatment regimens. Bioengineering studies of the intrinsic behaviors of MG hold promise to exploit glial reparative ability, while repressing neuro-disruptive MG responses. In particular, recent in vitro systems have become primary models to analyze individual gliotic processes and provide a stepping stone for in vivo strategies. This review highlights recent studies of MG gliosis seeking to harness MG neuroprotective ability for regeneration using contemporary biotechnologies. We emphasize the importance of studying gliosis as a reparative mechanism, rather than disregarding it as an unfortunate clinical prognosis in diseased retina.

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.

Vitreoretinal interface anomalies in patients with a history of toxoplasmosis retinochoroiditis

PURPOSE

To evaluate vitreoretinal interface anomalies over time in patients diagnosed with toxoplasmosis retinochoroiditis (TRC) and progression of the chronic disease.

STUDY DESIGN

Retrospective clinical study.

METHODS

The clinical records of 36 patients with TRC were studied retrospectively. All patients underwent standard ophthalmological examinations and optical coherence tomography (optical coherence tomography: OCT). Vitreoretinal interface changes and retinal layers in the macula and lesion area were evaluated.

RESULTS

The fovea was involved in 9 (25%) patients. OCT of the scar region showed retinal layer thinning and disorganization in all cases. Complete posterior vitreous detachment (PVD) was detected in 9 (25%) cases, incomplete PVD in 22 (61%) cases and no PVD in 5 (13.8%) cases. In 23 (63%) of the 36 patients with inactive TRC lesions, an epiretinal membrane (ERM) was detected by follow-up OCT, i.e., in 14 (60%) patients with incomplete PVD, 8 (34.7%) with complete PVD, and 1 (4%) with no PVD. Vitreoschisis was found in 5 of 22 patients with incomplete PVD; an ERM developed in 4 of these 5 patients. No ERM developed only in the macula, i.e., independent of the TRC scar region.

CONCLUSIONS

Vitreoretinal interface anomalies are common in patients diagnosed with TRC, including those with incomplete PVD. We observed no progression of vitreoretinal interface anomalies during the follow-up of patients diagnosed with TRC.

REVISED PREDICTIVE BIOMARKER FOR OCRIPLASMIN THERAPY IN VITREOMACULAR TRACTION DISORDERS

PURPOSE

To determine a statistically optimal limit of adhesion size in vitreomacular traction (VMT) syndrome for ocriplasmin treatment.

METHODS

In this retrospective, consecutive, interventional study, we included 106 patients treated with ocriplasmin injection because of VMT between July 2013 and January 2018. A univariate and multivariate risk analysis was performed with grouped factors and continuous factors. We used a receiver operating characteristic curve to measure the prognostic relevance of each continuous factor for therapy success and determined the statistically optimal cutoff value at which specificity and sensitivity are simultaneously maximized.

RESULTS

Among the grouped factors, only a phakic lens status showed a highly significant positive influence on the resolution of the VMT. For the continuous factors, only the adhesion diameter before injection was a good predictor of anatomical success. The statistically optimal threshold value for the adhesion size was calculated to be 480 µm. Eyes below this limit had a 6.84-fold better chance of VMT resolution compared with eyes with a larger adhesion diameter.

CONCLUSION

The threshold value of the VMT diameter for ocriplasmin therapy could be statistically defined as 480 µm and may thus be a new quantitative biomarker to predict treatment success.

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.

Cell composition at the vitreomacular interface in traumatic macular holes

Purpose

To describe characteristics of the vitreomacular interface (VMI) in traumatic macular holes (TMH) compared to idiopathic macular holes (IMH) using immunofluorescence and electron microscopy, and to correlate with clinical data.

Methods

For immunocytochemical and ultrastructural analyses, premacular tissue with internal limiting membrane (ILM) and epiretinal membrane (ERM) was harvested during vitrectomy from 5 eyes with TMH and 5 eyes with IMH. All specimens were processed as flat mounts for phase-contrast microscopy, interference and fluorescence microscopy, and transmission electron microscopy (TEM). Primary antibodies were used against microglial and macroglial cells. Clinical data was retrospectively evaluated.

