Inner-Retinal Irregularity Index Predicts Postoperative Visual Prognosis in Idiopathic Epiretinal Membrane

Evaluation of combined epiretinal membrane removal with intravitreal triamcinolone injection utilizing ectopic inner foveal layer staging scheme

OBJECTIVE

To investigate the macular morphological and visual outcomes of combined idiopathic epiretinal membrane (iERM) removal with triamcinolone acetonide (TA) injection based on consideration of the ectopic inner foveal layer (EIFL) staging scheme.

METHODS

Retrospective case-control study. The clinical data of 84 eyes of 84 patients who underwent vitrectomy for iERM between 2018 and 2022 were reviewed. The enrolled subjects were divided into the TA and non-TA groups. Fifty-one eyes received intravitreal TA injection following vitrectomy and ERM peeling (TA group), and 33 were only treated by standard vitrectomy and ERM peeling (non-TA group). Preoperative and postoperative EIFL stages, central foveal thickness (CFT), and best-corrected visual acuity (BCVA) were compared between both groups.

RESULTS

After a mean follow-up of 7.69 ± 3.68 months, both groups exhibited significant improvement in EIFL stages (P < 0.01), with no discernible advantage observed in the TA group. The TA and non-TA groups demonstrated improvement in the EIFL stages in 56.86 and 63.64% of eyes, respectively (P = 0.43). The CFT and BCVA significantly improved in both groups at the final visit (P < 0.01). However, CFT in the non-TA group displayed a more significant reduction during the follow-up (P < 0.03). Subgroup analysis revealed no significant differences in postoperative CFT and BCVA between the two groups in cases with or without continuous EIFL (P > 0.10).

CONCLUSION

Our findings indicate that combined intravitreal TA injection following ERM removal conferred no significant benefits in alleviating macular thickening or improving visual acuity in iERM.

Comparison of Functional, Structural, and Microvascular Features in Different Stages of Idiopathic Epiretinal Membrane

Background: Idiopathic epiretinal membrane (ERM) often leads to visual symptoms such as metamorphopsia and decreased central vision. This study aimed to evaluate functional, structural, and microvascular characteristics in patients with different stages of idiopathic ERM who were candidates for surgery, with a focus on identifying potential indicators for surgical timing. Methods: A retrospective cohort study was conducted on consecutive patients with unilateral idiopathic ERM who were candidates for surgery. Patients underwent comprehensive ophthalmological assessments, including OCT grading, reading performance evaluation, and OCT angiography. Data analysis included comparisons between different ERM stages for functional, structural, and microvascular parameters. Results: A total of 44 eyes were included, classified into four ERM stages according to the Govetto grading system. Functional parameters, including distance and near visual acuity, worsened significantly with higher ERM stages, particularly in the transition from Stage 3 to Stage 4. Structural assessments revealed significant increases in central macular thickness (CMT) from Stage 3 to Stage 4. No significant differences were observed in microvascular features across different ERM stages. Conclusions: This study highlights the significant functional and anatomical impact of OCT staging in idiopathic ERM, particularly during the transition from Stage 3 to Stage 4, characterized by notable reductions in visual acuity and increases in CMT. These findings underscore the importance of considering both functional and structural parameters in surgical decision-making for ERM management. However, further research with larger cohorts is needed to confirm these observations and inform clinical practice.

Quantitative evaluation of metamorphopsia with M-CHARTS™ and evaluation of retinal morphologic changes by optical coherence tomography before and after pars plana vitrectomy in patients with idiopathic epiretinal membrane

PURPOSE

We aimed to quantitatively evaluate metamorphopsia pre- and postoperatively in patients with idiopathic epiretinal membrane(iERM) using M-CHARTS™ and to evaluate the relationship between morphological changes in retinal layers on optical coherence tomography (OCT) and metamorphopsia scores.

MATERIALS AND METHODS

This prospective study included 42 patients followed in Akdeniz University Hospital Ophthalmology Clinic diagnosed with iERM by fundus examination and OCT between 2020-2022. Detailed ophthalmologic findings, visual acuities, metamorphopsia scores, and OCT parameters of all patients were recorded. The relationship between pre- and postoperative visual acuity, metamorphopsia scores and OCT parameters was investigated. Changes in OCT parameters were compared by evaluating patients with stable or increasing metamorphopsia scores as one group (group1) and patients with decreasing metamorphopsia scores as the other group (group 2).

RESULTS

In "group 2", preoperative Ganglion Cell Layer+Inner Plexiform Layer (Central) (GCL+IPL (C)) was significantly (P: 0.028) higher than in "group 1".

CONCLUSION

A statistically significant preoperative thickness difference in the OCT parameters of the GCL+IPL (C) layer was associated with the quantitative metamorphopsia complaints of the patients. The thickness of the preoperative GCL+IPL (C) layer can be considered an important indicator of symptoms of metamorphopsia determining functional success after surgery.

Optical coherence tomography parameters as prognostic factors for stereopsis after vitrectomy for unilateral epiretinal membrane: a cohort study

This retrospective cohort study explored the relationship between monocular and interocular optical coherence tomography (OCT) parameters and stereopsis in 56 patients undergoing pars plana vitrectomy (PPV) for unilateral idiopathic epiretinal membrane (IERM). IERM impairs visual functions, with symptoms ranging from asymptomatic to severe impairment. Despite established surgical interventions, including PPV with membrane peeling, the impact on advanced three-dimensional visual functions such as stereopsis remains inadequately investigated. All subjects were assessed for stereopsis, visual acuity, and metamorphopsia, alongside spectral domain OCT parameters. These visual functions significantly improved 3-month postoperatively. Central retinal thickness at the fovea, parafovea, and perifovea (CFT, CRT-3 mm, and CRT-6 mm), ectopic inner foveal layer thickness, and retinal layer thickness notably decreased 1 week to 3 months after surgery. The interocular difference in OCT parameters between bilateral eyes was included as a parameter. Baseline CRT-3 mm difference and inner nuclear layer (INL) thickness were independently correlated with postoperative stereopsis on the Titmus Stereo Test, while baseline CRT-6 mm difference and INL thickness were independently related to stereopsis on the TNO stereotest. This study highlights the substantial enhancement in stereopsis post-IERM surgery, with both interocular and monocular OCT parameters independently influencing postoperative stereopsis. These findings underscore the importance of retinal microstructures in assessing and predicting stereopsis in IERM patients after vitrectomy.

