Prognostic factors of idiopathic epiretinal membrane surgery and evolution of alterations of the central cone bouquet

Idiopathic Epiretinal Membranes - Pathophysiology, Classifications and OCT-Biomarkers

Epiretinal membranes (ERMs) are a common finding in patients with increasing age. Diagnosis and treatment of ERMs have changed dramatically in recent years due to technological advances in ophthalmological care. In recent years, tomographic imaging has allowed for accurate visualization of ERMs and contributed to the growing understanding of the pathophysiology of this condition. The literature review conducted here summarizes recent innovations in diagnosis, classification, and treatment of idiopathic ERMs and specifically addresses novel optical coherence tomography (OCT) biomarkers that allow for the generation of prognoses regarding the clinical postoperative outcome.

Short-term-outcomes of idiopathic epiretinal membranes treated with pars-plana-vitrectomy - examination of visual function and OCT-morphology

BACKGROUND

Epiretinal membranes (ERM) represent one of the most common findings in retinal examination. Structural changes of the retinal layers in patients with ERM can be visualized and classified using OCT. The purpose of this study is to evaluate structural and functional changes related to surgical treatment of ERM.

METHODS

Monocentric retrospective analysis of 92 patients who underwent 23-gauge-pars plana vitrectomy (ppV) combined with cataract surgery for idiopathic ERM from 2015 to 2020. Visual acuity was determined directly preoperatively, at four weeks and three months postoperatively. Disease stage and tomographic biomarkers related to ERM were assessed in OCT imaging.

RESULTS

92 eyes of 92 patients were included. At the time of surgery, the mean patient age was 71 years. Visual acuity improved significantly by 2 lines postoperatively, on average from LogMar 0.4 to 0.2 (p < 0.001). Disease stage regressed from stage 3 to stage 2 postoperatively (p < 0.001). No patient had stage 4 postoperatively (n = 0). In the presence of preoperative intraretinal fluid, mean retinal thickness was 488 μm and decreased to 392 μm postoperatively (n = 32; p < 0.001). Preoperative presence of a Cotton Ball Sign (n = 30) was associated with better visual acuity (p = 0.009). This was also visible in patients with preoperative vitreomacular traction syndrome (p < 0.001). The presence of preoperative intraretinal fluid showed a tendency towards better disease staging after surgery (p = 0.080).

CONCLUSION

Surgery was able to achieve visual improvement and morphological regression of the preoperative OCT findings related to ERM. ppV led to a reduction in retinal thickness and disease stage. The presence of the Cotton Ball Sign and vitreomacular traction was associated with better visual acuity in the follow-up period. In our cohort the preoperative presence of intraretinal fluid showed a tendency for better postoperative disease staging.

Associations between macular retinal vasculature and severity of idiopathic epiretinal membrane

BACKGROUND

To demonstrate the associations between the morphology of macular retinal vasculature and disease severity of idiopathic epiretinal membrane (ERM).

METHODS

Macular structures were assessed using optical coherence tomography (OCT), and were classified as "with pseudohole" or "without pseudohole". The 3 × 3 mm macular OCT angiography images were analyzed using the Fiji software to obtain the vessel density, skeleton density, average vessel diameter, vessel tortuosity, fractal dimension, and foveal avascular zone (FAZ)-related parameters. The correlations between these parameters and ERM grading as well as visual acuity were analyzed.

RESULTS

For ERM with or without a pseudohole, increased average vessel diameter, decreased skeleton density, and decreased vessel tortuosity were all associated with inner retinal folding and thickened inner nuclear layer, indicating more severe ERM. In 191 eyes without a pseudohole, the average vessel diameter increased, fractal dimension decreased and vessel tortuosity decreased with increasing ERM severity. The FAZ was not associated with ERM severity. Decreased skeleton density (r = -0.37), vessel tortuosity (r = -0.35), and increased average vessel diameter (r = 0.42) were correlated with worse visual acuity (All P < 0.001). In 58 eyes with pseudoholes, a larger FAZ was associated with a smaller average vessel diameter (r = -0.43, P = 0.015), higher skeleton density (r = 0.49, P < 0.001), and vessel tortuosity (r = 0.32, P = 0.015). However, none of the retinal vasculature parameters correlated with visual acuity and central foveal thickness.

CONCLUSION

Increased average vessel diameter, decreased skeleton density, decreased fractal dimension and decreased vessel tortuosity were good indicators of ERM severity and associated visual impairment.

A useful technique of starting internal limiting membrane peeling from the edge of the internal limiting membrane defect in epiretinal membrane surgery

Clinicians should be aware that internal limiting membrane (ILM) defects may occur concurrently with epiretinal membrane, and starting ILM peeling at the ILM defect margin may be useful in such cases.

Abstract

We describe a useful surgical technique for the treatment of idiopathic epiretinal membrane with concurrent internal limiting membrane (ILM) defect, in which ILM peeling was started from the ILM defect margin. A dissociated optic nerve fiber layer-like appearance on fundus examination and optical coherence tomography may suggest an ILM defect.

Choroidal morphologic and vascular features in patients with unilateral idiopathic epiretinal membranes: An optical coherence tomography analysis integrated with assessment of retinal layers

Introduction

Integrated analysis of retinal and choroidal morphologic and vascular features is urgently needed to examine whether and how these two elements interact with each other, thus contributing to visual impairment in patients with idiopathic epiretinal membranes (iERMs).