Results

Surgically excised premacular tissue of eyes with TMH showed a less pronounced positive immunoreactivity for anti-glutamine synthetase, anti-vimentin and anti-IBA1 compared to eyes with IMH. Cell nuclei staining of the flat-mounted specimens as well as TEM presented a lower cell count in eyes with TMH compared to IMH. All detected cells were found on the vitreal side of the ILM. No collagen fibrils were seen in specimens of TMH. According to patients’ age, intraoperative data as well as spectral-domain optical coherence tomography (SD-OCT) analysis revealed an attached posterior vitreous in the majority of TMH cases (60%), whereas all eyes with IMH presented posterior vitreous detachment.

Conclusion

The vitreomacular interface in TMH and IMH shows significant differences. In TMH, glial cells are a rare finding on the vitreal side of the ILM.

Comparison of the Prevalence and Clinical Characteristics of Epiretinal Membrane in Pseudoexfoliation and Primary Open-angle Glaucoma

PURPOSE

The purpose of this study was to investigate and compare the prevalence and clinical characteristics of epiretinal membrane (ERM) in patients with pseudoexfoliation glaucoma (PXG) and primary open-angle glaucoma (POAG).

METHODS

In this retrospective observational study, 211 PXG eyes, 210 age-matched normal eyes, and 220 POAG eyes were included. The presence and staging of ERM (stage 1, 2, and 3 or greater) were independently assessed by 2 observers. Univariate and multivariate linear regression analyses were performed to assess the factors associated with visual field (VF) mean deviation (MD) in PXG eyes.

RESULTS

Among 211 PXG eyes, 40 (19.0%) had an ERM, while 4.1% of POAG and 2.4% of normal eyes had an ERM (P<0.001). Retinal nerve fiber layer thickness (69.4 vs. 70.4 μm, P=0.477) and VF MD (-7.7 vs. -10.4 dB, P=0.098) were not different between POAG and PXG eyes but macular thickness was greater (259.5 vs. 271.5 μm, P=0.006) in PXG eyes than in POAG. Both lower retinal nerve fiber layer thickness (β=0.337, P<0.001) and the presence of an ERM (β=-4.246, P=0.002) were independently associated with worse VF MD in PXG eyes.

CONCLUSIONS

The prevalence of ERM was significantly greater in PXG eyes than in age-matched normal or POAG eyes. The presence of ERM affected VF in PXG eyes.

Effectiveness of ocriplasmin in real-world settings: A systematic literature review, meta-analysis, and comparison with randomized trials

Purpose

Effectiveness of ocriplasmin for vitreomacular traction (VMT) varies depending on the presence of common ocular conditions and patient selection criteria. We carried out a systematic literature review and meta‐analysis of ocriplasmin studies conducted in real‐world settings (RWS) and compared outcomes with those from randomized controlled trials (RCTs).

Methods

We included prospective and retrospective studies from RWS documenting effectiveness of ocriplasmin in patients with VMT with or without MH, and RCTs of ocriplasmin versus control. Key end‐points were vitreomacular adhesion resolution (VMAR), nonsurgical MH closure, need for vitrectomy and safety. We conducted meta‐regression on pooled results to evaluate effects of baseline covariates and study design on outcomes.

Results

Thirty RWS (2402 patients) and 5 RCTs (737 patients) were included epiretinal membrane (ERM) and broad VMA were more prevalent in RCTs. Primary VMAR, vitrectomy and MH closure rates were comparable between RWS and RCTs. Rates of nsVMAR were significantly higher in RWS than RCTs (odds ratio 1.66; 95% confidence interval [CI]: 1.18–2.34). nsVMAR rates were inversely associated with ERM prevalence (odds ratio 0.20; 95% CI: 0.08–0.51). Compared with the recent OASIS trial, RWS reported a higher incidence of new/worsening subretinal fluid cases and less photophobia, photopsia, vitreous floaters, electroretinogram abnormalities and MH progression.