Assessment of area and structural irregularity of retinal layers in diabetic retinopathy using machine learning and image processing techniques

Diabetes retinopathy prevention necessitates early detection, monitoring, and treatment. Non-invasive optical coherence tomography (OCT) shows structural changes in the retinal layer. OCT image evaluation necessitates retinal layer segmentation. The ability of our automated retinal layer segmentation to distinguish between normal, non-proliferative (NPDR), and proliferative diabetic retinopathy (PDR) was investigated in this study using quantifiable biomarkers such as retina layer smoothness index (SI) and area (S) in horizontal and vertical OCT images for each zone (fovea, superior, inferior, nasal, and temporal). This research includes 84 eyes from 57 individuals. The study shows a significant difference in the Area (S) of inner nuclear layer (INL) and outer nuclear layer (ONL) in the horizontal foveal zone across the three groups (p < 0.001). In the horizontal scan, there is a significant difference in the smoothness index (SI) of the inner plexiform layer (IPL) and the upper border of the outer plexiform layer (OPL) among three groups (p < 0.05). There is also a significant difference in the area (S) of the OPL in the foveal zone among the three groups (p = 0.003). The area (S) of the INL in the foveal region of horizontal slabs performed best for distinguishing diabetic patients (NPDR and PDR) from normal individuals, with an accuracy of 87.6%. The smoothness index (SI) of IPL in the nasal zone of horizontal foveal slabs was the most accurate at 97.2% in distinguishing PDR from NPDR. The smoothness index of the top border of the OPL in the nasal zone of horizontal slabs was 84.1% accurate in distinguishing NPDR from PDR. Smoothness index of IPL in the temporal zone of horizontal slabs was 89.8% accurate in identifying NPDR from PDR patients. In conclusion, optical coherence tomography can assess the smoothness index and irregularity of the inner and outer plexiform layers, particularly in the nasal and temporal regions of horizontal foveal slabs, to distinguish non-proliferative from proliferative diabetic retinopathy. The evolution of diabetic retinopathy throughout severity levels and its effects on retinal layer irregularity need more study.

Impact of intravitreal triamcinolone injection following epiretinal membrane peeling on ectopic inner foveal layer classification

PURPOSE

This study aimed to evaluate the impact of intravitreal triamcinolone acetonide (TA) administration after peeling of idiopathic epiretinal membranes (iERM) on both anatomical and visual outcomes, utilizing the ectopic inner foveal layer (EIFL) staging scheme.

METHODS

In this retrospective case-control study, we analyzed 43 eyes from 43 patients diagnosed with iERM between June 2019 and December 2021. All participants were categorized into the TA or control groups based on administering intravitreal TA injection following ERM peeling. We thoroughly reviewed the clinical data, including the preoperative and postoperative best-corrected visual acuity (BCVA), central foveal thickness (CFT), and macular cube volume (VOL), with ERM stages classified according to the EIFL staging scheme.

RESULTS

The study enrolled 22 eyes in the TA and 21 in the control groups. Following a mean follow-up period of 11.07 ± 2.02 months, noteworthy improvements in EIFL stages were observed in both cohorts (p < 0.01), but without significant distinctions between groups. In the TA group, 63.64% of eyes demonstrated improvements in EIFL stages, while the control group exhibited 76.19% (p = 0.37). At the final visit, both groups experienced a noteworthy reduction in the postoperative CFT and VOL (p < 0.05), coupled with significant improvement in BCVA (p < 0.01). No substantial differences appeared between the two groups concerning BCVA, CFT, and VOL (all p > 0.05).

CONCLUSIONS

Our study suggested that concurrent intravitreal TA injection following ERM removal did not provide additional benefits regarding anatomical and visual improvement in iERM cases classified as Stages 2 and 3.

Idiopathic epiretinal membranes: postoperative changes in morphology

OBJECTIVE

To describe retinal morphology in idiopathic epiretinal membranes (ERMs) and to evaluate factors influencing function at different postoperative times up to 24 months.

DESIGN

Retrospective study.

PARTICIPANTS

A total of 121 eyes of 117 patients followed with spectral-domain optical coherence tomography for 24 months.

METHODS

The following details were analyzed: type of ERM, central retinal thickness, and status of all retina layers in the fovea, especially the outer nuclear layer (ONL) and photoreceptor layer. We evaluated the presence of disorganization of retinal inner layers (DRIL), ectopic inner foveal layer (EIFL), elevation (stretching) of the ONL, cotton ball sign, and type connection between the retina and ERMs (complete adherence or multiple junction spots).

RESULTS

The percentage of DRIL, EIFL, and stretched ONL decreased. Several factors negatively influenced visual acuity during the early postoperative controls: age, interdigitation zone defects; presence of cotton ball sign, DRIL, EIFL, and stretched ONL; and strong adhesion of the ERMs to the retina. Twenty-four months after surgery, only DRIL and strong adhesion between ERMs and the retina remained statistically significant.

CONCLUSIONS

Younger patients (p < 0.001) and patients without DRIL (p < 0.001) experienced a faster recovery of function. The length of follow-up was associated with a decrease of factors influencing the final outcome. After 24 months, only the presence of DRIL and strong adhesion between the ERMs and the retina were significant. Assuming that DRIL appears in more advanced stages when compared with EIFL, this allows us to suggest that earlier surgery might be of more benefit in idiopathic ERMs.

Deep learning-based prediction of the retinal structural alterations after epiretinal membrane surgery

To generate and evaluate synthesized postoperative OCT images of epiretinal membrane (ERM) based on preoperative OCT images using deep learning methodology. This study included a total 500 pairs of preoperative and postoperative optical coherence tomography (OCT) images for training a neural network. 60 preoperative OCT images were used to test the neural networks performance, and the corresponding postoperative OCT images were used to evaluate the synthesized images in terms of structural similarity index measure (SSIM). The SSIM was used to quantify how similar the synthesized postoperative OCT image was to the actual postoperative OCT image. The Pix2Pix GAN model was used to generate synthesized postoperative OCT images. Total 60 synthesized OCT images were generated with training values at 800 epochs. The mean SSIM of synthesized postoperative OCT to the actual postoperative OCT was 0.913. Pix2Pix GAN model has a possibility to generate predictive postoperative OCT images following ERM removal surgery.

Correlation between Severity of Idiopathic Epiretinal Membrane and Irvine-Gass Syndrome

A higher risk of pseudophakic cystoid macular edema (PCME) has been reported in patients with preoperative idiopathic epiretinal membrane (ERM); however, whether the formation of PCME depends on the grade of ERM has not been well established. We conducted a retrospective case-control study of 87 eyes of 78 patients who were preoperatively diagnosed with idiopathic ERM and had undergone cataract surgery. Patients were divided into two groups: PCME and non-PCME groups. After cataract surgery, the ERM status was graded using the Gass and Govetto classifications. Both the central macular thickness (CMT) and ERM grade increased after surgery, and higher preoperative CMT and ERM grades were found in the PCME group. The association between higher-grade ERM and the development of PCME was significant in the Govetto classification (grade 2, odds ratio (OR): 3.13; grade 3, OR: 3.93; and grade 4, OR: 16.07). The study results indicate that close attention should be given to patients with ERM with the presence of an ectopic inner foveal layer before cataract surgery.

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.

Multimodal Assessment of the Prognostic Role of Ectopic Inner Foveal Layers on Epiretinal Membrane Surgery

BACKGROUND

To perform a multimodal assessment of the ectopic inner foveal layers' (EIFL) prognostic role on idiopathic epiretinal membrane (ERM) surgery.

METHODS

We retrospectively followed-up for 12 months 27 patients who underwent ERM surgery and stratified them based on EIFL presence (group 1) or absence (group 2) at baseline. Central Retinal Thickness (CRT) and best-corrected visual acuity (BCVA) were compared pre- and post-operatively at 1, 4 and 12 months, whereas fixation stability (FS), macular sensitivity (MS) and multifocal electroretinogram (mfERG) responses were confronted at baseline and 12 months.