Methods

An observational retrospective study consisting of 181 patients diagnosed with unilateral iERM between August 2019 and July 2022 was carried out at Peking University Third Hospital. All patients underwent a standardized set of ophthalmologic examinations, including EDI-OCT and OCTA scanning, and were subsequently categorized into four stages according to current classification schemes based on their OCT findings. Altogether, 15 qualitative and quantitative parameters of both the retina (full-layer, inner and outer layers) and choroid were identified.

Results

The results revealed variations in the choroidal vascularity index (CVI) among different stages of iERMs (p < 0.001) for the first time. Distributions of retinal parameters across four stages of iERMs were validated. Correlation analysis between choroidal and retinal parameters showed that the CVI was associated with both inner and outer retinal morphologic biomarkers. Functional damage to retinal integrity was determined to be a strong contributor to visual acuity reduction in iERMs.

Discussion

This study complemented our present understanding of posterior segment structural and vascular alterations in iERMs.

Influence of Preoperative Foveal Layers’ Thickness on Visual Function and Macular Morphology by Phacovitrectomy for Epiretinal Membrane

Background. The aim of this retrospective study with short, differently dispersed follow-up is to record the relationships between the pathologies of the individual foveal layers, measured by spectral domain optical coherence tomography (SD-OCT), and to investigate their influence on pre- and postoperative best-corrected decimal far visual acuity (BCVA) by phacovitrectomy for epiretinal membrane (ERM) in comorbidity with cataract. Patients and Methods. 208 eyes of 173 patients with symptomatic idiopathic ERM and moderate cataract were included. Results. In all OCT morphological stages of ERM, as well as in their combination with macular lamellar hole (MLH) and vitreomacular traction (VMT), a significant difference in the thickness of the individual fovea layers was found. In addition, the entire fovea thickening led to the proportional thickening of the individual fovea layers ( $p<0.001$ ). The larger the central foveolar (CFT, R2 = −0.238, $p=0.002$ ), maximum foveal (MFT, R2 = −0.267, $p=0.001$ ), and ONL thickness (R2 = −0.16, $p=0.044$ ) were preoperatively, the worse the initial visual acuity was at all OCT stages of ERM. This was even more significant in the presence of a tractive component in the case of MLH or VMT ( $p<0.001$ ). In ERM without a traction component, only ONL thickening led to significant postoperative visual acuity reduction (R2 = −0.163, $p=0.047$ ). The foveolar retinal thickening (CFT and MFT) of the pure ERM is directly associated with distortion of the retinal layers (R2 = 0.292, $p<0.001$ and R2 = 0.287, $p<0.001$ ) as well as with separation of the ERM (R2 = 0.168, $p=0.034$ and R2 = 0.187, $p=0.018$ ). When ERM was combined with tractive component, CFT, ONL, and INL thickness correlated (positively) with the integrity of ellipsoid zone (R2 = 0.342, $p<0.05$ ) and external limiting membrane (R2 = 0.548, $p<0.001$ ). Conclusions. ONL thickening in ERM without a tractive component serves as a limited prognostic factor of postoperative visual acuity decrease. The preoperative BCVA in the groups of ERM with traction component showed significant correlation with CFT as well as with the thickness of individual foveal layers. VMT in ERM correlates with the disintegration of the ellipsoid zone.

Preoperative ocular coherence tomographic prognosticators of visual acuity after idiopathic epiretinal membrane surgery

PURPOSE

To provide a current review of the evidence for the utility of preoperative ocular coherence tomography (OCT) parameters in prognosticating postoperative visual acuity and visual improvement after idiopathic epiretinal membrane surgery. To determine which OCT bio-markers are most useful in this regard and where future studies may apply more emphasis.

METHODS

An extensive search of the PubMed database was performed for studies investigating this relationship. Key search terms included: idiopathic, epiretinal membrane, surgery, peel, vitrectomy, vision, outcomes, visual acuity, ocular coherence tomography, central foveal thickness, foveal contour, foveal morphology, ectopic inner foveal layers, inner retinal layers, inner retinal irregularity index, outer retinal layers, ellipsoid zone, interdigitation zone, photoreceptor outer segment length, central bouquet abnormality, staging, choroidoscleral irregularity, ganglion cell and nerve fibre layers, inner and outer plexiform layers, inner and outer nuclear layers. Forty-nine peer-reviewed articles were included in this review. These consisted of 28 retrospective studies [1-3,13,16-18,20,23-29,32-36,38,40,42-47], 17 prospective studies[6-12,14,19,21,22,30,31,37,41,48,49], 2 reviews [4,39] and 2 systematic reviews [5,15].

CONCLUSION

The weight of literary evidence seems to support photoreceptor integrity as the most consistent OCT marker of better postoperative visual acuity. This includes analysis of ellipsoid and interdigitation zones as well as photoreceptor outer segment length. However, the newer OCT staging system proposed by Govetto et al. (2017) fulfils a need for a clinically useful and evidence-based OCT classification. It may be the way forward in prognosticating ERM surgical outcomes by preoperative stratification. There is insufficient evidence to suggest the other discussed parameters in this review as useful prognosticators of postoperative visual acuity.