Conclusions

Ocriplasmin was significantly more effective in achieving nsVMAR in RWS than in RCTs. Lower ERM prevalence in RWS was the single significant explanatory variable for this difference. Conclusions on ocriplasmin safety in RWS are limited due to inconsistent reporting.

Increased risk of postsurgical macular edema in high stage idiopathic epiretinal membranes

PURPOSE

To assess the rate of occurrence and the risk factors of postsurgical macular edema (PSME) in eyes with idiopathic epiretinal membrane (iERM) or full-thickness macular hole (FTMH).

METHODS

Retrospective longitudinal analysis of all subjects scheduled for vitrectomy with or without combined cataract surgery over a 6-month period. Electronic medical charts and imaging data were analyzed preoperatively and at 1, 3 and 6 months after surgery.

RESULTS

From 101 patients diagnosed with iERM or FTMH, 71 patients were eligible for the study. Forty-nine eyes with iERM (69.0%) and 22 eyes with FTMH (31.0%) underwent vitrectomy either isolated (31.0%) or combined with cataract extraction (69.0%). The overall rate of PSME was 26.7%, without differences between the two groups (P = 0.9479). Combined cataract extraction did not affect the overall occurrence of PSME rate in both groups (P = 0.9255 in FTMH and P = 0.8658 in iERM). If grouped by stage, eyes with stage 4 iERM though disclosed an increased rate of PSME (57.1%) compared to lower (1 to 3) stages (14.3%, P = 0.0021), particularly when combined with cataract surgery (71.4% vs. 15.4% in stages ≤ 3, P = 0.0021). The PSME odds ratio for a stage 4 iERM is 8 (95% CI: 1.933-33.1; P = 0.0041) compared to stages 3 and below.

CONCLUSIONS

PSME remains a clinically relevant and frequent event after surgery for iERM and FTMH. Patients with stage 4 iERM have an 8-fold higher likelihood of developing PSME in a 6-month postsurgical period compared to iERM in 1-3 stages, especially when combined with cataract extraction.

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.

Functional and Morphological Results of Epiretinal Membrane Surgery in Idiopathic versus Diabetic Epiretinal Membranes

PURPOSE

Idiopathic and diabetic epiretinal membranes (ERM) are different in terms of pathophysiology, etiology, and macular morphology, and thus might respond to surgical treatment differently. We aimed to compare the surgical results of two groups.

METHODS

Retrospective case series study of 71 eyes of 66 patients who underwent pars plana vitrectomy (PPV) due to idiopathic or diabetic ERM with at least 1-year follow-up. Examinations were performed before, and 1, 3, 6, and 12 months after surgery. The average macular thicknesses in nine sectors described by the Early Treatment Diabetic Retinopathy Study (ETDRS) were measured with spectral-domain optical coherence tomography (OCT), and BCVA was evaluated. ERM recurrence rates were investigated.

RESULTS

In both idiopathic and diabetic groups, retinal thickness (RT) changes occurred as long as 12 months after vitrectomy surgery for ERM. However, in the idiopathic group, significant changes were mainly seen in the first 6 months, while in the diabetic group changes slowed considerably between the third and sixth months, but again accelerated (becoming significant) during the last 6 months.

CONCLUSIONS

According to the findings of this study, as compared to those with idiopathic ERM, diabetic patients would likely see continuing benefits from ERM surgery 6 to 12 months post surgery. The BCVA changes of the two groups were similar. ILM peeling decreased ERM recurrence in the idiopathic group but not in the diabetic group.

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.

In vitro generation of primary cultures of human hyalocytes

Purpose

A growing number of studies on animal models have demonstrated that some ocular diseases are the result of the interaction between hyalocytes and the ocular inflammatory setting. Endogenous and exogenous substances might alter the structure and behavior of hyalocytes that can contribute to the pathogenesis of some ocular diseases. Obtaining primary cultures of human hyalocytes could help understand the role of these cells in response to different treatments.