RESULTS

In group 1, BCVA improved at 4 and 12 months (MD = 0.14 (SE = 0.04); MD = 0.13 (SE = 0.05), respectively) as well as in group 2 (MD = 0.31 (SE = 0.07); MD = 0.41 (SE = 0.08), respectively). CRT did not change in group 1, whereas it decreased in group 2 at 4 and 12 months (MD = -73.13; SE = 23.56; MD = -76.20; SE = 23.56). MS showed no changes in both groups after surgery. FS did not change in group 1, whereas group 2 improved FS 2° (+8.91 ± 13.97) and FS 4° (+4.33 ± 3.84). MfERG P1 wave did not change in group 1, while in group 2 αP1-2, αP1-3 and αP1-4 improved postoperatively (27.97 ± 27.62; 12.51 ± 17.36; 10.49 ± 17.19, respectively).

CONCLUSIONS

Multimodal assessment confirmed that EIFL negatively affected ERM surgery outcomes.

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.

PREDICTING VISUAL OUTCOME AFTER SURGERY IN PATIENTS WITH IDIOPATHIC EPIRETINAL MEMBRANE USING A NOVEL CONVOLUTIONAL NEURAL NETWORK

PURPOSE

To develop a deep convolutional neural network that enables the prediction of postoperative visual outcomes after epiretinal membrane surgery based on preoperative optical coherence tomography images and clinical parameters to refine surgical decision making.

METHODS

A total of 529 patients with idiopathic epiretinal membrane who underwent standard vitrectomy with epiretinal membrane peeling surgery by two surgeons between January 1, 2014, and June 1, 2020, were enrolled. The newly developed Heterogeneous Data Fusion Net was introduced to predict postoperative visual acuity outcomes (improvement ≥2 lines in Snellen chart) 12 months after surgery based on preoperative cross-sectional optical coherence tomography images and clinical factors, including age, sex, and preoperative visual acuity. The predictive accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve of the convolutional neural network model were evaluated.

RESULTS

The developed model demonstrated an overall accuracy for visual outcome prediction of 88.68% (95% CI, 79.0%-95.7%) with an area under the receiver operating characteristic curve of 97.8% (95% CI, 86.8%-98.0%), sensitivity of 87.0% (95% CI, 67.9%-95.5%), specificity of 92.9% (95% CI, 77.4%-98.0%), precision of 0.909, recall of 0.870, and F1 score of 0.889. The heatmaps identified the critical area for prediction as the ellipsoid zone of photoreceptors and the superficial retina, which was subjected to tangential traction of the proliferative membrane.

CONCLUSION

The novel Heterogeneous Data Fusion Net demonstrated high accuracy in the automated prediction of visual outcomes after weighing and leveraging multiple clinical parameters, including optical coherence tomography images. This approach may be helpful in establishing personalized therapeutic strategies for epiretinal membrane management.

Effects of disorganization of retinal inner layers for Idiopathic epiretinal membrane surgery: the surgical status and prognosis

BACKGROUND

To compare the surgical status in idiopathic epiretinal membrane (IERM) patients with or without disorganization of retinal inner layers (DRIL) and to correlate with optical coherence tomography angiography (OCTA) and clinical data.

METHODS

In 74 eyes from 74 patients with IERM treated by surgery with 12-month follow-up. According to the superficial hemorrhage, the patients were divided into group A (no macular bleeding), group B (macular parafoveal bleeding) and group C (macular foveal bleeding). Optical coherence tomography (OCT) were evaluated for presence of DRIL,central retina thickness and integrity of the inner/outer segment layer recorded at baseline and at 1, 3, 6, and 12 months postoperatively and best-corrected visual acuity (BCVA) was recorded simultaneously. OCTA was conducted at 12 months postoperatively. Main outcome measures is correlation between DRIL and superficial hemorrhage in membrane peeling,and BCVA and OCTA outcomes postoperatively.

RESULTS

The rate of DRIL and BCVA had statistically significant differences between the three groups at the time points(baseline and 1, 3, 6, and 12 months after surgery), respectively (P < 0.001 for all). FD-300 value (P = 0.001)and DCP in all parafoveal regions (superior: P = 0.001; inferior: P = 0.002;Nasal: P = 0.014;Tempo: P = 0.004) in eyes with DRIL were lower than those without DRIL.There was a linear regression relationship between FD-300 and postoperative BCVA (P = 0.011).

CONCLUSION

IERM Patients with DRIL have more intraoperative adverse events and limited benefits from surgery which should be considered in the decision whether to perform mebrane peeling.OCT-A provides more detailed vascular information that extends our understanding of persistent DRIL.

Automated assessment of the smoothness of retinal layers in optical coherence tomography images using a machine learning algorithm

Quantifying the smoothness of different layers of the retina can potentially be an important and practical biomarker in various pathologic conditions like diabetic retinopathy. The purpose of this study is to develop an automated machine learning algorithm which uses support vector regression method with wavelet kernel and automatically segments two hyperreflective retinal layers (inner plexiform layer (IPL) and outer plexiform layer (OPL)) in 50 optical coherence tomography (OCT) slabs and calculates the smoothness index (SI). The Bland-Altman plots, mean absolute error, root mean square error and signed error calculations revealed a modest discrepancy between the manual approach, used as the ground truth, and the corresponding automated segmentation of IPL/ OPL, as well as SI measurements in OCT slabs. It was concluded that the constructed algorithm may be employed as a reliable, rapid and convenient approach for segmenting IPL/OPL and calculating SI in the appropriate layers.

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.

Geometric Morphometrics Can Predict Postoperative Visual Acuity Changes in Patients With Epiretinal Membrane: A Retrospective Study

Purpose

To investigate the efficacy of the geometric morphometrics method for the evaluation of retinal deformation in patients with epiretinal membrane (ERM) and determine whether the degree of deformation can serve as a predictive factor for postoperative visual outcome.

Methods

We retrospectively evaluated data from 29 eyes of 29 patients with primary ERM. Preoperative optical coherence tomography images were compared with images of their normal fellow eyes using the geometric morphometrics thin-plate spline technique. Conventional parameters such as retinal layer thickness and previously reported indices were also measured. The correlation between the preoperative parameters and visual acuity was evaluated. Statistical comparisons were performed using a paired t-test, and associations between the optical coherence tomography image parameters and visual acuity were determined using Spearman's rank correlation coefficient.

Results

Bending energy, which was calculated using geometric morphometrics, was significantly associated with visual acuity as well as conventional optical coherence tomography parameters and previously reported indices. Multiple regression analysis showed that bending energy was an independent predictive factor for postoperative visual acuity changes.

Conclusions

The geometric morphometrics method is an effective approach for evaluating the severity of ERM and predicting the efficacy of surgery.

Translational Relevance

Geometric morphometrics can effectively evaluate retinal deformation in eyes with epiretinal membrane.

Evaluation of the optical coherence tomography findings of patients with idiopathic epiretinal membrane

BACKGROUND

This study aimed to determine the relationship between basal visual acuity (VA) and basal optical coherence tomography (OCT) parameters of patients with idiopathic epiretinal membrane (iERM).

METHODS

The study included 200 eyes of 200 patients with iERM. In the evaluation of basal VAs, logMAR 0.3 (0.5 on Snellen chart) was accepted as the limit, and the patients were divided into two groups as Group 1 with VA values below logMAR 0.3 and Group 2 with those above logMAR 0.3. Using OCT, the ellipsoid zone (EZ), interdigitation zone (IZ), external limiting membrane (ELM) integrity, peaked appearance of EZ in the fovea, disorganization of the inner retinal layers (DRIL), central foveal thickness (CFT), maximum retinal thickness (MRT), total photoreceptor length (TPL), photoreceptor outer segment length (PROSL), photoreceptor deformity index (PDI), and inner retinal layer irregularity index (IRLII) were evaluated and compared between the groups.

RESULTS

There were an equal number of patients in Group 1 and Group 2. The preservation of ELM, EZ, and IZ integrity and the peaked appearance of EZ in the fovea were observed at higher rates in Group 1, whereas the rate of DRIL was higher in Group 2 (p < 0.05 for all). In the multiple regression analysis performed to evaluate categorical OCT parameters, only the presence of DRIL was found to be significantly associated with VA (p < 0.003). CFT*, MRT*, and IRLII** were significantly lower in Group 1 (*p < 0.001, **p = 0.001). TPU, PROSL, and FDI were similar between the two groups (p > 0.05 for all).

CONCLUSION

According to the multiple regression analysis, only the presence of DRIL was correlated with lower VA values. Among the OCT parameters, an increase in CFT and MRT, as well as the IRLII value moving away from 1 were related to lower VA values.

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.

Prediction of Visual Impairment in Epiretinal Membrane and Feature Analysis: A Deep Learning Approach Using Optical Coherence Tomography

PURPOSE

The aim was to develop a deep learning model for predicting the extent of visual impairment in epiretinal membrane (ERM) using optical coherence tomography (OCT) images, and to analyze the associated features.

METHODS

Six hundred macular OCT images from eyes with ERM and no visually significant media opacity or other retinal diseases were obtained. Those with best-corrected visual acuity ≤20/50 were classified as "profound visual impairment," while those with best-corrected visual acuity >20/50 were classified as "less visual impairment." Ninety percent of images were used as the training data set and 10% were used for testing. Two convolutional neural network models (ResNet-50 and ResNet-18) were adopted for training. The t-distributed stochastic neighbor-embedding approach was used to compare their performances. The Grad-CAM technique was used in the heat map generative phase for feature analysis.

RESULTS

During the model development, the training accuracy was 100% in both convolutional neural network models, while the testing accuracy was 70% and 80% for ResNet-18 and ResNet-50, respectively. The t-distributed stochastic neighbor-embedding approach found that the deeper structure (ResNet-50) had better discrimination on OCT characteristics for visual impairment than the shallower structure (ResNet-18). The heat maps indicated that the key features for visual impairment were located mostly in the inner retinal layers of the fovea and parafoveal regions.

CONCLUSIONS

Deep learning algorithms could assess the extent of visual impairment from OCT images in patients with ERM. Changes in inner retinal layers were found to have a greater impact on visual acuity than the outer retinal changes.

Insights into the underlying choroid in different stages of idiopathic epiretinal membranes after Viteromacular surgery

PURPOSE

The purpose of the study was to longitudinally investigate the correlation between choroidal morphologic and vascular parameters and postoperative visual outcome in different stages of idiopathic epiretinal membranes (iERMs).

METHODS

A prospective, observational, institutional case series of 102 consecutive patients diagnosed with unilateral iERMs were recruited at Peking University Third Hospital and were followed up for 12 months after surgical treatment with vitrectomy. Participants were classified into four stages according to current staging scheme. All eligible subjects underwent standardized imaging evaluation of choroidal parameters including subfoveal choroidal thickness (SFCT), choroidal vascularity index (CVI), and choroidal capillary perfusion (CCP) at baseline and each follow-up by enhanced depth optical coherence tomography (EDI-OCT) and OCT angiography (OCTA). Longitudinal follow-up of choroidal parameters over 12 months was analysed, and their correlations with best-corrected visual acuity (BCVA) were also assessed for predictive prognostic value.

RESULTS

CVI and CCP were significantly correlated with BCVA at each follow-up examination (all p < 0.05). However, SFCT exhibited no variation among different stages of iERMs at baseline (p = 0.981) or during follow-up (p = 0.520). The preoperative CVI correlated with 12-month postoperative BCVA (p < 0.001) and its predictive prognostic effect on BCVA was validated in multiple regression analysis (p = 0.006).

CONCLUSION

CVI varied among different stages of iERM and was significantly correlated with visual outcomes after the surgery. CVI could serve as a predictive prognostic marker in iERMs, which further indicates the underlying choroid should be taken into consideration in clinical evaluation of iERMs.

Changes in foveal photoreceptor integrity after idiopathic epiretinal membrane surgery and its relationship with visual outcomes

PURPOSE

To investigate the changes in the external limiting membrane (ELM), ellipsoid zone (EZ), and interdigitation zone (IZ) integrity and their relationship with visual outcomes after idiopathic epiretinal membranes peeling.

METHODS

Clinical records of 150 eyes from 144 consecutive patients who underwent vitrectomy were reviewed. The status of IZ, EZ, and ELM was assessed by spectral-domain optical coherence tomography at baseline and 1, 4, 10, and 24 months postoperatively.

RESULTS

Sixty-one eyes presented with photoreceptor layer disruption preoperatively, and IZ disruption (40.7%) was the primary type. The best-corrected visual acuity (BCVA) in the photoreceptor disruption group was significantly lower than that in the intact group at baseline and the final follow-up. Of them, ELM + EZ + IZ disruption showed the worst BCVA (P = 0.001). After surgery, 62 eyes were observed with disruption aggravated. EZ + IZ disruption (51.0%) was the most frequent type at 1 month postoperatively. The eyes with longer symptom duration, better BCVA, earlier stage, thinner CFT at baseline, and combined cataract surgery more tended to be observed with photoreceptor damage progressed after surgery (P < 0.05). There was no significant difference in the final BCVA between the eyes with and without damage progressed (P = 0.332). Finally, 28.1% of the eyes recovered photoreceptor continuity. The eyes with foveal photoreceptor integrity restored had better BCVA than those remaining discontinuous (P < 0.001).

CONCLUSION

ERM-induced photoreceptor disruption mainly manifests as IZ disruption and has a negative effect on BCVA, whereas surgery mainly causes EZ and IZ disruption, which does not have a significant impact on the final BCVA.

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.

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.