Methods

Hyalocytes were isolated from eyes of 54 patient volunteers subjected to vitrectomy for different clinical reasons. By testing different matrices and growth media, we reproducibly generated primary cultures of hyalocytes that we characterized morphologically and biologically, basally and upon treatment with several agents (basic fibroblast growth factor (bFGF), transforming growth factor beta 1 (TGF-β), platelet-derived growth factor subunit-BB (PDGF-BB), ascorbic acid, dexamethasone, and hydrogen peroxide).

Results

We were able to generate primary cultures from vitreous human samples, growing the cells on collagen-coated plates in Iscove's modified Dulbecco's medium supplemented with 10% fetal bovine serum; primary cells expressed the hyalocyte markers. Specific cytoskeletal modifications were observed upon treatment with bFGF, TGF-β, PDGF-BB, ascorbic acid, dexamethasone, and hydrogen peroxide. Only bFGF was able to promote cell growth and hyaluronic acid production.

Conclusions

We describe for the first time the generation and the characterization of primary cultures of human hyalocytes from living donors. Although human hyalocytes share some characteristics with animal hyalocytes, human hyalocytes have their own features typical of the species, confirming how important human experimental models are for investigating human pathologies and their treatments.

Visualization of different anatomical parts of the enucleated human eye using X-ray micro-CT imaging

Micro-CT visualization allows reconstruction of eye structures with the resolution of light microscopy and estimation of tissue densities. Moreover, this method excludes damaging procedures and allows further histological staining due to the similar steps in the beginning. We have shown the feasibility of the lab-based micro-CT machine usage for visualization of clinically important compartments of human eye such as trabecular outflow pathway, retina, iris and ciliary body after pre-treatment with iodine in ethanol. We also identified the challenges of applying this contrasting technique to lens, cornea, and retina and proposed alternative staining methods for these tissues. Thereby this work provides a starting point for other studies for imaging of human eyes in normal and pathological conditions using lab-based micro-CT systems.

Secondary epiretinal membrane after Ex-Press glaucoma filtration device implant

Purpose

To estimate the frequency of epiretinal membrane (ERM) in eyes with primary open-angle glaucoma (POAG) treated with Ex-Press shunt implant. Secondarily, we aimed to assess the role of concomitant cataract surgery and the impact of the ERM on central foveal thickness and macular volume.

Methods

In this prospective, consecutive, case-control study, we enrolled 54 patients affected by PAOG and scheduled for Ex-Press device implant with or without contemporary phacoemulsification. Contralateral eyes affected by POAG and receiving anti-glaucomatous eyedrops constituted the control group. Complete ophthalmologic evaluation and spectral-domain optical coherence tomography (OCT) were performed before and 1, 3 and 6 months after surgery.

Results

Twenty-six eyes received the Ex-Press implant alone, and 28 eyes underwent the combined procedure. Six months postoperatively, we observed 18 (33%) cases of ERM: 15 (28%) of cellophane macular reflex (CMR) and 3 (6%) of pre-macular fibrosis (PMF). In the control group, 9 (17%) eyes developed an ERM: 8 (15%) were CMR, and 1 (2%) was PMF. The frequency of ERM statistically differs between treated and contralateral eyes (P = 0.032, χ² test). The ERM frequency did not statically differ between eyes subjected to simple or combined surgery (P = 0.846, χ² test). Mean central foveal thickness and mean macular volume did not significantly differ between groups.

Conclusion

The Ex-Press glaucoma shunt may increase the risk of ERM onset regardless of the concomitant cataract surgery; however, most cases were cellophane macular reflex with limited functional and anatomical impact.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-020-05025-8.

CLINICAL CHARACTERISTICS, LONG-TERM SURGICAL OUTCOMES, AND PROGNOSTIC FACTORS OF EPIRETINAL MEMBRANE IN YOUNG PATIENTS

PURPOSE

To explore the clinical characteristics, long-term surgical outcomes, and prognostic factors for vision improvement in young patients with epiretinal membrane (ERM).