Incidence and risk factors of progressive nasal inner nuclear layer thickening after surgical peeling of epiretinal membrane

To assess incidence and risk factors of postoperative progressive nasal inner nuclear layer (INL) thickening after epiretinal membrane (ERM) surgery. Progressive nasal INL thickening was defined as 1.5-fold increase in thickness of nasal INL after ERM surgery compared to preoperative examination. Kaplan–Meier survival analysis was done to compare the cumulative risk ratio between groups stratified by presence of progressive nasal INL thickening. Logistic regression was performed to identify possible risk factors. Progressive nasal INL thickening occurred in 13.0% of ERM removal patients. Patients without progressive nasal INL thickening showed better visual acuity recovery compared to patients with nasal INL thickening (p = 0.029). Presence of cystoid space in inner retinal layer before surgery (odds ratio [OR] = 0.143, 95% confidence interval [CI] 0.028–0.736; p = 0.020), older age (OR = 0.896, 95% CI 0.817–0.982, p = 0.020), and thicker preoperative central macular thickness (OR = 0.994, 95% CI 0.988–1.000, p = 0.039) were correlated inversely with thickening of nasal INL. Correlation between nasal INL thickness and postoperative visual outcome was significant. Absence of cystoid space before ERM surgery, younger age, and thinner central macular thickness were risk factors for progressive postoperative nasal INL thickening. Progressive nasal INL thickening may serve as a new biomarker for worsened visual symptom after ERM surgery.

Idiopathic Epiretinal Membranes: Visual Outcomes and Prognostic Factors

Objectives

To evaluate the associations between anatomical changes and visual outcomes in patients with idiopathic epiretinal membrane (ERM).

Materials and Methods

We performed a prospective study of 130 consecutive idiopathic ERM patients and report their visual outcomes and the factors associated with visual outcome and anatomical changes.

Results

Of 130 eyes of 130 patients, 87 eyes underwent surgery, while the remaining 43 eyes were observed. At 6-month follow-up, the best-corrected visual acuity (BCVA) increased in the whole population. Mean Early Treatment Diabetic Retinopathy Study letter score changed from 51 to 65 in the surgical group and from 67 to 68 in the non-surgical group. The surgical group had improvement in BCVA at all ERM stages and grades of disorganization of the retinal inner layers (DRIL) (p<0.01). In multivariable analysis of the surgical group, factors associated with BCVA of ETDRS 60 letters or more were no or mild DRIL and the absence of ellipsoid zone disruption at baseline (p=0.002 and p=0.034, respectively) and this statistically significant positive correlation was still maintained at 12-month follow-up.

Conclusion

Baseline DRIL grade and presence of ellipsoid zone disruption were the most informative prognostic factors in patients with idiopathic ERMs. Patients with severe DRIL and/or advanced ERMs had improved vision after ERM removal.

Effects of Ectopic Inner Foveal Layers on Foveal Configuration and Visual Function after idiopathic Epiretinal Membrane Surgery

PURPOSE

To investigate the effects of ectopic inner foveal layers (EIFLs) on foveal configuration recovery and visual acuity (VA) after idiopathic epiretinal membrane (iERM) removal and analyze the relationship of foveal configuration recovery between 1-month and long-term postoperatively.

METHODS

This retrospective study included 216 consecutive eyes with iERM that underwent vitrectomy surgery. A comprehensive ophthalmic examination was performed for all patients before and 1, 4,10, and 24 months after surgery. We observed the postoperative anatomical and functional recovery of eyes with and without EIFLs and analyzed the association between short-term and long-term anatomical recovery.

RESULTS

The presence of EIFL was associated with severe preoperative visual damage (P＜0.001) and was considered as a negative factor for postoperative foveal depression recovery (P＜0.001). No significant difference was found in postoperative BCVA between the eyes with and without EIFLs (P=0.442). For eyes with stage II ERMs, 17.6% developed EIFLs postoperatively, which did not affect the final BCVA. Overall, 24.5% of ERMs restored the foveal configurations at 1 month postoperatively, and 14.7% continued recovering during the follow-up. Foveal structure recovery in eyes with EIFLs was associated with earlier stage, fewer microcystic macular edema, complete IZ layer, and a thinner CFT (All P＜0.05) at 1-month postoperatively.

CONCLUSIONS

The EIFL is associated with severe preoperative visual damage and is a negative factor for postoperative anatomical recovery, but it is a minor factor for postoperative VA. We also found an association of foveal configuration recovery between 1-month and long-term after surgery.

Idiopathic epiretinal membrane: progression and timing of surgery

Primary idiopathic epiretinal membrane (iERM) is a common finding, particularly so in the era of high street spectral-domain optical coherence tomography. Clinicians often face the dilemma of early versus delayed surgical intervention in the management of iERM with macular pucker, especially in those patients with good vision. The aim of this review is to assist clinicians in their understanding of the natural history of iERM to enable decision-making and optimally advising patients. We systematically searched the Medline and EMBASE databases for relevant publications from 2001 onwards using defined search terms with pre-planned inclusion and exclusion criteria. In this article, we review the epidemiology of iERM, classifications, their effect on visual function, the natural history and factors predicting progression and finally, factors which might predict the visual outcome with surgery.

Predictive value of ectopic inner foveal layer without internal limiting membrane peeling for idiopathic epiretinal membrane surgery

PURPOSE

To investigate the clinical importance of ectopic inner foveal layer (EIFL) grading (mild to severe) in patients diagnosed with idiopathic epiretinal membrane (iERM) and had pars plana vitrectomy (PPV) with solely ERM peeling.

MATERIALS AND METHODS

Patients diagnosed with iERMs who had undergone PPV including only ERM peeling were enrolled in the study, and follow-up findings were recorded at baseline, and at 3, 6, 12 months and final examinations. EIFL was categorized into four grades, from mild to severe. Pre- and postoperative anatomical changes were measured using spectral domain optical coherence tomography (SD-OCT) imaging. The association between EIFL and other SD-OCT parameters with best-corrected visual acuity (BCVA) was assessed before and after PPV surgery.

RESULTS

One-hundred thirty-eight eyes of 106 patients with mild to severe EIFL were included in the study. Higher EIFL thickness was significantly correlated with lower baseline (r = 0.575, p = 0.020) and final BCVA (r = 0.748, p = 0.001). Although EIFLs continued in advanced-stage cases (stage 3 and 4) (64 eyes [82%]) at the final visit, it was observed in 8 eyes (23%) in the early stage (stage 2) of iERMs. A strong positive correlation was found between EIFL thickness and recurrence rate of ERM (r = 0.876, p < 0.001). Recurrence of ERM was detected in 27 eyes; 2 (7%) at stage 1, 3 (9%) at stage 2, 10 (23%) in stage 3, and 12 (33%) in stage 4 (p < 0.001).

CONCLUSION

A negative association was found between the severity of EIFL and postoperative anatomical and visual recovery. In terms of surgical timing, early stages (stages 1 and 2) may be preferred for providing good anatomical and visual recovery and a low recurrence rate following surgery.

Macular pigment optical density assessed by heterochromatic flicker photometry in eyes affected by primary epiretinal membrane

PURPOSE

To compare macular pigment optical density (MPOD) in healthy eyes vs eyes affected by primary epiretinal membrane (ERM) in different stages and to assess the relation between MPOD and optical coherence tomography findings.

METHODS

Prospective cross-sectional study of 62 eyes from 62 patients affected by unilateral primary ERM. Contralateral healthy eyes from the same patients were used as a control group. Main outcome measures were MPOD, ERM stage, central foveal thickness (CFT), outer nuclear layer thickness (ONLT), integrity of outer retinal bands (ORB) and presence of Central Bouquet (CB) abnormalities.

RESULTS

In the study group mean CFT was 444±75 µm and mean ONLT was 245±40 µm, while in the control group mean CFT was 230±21 µm and mean ONLT was 102±14 µm (p<0.001). Mean MPOD was 0.86±0.07 in eyes with ERM and 0.48±0.09 in contralateral healthy eyes (p<0.001). MPOD was associated with CFT (p=0.006) and ONLT (p<0.001) while no significant associations were observed between MPOD and ORB integrity (p=0.14) and CB abnormalities (p=0.08).

CONCLUSIONS

MPOD increased in eyes affected by primary ERM proportionally to CFT and, especially, ONLT. Probably, centripetal forces exerted by ERM contraction on the retinal surface lead to a progressive foveal packing of foveal Muller cells.

Effect of Foveal Pit Restoration in Foveal Avascular Zone After Surgery for idiopathic Epiretinal Membrane

Purpose

To investigate the relationship between ophthalmic parameters—including optical coherence tomography (OCT) and OCT angiography findings—and foveal pit restoration in eyes that had undergone vitrectomy for idiopathic epiretinal membrane (iERM) removal.

Methods

This study retrospectively analyzed data of patients who underwent pars planar vitrectomy for the removal of epirentinal membrane. Only eyes with iERM above stage 2 with a follow-up over 6 months were included. Baseline data and changes in ophthalmic parameters were analyzed from 3 months before to 12 months after surgery. Additionally, we stratified iERM patients into two groups (foveal pit restoration and no restoration group). Longitudinal comparison analyses between the two groups were done in best-corrected visual acuity (BCVA), central foveal thickness (CFT) and foveal avascular zone (FAZ) areas measurements using swept-source OCT and OCT angiography.

Results

Forty-three patients with a mean age of 75 ± 5 years were enrolled. After surgery, BCVA, FAZ, and CFT showed improvements over time (all p < 0.002). Thirty-one patients were designated into the foveal pit restoration (R) group and 12 patients into the no restoration (NR) group. Differences in BCVA and FAZ area in both groups existed up to 6 months. However, BCVA improved and FAZ expanded (R, 0.20 ± 0.05 vs. NR, 0.18 ± 0.04) in both groups showing no statistical difference 12 months postsurgery. The CFT decreased in both groups, but the R group was thinner at every point compared to the NR group (all p < 0.05).

Conclusions

The removal of epirentinal membrane in pars planar vitrectomy significantly improves BCVA, decreases the CFT and expands the FAZ. Foveal pit restoration improves BCVA, CFT, and FAZ area possibly at a faster rate in the early months but long-term improvements could be achieved regardless of the status of foveal pit restoration.

Influence of postoperative ectopic inner foveal layer on visual function after removal of idiopathic epiretinal membrane

Purpose

To investigate the functional and anatomical parameters and their postoperative changes according to the ectopic inner foveal layer (EIFL) staging scheme for idiopathic epiretinal membrane (ERM).

Methods

In this prospective study, patients with idiopathic ERM underwent pars plana vitrectomy and ERM removal, and were followed-up for 6 months. The associations of EIFL with pre- and postoperative functional and anatomical parameters were analyzed.

Results

A total of 84 eyes (84 patients) were included: 39 (46.4%), 33 (39.3%), and 12 (14.3%) as EIFL stages 2, 3, and 4, respectively. At 6 months after surgery, the mean best-corrected visual acuity (BCVA) significantly improved in all EIFL stages (P ≤ 0.003); however, metamorphopsia improved only in eyes with EIFL stage 2 (P = 0.039) and 3 (P = 0.011). The aniseikonia and foveal avascular zone (FAZ) area showed no significant postoperative changes in any of the EIFL stages. Both preoperatively and during 6 months after surgery, the EIFL stage showed a significant correlation with BCVA (P ≤ 0.033), metamorphopsia (P ≤ 0.008), central macular thickness (P < 0.001), and FAZ parameters (P ≤ 0.016) at each time point, but not with aniseikonia. Significant correlations of EIFL thickness with BCVA (P = 0.028) and metamorphopsia (P = 0.006) before surgery were not persistent after surgery.

Conclusion

Both pre- and postoperatively, the staging of EIFL, rather than its thickness, is a simple and adequate surrogate marker for visual acuity and metamorphopsia in eyes with idiopathic ERM.

FOVEAL DISPLACEMENT IN EYES WITH EPIRETINAL MEMBRANE AFTER VITRECTOMY AND MEMBRANE PEELING

PURPOSE

To investigate the foveal movement in eyes with epiretinal membrane after vitrectomy and membrane peeling.

METHODS

A retrospective review of 85 eyes with epiretinal membrane treated with vitrectomy, membrane peeling, and internal limiting membrane removal. Using a self-designed computer program to compare the preoperative and postoperative images of optical coherence tomography to measure the amount of foveal movement. Analyze the relationships between foveal displacement, preoperative and postoperative best-corrected visual acuity, central foveal thickness, and the stage of epiretinal membrane.

RESULTS

Most of the fovea were nasally shifted. More movement happened in the first month and almost finished in the first year. The greater degree of foveal displacement was correlated with poorer initial visual acuity and thicker central foveal thickness. In considering with the ectopic inner foveal layer staging of epiretinal membrane by structural optical coherence tomography, the foveal realignment is greatest in Stage 4 (394.47 ± 171.44 µm), followed by Stage 1 (251.21 ± 135.40 µm), Stage 2 (235.70 ± 147.51 µm), and Stage 3 (219.86 ± 117.91 µm) at the postoperative 1 month.

CONCLUSION

Most eyes of epiretinal membrane had the foveal moved nasally after membrane peeling and internal limiting membrane peeling. The larger amount of foveal movement was correlated with poorer initial best-corrected visual acuity. Dystopia fovea may be another factor affecting visual acuity in addition to other biomarkers in optical coherence tomography.

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.

TEMPORAL CHANGES OF PARAFOVEAL MICROVASCULATURE AFTER EPIRETINAL MEMBRANE SURGERY: An Optical Coherence Tomography Angiography Study

PURPOSE

To investigate whether the parafoveal capillary architecture predicts clinical course and visual outcomes after epiretinal membrane (ERM) surgery.

METHODS

A total of 71 eyes of 71 patients treated with vitrectomy for idiopathic ERM were enrolled. The parafoveal capillary displacement and fractal geometries were compared according to the stage of ERM. Correlations between the parafoveal capillary displacement in the superficial capillary plexus, the fractal dimension and lacunarity in the deep capillary plexus (DCP), foveal thickness, and visual outcomes were evaluated.

RESULTS

Compared with eyes with mild ERM, eyes with severe ERM exhibited higher parafoveal capillary displacement in the superficial capillary plexus, lower fractal dimension and higher lacunarity in the DCP, and greater foveal thickness (P < 0.05). The parafoveal capillary displacement in the superficial capillary plexus and fractal dimension and lacunarity in the DCP improved significantly, particularly at 1 month postoperatively (P < 0.05) and reached a plateau thereafter. The preoperative fractal dimension in the DCP showed a significant correlation with the best-corrected visual acuity at all follow-up time points (P < 0.05).