METHODS

A cohort of in-patients aged <40 years and underwent surgical removal of ERM were selected from medical records between January 2009 and December 2015. Data from pre- and postoperative examinations were analyzed for evaluation of surgical outcome.

RESULTS

A total of 142 eyes of 140 patients were included. Epiretinal membrane was secondary in 64.79% of eyes and inflammation was the most common secondary cause. Epiretinal membrane in young patients was characterized by severe proliferation and a tendency to center off-macula and for optic disk involvement. Ninety-three eyes of 91 patients were included in the surgical outcome analysis. Mean follow-up time was 28.95 months. The average vision improvement was 4.2 lines, with an ERM recurrence rate of 4.3%. Patients with idiopathic ERM attained better visual outcomes, whereas those with secondary ERM showed greater improvement. Preoperative visual acuity, the duration of symptoms, and patient sex were predictive factors for visual outcome.

CONCLUSION

Surgical removal of ERM improves visual acuity, and patients with greater preoperative visual acuity and a shorter duration of symptoms attain the best visual outcomes.

Evaluation of intraoperative slow-release dexamethasone implant combined with idiopathic epiretinal membrane removal

PURPOSE

To evaluate the efficacy of intraoperative slow-release dexamethasone implant (DEX) combined with removal of idiopathic epiretinal membrane (ERM).

METHODS

In this observational retrospective study, data of 40 patients with phakic eyes affected by idiopathic ERM were analysed. All patients underwent cataract phacoemulsification, 25-gauge (G) pars plana vitrectomy (PPV), ERM removal with DEX implant ("DEX YES" group, #20) or without DEX implant ("DEX NO" group, #20). We collected data on best-corrected visual acuity (BCVA) < 20/40 Snellen charts, central macular thickness (CMT) ≤ 400 μm (measured by SD-OCT) and integrity of sub-foveal ellipsoid/myoid zone. BCVA, CMT and intraocular pressure (IOP) were evaluated at baseline as well as 15, 30 and 90 days after surgery.

RESULTS

In the "DEX YES" group, statistically significant BCVA improvement was observed at 15, 30 and 90 days (p < 0.001), while in the "DEX NO" group, improvements were observed only at 30 and 90 days (p < 0.001). In both groups, CMT significantly decreased at each follow-up visit (p < 0.001), and no statistically significant increase of IOP was detected at each follow-up visit.

CONCLUSIONS

In this study, DEX accelerated the improvement of BCVA at 15 days after surgery. However, no evidence of further anatomical (CMT) and functional (BCVA) DEX effectiveness combined with removal of idiopathic ERM by 25-G PPV at 30 and 90 days follow-up was observed.

The role of simple inflammatory blood parameters in idiopathic epiretinal membrane patients

AIM

To evaluate the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in idiopathic epiretinal membrane (IERM) patients, and their relations with visual acuity.

METHOD

Fifty-seven IERM and 51 control patients were included. All patients underwent comprehensive ophthalmological examination and complete blood count tests, and NLR and PLR values were calculated. Patients with IERM were compared with the control group, and associations with visual prognosis were evaluated. These ratios' cut-off values for IERM were also calculated RESULTS: NLR values were statistically significantly higher in the IERM group than in the control group (p = 0.001). No significant difference was observed between the IERM and control groups in terms of PLR (p = 0.43). No significant correlation was determined between visual acuity and NLR or PLR (r = 0.05, p = 0.66; and r = 0.18, p = 0.16, respectively). The cut-off value for NLR was 1.91.

CONCLUSION

Patients with IERM showed significantly increased NLR compared to control subjects suggesting that IERM patients may be prone to have high NLR values.

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.