CONCLUSION

The parafoveal fractal dimension in the DCP was significantly correlated with the visual acuity before and after ERM surgery. The parafoveal fractal dimension may serve as a predictive marker for visual outcomes after ERM surgery.

Livelayer: a semi-automatic software program for segmentation of layers and diabetic macular edema in optical coherence tomography images

Given the capacity of Optical Coherence Tomography (OCT) imaging to display structural changes in a wide variety of eye diseases and neurological disorders, the need for OCT image segmentation and the corresponding data interpretation is latterly felt more than ever before. In this paper, we wish to address this need by designing a semi-automatic software program for applying reliable segmentation of 8 different macular layers as well as outlining retinal pathologies such as diabetic macular edema. The software accommodates a novel graph-based semi-automatic method, called "Livelayer" which is designed for straightforward segmentation of retinal layers and fluids. This method is chiefly based on Dijkstra's Shortest Path First (SPF) algorithm and the Live-wire function together with some preprocessing operations on the to-be-segmented images. The software is indeed suitable for obtaining detailed segmentation of layers, exact localization of clear or unclear fluid objects and the ground truth, demanding far less endeavor in comparison to a common manual segmentation method. It is also valuable as a tool for calculating the irregularity index in deformed OCT images. The amount of time (seconds) that Livelayer required for segmentation of Inner Limiting Membrane, Inner Plexiform Layer-Inner Nuclear Layer, Outer Plexiform Layer-Outer Nuclear Layer was much less than that for the manual segmentation, 5 s for the ILM (minimum) and 15.57 s for the OPL-ONL (maximum). The unsigned errors (pixels) between the semi-automatically labeled and gold standard data was on average 2.7, 1.9, 2.1 for ILM, IPL-INL, OPL-ONL, respectively. The Bland-Altman plots indicated perfect concordance between the Livelayer and the manual algorithm and that they could be used interchangeably. The repeatability error was around one pixel for the OPL-ONL and < 1 for the other two. The unsigned errors between the Livelayer and the manual algorithm was 1.33 for ILM and 1.53 for Nerve Fiber Layer-Ganglion Cell Layer in peripapillary B-Scans. The Dice scores for comparing the two algorithms and for obtaining the repeatability on segmentation of fluid objects were at acceptable levels.

Evaluation of postoperative visual function based on the preoperative inner layer structure in the epiretinal membrane

PURPOSE

To evaluate the postoperative visual function using a preoperative epiretinal membrane (ERM) classification based on the status of the inner layer structure.

METHODS

We assessed 62 eyes, one from each patient undergoing vitrectomy with internal limiting membrane (ILM) peeling for unilateral ERM. The inclusion criteria were as follows: (1) the presence of idiopathic ERM based on optical coherence tomography and a healthy contralateral eye, (2) successful surgery after 25- or 27-gauge transconjunctival 3-port pars plana vitrectomy with ILM peeling, and (3) a minimum follow-up period of 12 months. We included patients with preoperative ERM morphology with no disruption of the inner retinal layer in group A (37 eyes) and those with disruption in group B (25 eyes) and compared the visual acuity, central visual-field sensitivity (CVFS) measured using the Humphrey field analyzer 10-2 program, and detection rate of micro-scotoma (< 10 dB) at baseline and 12 months postoperatively between the groups.

RESULTS

Visual acuity at 12 months showed greater improvement in group A than in group B (P = .03). There was no significant difference in CVFS at baseline; however, that of the nasal area was substantially lower after surgery in group B than in group A (P = .02). The 12-month postoperative detection rate of micro-scotoma was significantly higher in group B than in group A (P = .002).

CONCLUSION

ERM that has preoperatively disrupted the inner layer poses the risks of CVFS reduction and micro-scotoma formation after vitrectomy. Evaluating the inner layer could be an important prognostic factor in determining retinal function in ERM.

CORRELATION BETWEEN MACULAR MICROSTRUCTURES AND ANISEIKONIA AFTER IDIOPATHIC EPIRETINAL MEMBRANE REMOVAL

PURPOSE

To analyze the correlation between preoperative measurements of macular microstructures and aniseikonia after epiretinal membrane removal.

METHODS

This retrospective study included 32 eyes of 32 patients who underwent epiretinal membrane surgery and were followed up for 12 months. Spectral-domain optical coherence tomography was used to measure the thicknesses of the ganglion cell layer-inner plexiform layer, inner nuclear layer (INL), and outer retinal layer in macular microstructures. The new aniseikonia test was used to measure vertical and horizontal aniseikonia scores.

RESULTS

There was a significant decrease in central macular thickness and ganglion cell layer-inner plexiform layer thickness at 6 and 12 months postoperatively (all P < 0.001). Vertical aniseikonia scores, horizontal aniseikonia scores, and INL and outer retinal layer thicknesses did not show significant changes. Vertical aniseikonia scores and horizontal aniseikonia scores were significantly associated with INL thicknesses of each meridian at each follow-up time point (all P < 0.05). Preoperative vertical and horizontal INL thicknesses were correlated with vertical aniseikonia scores and horizontal aniseikonia scores at 12 months postoperatively (P = 0.014 and P = 0.002, respectively).

CONCLUSION

Aniseikonia values did not change after epiretinal membrane removal and were associated with INL thickness before and after surgery. Thus, preoperative INL thickness could be used as a predictor of surgical prognosis in epiretinal membrane patients.

Epiretinal membrane: A review

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

Prediction of Visual Prognosis after Epiretinal Membrane Surgery Using Regression Tree Analysis

Background and Objective: Confounding factors should be considered when predicting visual prognosis after epiretinal membrane (ERM) surgery. We aimed to predict visual acuity after ERM surgery using regression tree analysis.Patients and Methods: We retrospectively reviewed 343 eyes of 343 patients who underwent vitrectomy for idiopathic ERM. Regression tree analysis was performed to predict best-corrected visual acuity (BCVA) at 6 months postoperatively.Results: Patients were first divided into two groups based on preoperative BCVA. Age, central macular thickness, and axial length were associated with visual prognosis in patients with specific preoperative BCVAs. When patients were subdivided into groups 1-8, BCVA was significantly better in group 1 than in groups 4-8 (p≤0.001), and in groups 2-5 and 7 than in groups 6 and 8 (p≤0.002).Conclusion: Surgical prognosis in eyes with ERM should be evaluated based on a comprehensive assessment of preoperative characteristics.

Usefulness of the Components of Full-Field Electroretinography to Predict Postoperative Visual Outcomes in Patients With Epiretinal Membranes

Purpose

To confirm the predictors of postoperative visual outcomes by performing full-field electroretinography (ffERG) before surgery in patients with epiretinal membranes (ERMs).