Epiretinal Membrane Detection at the Ophthalmologist Level using Deep Learning of Optical Coherence Tomography

Purpose: Previous deep learning studies on optical coherence tomography (OCT) mainly focused on diabetic retinopathy and age-related macular degeneration. We proposed a deep learning model that can identify epiretinal membrane (ERM) in OCT with ophthalmologist-level performance. Design: Cross-sectional study. Participants: A total of 3,618 central fovea cross section OCT images from 1,475 eyes of 964 patients. Methods: We retrospectively collected 7,652 OCT images from 1,197 patients. From these images, 2,171 were normal and 1,447 were ERM OCT. A total of 3,141 OCT images was used as training dataset and 477 images as testing dataset. DL algorithm was used to train the interpretation model. Diagnostic results by four board-certified non-retinal specialized ophthalmologists on the testing dataset were compared with those generated by the DL model. Main Outcome Measures: We calculated for the derived DL model the following characteristics: sensitivity, specificity, F1 score and area under curve (AUC) of the receiver operating characteristic (ROC) curve. These were calculated according to the gold standard results which were parallel diagnoses of the retinal specialist. Performance of the DL model was finally compared with that of non-retinal specialized ophthalmologists. Results: Regarding the diagnosis of ERM in OCT images, the trained DL model had the following characteristics in performance: sensitivity: 98.7%, specificity: 98.0%, and F1 score: 0.945. The accuracy on the training dataset was 99.7% (95% CI: 99.4 - 99.9%), and for the testing dataset, diagnostic accuracy was 98.1% (95% CI: 96.5 - 99.1%). AUC of the ROC curve was 0.999. The DL model slightly outperformed the average non-retinal specialized ophthalmologists. Conclusions: An ophthalmologist-level DL model was built here to accurately identify ERM in OCT images. The performance of the model was slightly better than the average non-retinal specialized ophthalmologists. The derived model may play a role to assist clinicians to promote the efficiency and safety of healthcare in the future.

Deformation analysis of lipid membranes subjected to general forms of intra-membrane viscous flow and interactions with an elliptical-cross-section substrate

We study the morphology of lipid membranes subjected to intra-membrane viscous flows and interactions with elliptical cylinder substrates. From the non-linear theory of elastic surfaces, a linearized shape equation and admissible boundary conditions are formulated in elliptical coordinates via the Monge representation of a surface. In particular, the intra-membrane viscosity terms are linearized and mapped into elliptic coordinates in order to accommodate more general forms of viscous flow. The assimilated viscous flow is characterized by potential functions which satisfies the continuity condition. A complete solution in terms of Mathieu function is then obtained within the prescription of incremental deformations superposed on large. The results describe smooth morphological transitions over the domain of interest and, more importantly, predicts wrinkle formations in the presence of intra-membrane viscous flow in the surface. Lastly, the obtained solution accommodates the results from the circular cases in the limit of vanishing eccentricity and intra-membrane viscous flow.

A Review of Last Decade Developments on Epiretinal Membrane Pathogenesis

Epiretinal membrane (ERM) is a pathologic tissue that develops at the vitreoretinal interface. ERM is responsible for pathological changes of vision with varying degrees of clinical significance. It is either idiopathic or secondary to a wide variety of diseases such as proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR). A great variation in the prevalence of idiopathic ERM among different ethnic groups proposed that genetic and lifestyle factors may play a role in ERM occurrence. Histopathological studies demonstrate that various cell types including retinal pigment epithelium (RPE) cells, fibrocytes, fibrous astrocytes, myofibroblast-like cells, glial cells, endothelial cells (ECs) and macrophages, as well as trophic and transcription factors, including transforming growth factor (TGF), vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) etc., are directly or indirectly involved in the pathogenesis of idiopathic or secondary ERMs. These processes are driven (on the last count) by more than 50 genes, such as Tumor Necrosis Factor (TNF), CCL2 (chemokine (C-C motif) ligand )), Metastasis Associated Lung Adenocarcinoma Transcript 1 )MALAT1(, transforming growth factor (TGF)-β1, TGF-β2, Interleukin-6 (IL-6), IL-10, VEGF and glial fibrillary acidic protein (GFAP), some of which have been studied more intensely than others. The present paper tried to summarize, highlight and cross-correlate the major findings made in the last decade on the function of these genes and their association with different types of cells, genes and gene expression products in the ERM formation.