Methods

Sixty-one eyes of patients with ERMs who underwent pars plana vitrectomy with membrane peeling were prospectively reviewed. Correlations between preoperative data (ffERG and optical coherence tomography) and postoperative best-corrected visual acuity (BCVA) were investigated. Receiver operating characteristic (ROC) curve analysis was performed to obtain cutoff values of the ffERG parameters predicting good visual outcome (final BCVA ≥ 20/30).

Results

Postoperative BCVA was significantly correlated with the implicit time and amplitude of the b-wave in light-adapted (LA) 3.0 electroretinography (ERG), with the amplitude difference between N1 and P1 in the LA 30-Hz flicker ERG, and with the sum of the amplitudes of OS1, OS2, and OS3 in dark-adapted (DA) oscillatory potential (OP) ERG (P < 0.01). The area under the ROC curve to predict good visual outcome was statistically significant for the four parameters (0.787, 0.815, 0.757, and 0.792, respectively).

Conclusions

The postoperative BCVA in patients with ERM was significantly correlated with the implicit time and amplitude of the b-wave in the LA 3.0 ERG, the amplitude difference between N1 and P1 in the LA 30-Hz flicker ERG, and the sum of the amplitudes of OS1, OS2, and OS3 in DA OP ERG of ffERG. It is thought that ffERG before surgery may help predict visual outcomes after surgery.

Translational Relevance

It was confirmed that the degree of retinal function in the ERM can predict BCVA after treatment.

Novel Optical Coherence Tomography Parameters as Prognostic Factors for Stage 3 Epiretinal Membranes

Purpose

We aimed to describe the visual prognosis of eyes with ectopic inner foveal layers (EIFLs) after epiretinal membrane (ERM) surgery.

Methods

This retrospective study enrolled patients diagnosed with stage 3 ERM based on the EIFL staging scheme who underwent ERM surgery with a minimum follow-up period of 12 months. Central foveal thickness (CFT), EIFL thickness, and the length of the ellipsoid zone defect were evaluated at baseline and at 1 month, 6 months, and 12 months after surgery based on pre- and postoperative swept-source optical coherence tomography (OCT) images. The association of EIFL thickness and other OCT parameters with pre- and postoperative best-corrected visual acuity (BCVA) was analyzed.

Results

Sixty-nine eyes with stage 3 ERMs were analyzed. Preoperative BCVA was correlated with preoperative CFT (r = 0.517, p < 0.001) and preoperative EIFL thickness (r = 0.652, p < 0.001). At 12 months, postoperative BCVA was correlated negatively with preoperative CFT (r = 0.470, p=0.016) and preoperative EIFL thickness (r = 0.582, p=0.004). The improvement in BCVA was not associated with postoperative reduction in CFT (p=0.06), although it was significantly associated with postoperative reduction in EIFL thickness (r = 0.635, p=0.007).

Conclusions

EIFL thickness should be considered a negative prognostic factor for postoperative anatomical and functional recovery in patients with stage 3 ERMs.

Optical coherence tomography biomarkers for visual acuity in patients with idiopathic epiretinal membrane

PURPOSE

To investigate the correlation between outer and inner retina optical coherence tomography (OCT) biomarkers and visual acuity in patients with idiopathic epiretinal membrane (iERM) and identify which of them may be predictive of visual function.

METHODS

A retrospective cross-sectional single-center study was conducted that included patients diagnosed with iERM. Spectral domain OCT images were obtained and assessed qualitatively and quantitatively. The association of OCT parameters with best corrected visual acuity was analyzed.

RESULTS

Charts of 97 eyes of 97 patients were reviewed. Central foveal thickness, maximal retinal thickness (MRT), photoreceptor outer segment length, outer foveal thickness, ganglion cell-inner plexiform layer complex thickening, inner retinal thickness and inner retinal layer irregularity index were among the major outcome measures. OCT scans were also assessed for the presence of cotton ball sign, ellipsoid zone disruption, ectopic inner foveal layer, disorganization of retinal inner layers (DRIL), intraretinal fluid, subretinal fluid (SRF) and epimacular membrane rip. Univariate analysis showed statistically significant association between all the aforementioned parameters with worse vision, except for cotton ball sign and SRF. Multivariate analysis found that MRT and severe DRIL were strongly correlated with worse vision (p < 0.001).

CONCLUSION

MRT and severe DRIL should be considered as negative prognostic factors for visual acuity.

Evaluation of retinal vascular structure after epiretinal membrane surgery by optical coherence tomography angiography

PURPOSE

To evaluate the retinal vascular structure before and after the epiretinal membrane (ERM) surgery by optical coherence tomography angiography (OCTA).

METHODS

Twenty-two eyes with ERM (study eyes) had been evaluated by OCTA for superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel density (VD) at foveal and parafoveal regions and foveal avascular zone (FAZ) before and after ERM removal surgery. Twenty-two fellow eyes were selected as control group.

RESULTS

Preoperative VD of SCP and DCP were significantly lower in ERM eyes than in controls in both foveal and parafoveal areas (p < 0.05, for all). The difference regressed in SCP (fovea: 18.04 ± 3.1 vs 19.98 ± 18 p = 0.002 and parafovea: 47.33 ± 3.54 vs 49.71 ± 28 p = 0.001), but persisted in DCP (fovea: 17.25 ± 3.52 vs 17.57 ± 4.01 p = 0.856 and parafovea: 50.12 ± 4.35 vs 50.93 ± 3.24 p = 0.791) in study eyes, postoperatively. Superficial and deep FAZ areas were significantly smaller in study eyes than controls. Postoperatively, superficial FAZ area enlarged (0.288 ± 0.10 vs 0.307 ± 0.08 p = 0.012), whereas deep FAZ area did not (0.324 ± 0.09 vs 0.338 ± 0.07 p = 0.435). FAZ area was correlated with the best-corrected visual acuity in ERM eyes.

CONCLUSION

Vascular damage in SCP and DCP was demonstrated by OCTA in eyes with ERM. ERM removal surgery mainly improves superficial changes caused by ERM. Changes in deep retinal flow may be associated with visual outcomes after ERM removal surgery.

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.

Baseline visual acuity and interdigitation zone as predictors in idiopathic epiretinal membranes: A retrospective cohort study

OBJECTIVE

Determine which functional and anatomical characteristics may be predictors of final visual acuity in patients with idiopathic ERM (iERM) submitted to pars plana vitrectomy (PPV) with ERM and internal and internal limiting membrane (ILM) peeling.

DESIGN

Retrospective cohort study.

SUBJECTS

Patients with iERM submitted to PPV between 2016 and 2017.

METHODS

Data regarding the best-corrected visual acuity (BCVA) and the characteristics of the retinal layers observed in SD-OCT were collected preoperatively and until 12 months postoperatively. Central macular thickness (CMT), disorganization of the retinal inner layers (DRIL), outer nuclear layer (ONL) thickness, integrity of subfoveal external limiting membrane (ELM), ellipsoid zone (EZ), and interdigitation zone (IZ) were evaluated.

RESULTS

A total of 128 eyes with iERM from 121 patients were included. BCVA improved significantly (p < 0.001). Significant improvement of BCVA, CMT, DRIL, ONL, ELM, and EZ were obtained. The final IZ was not different from baseline until the end of the study. A significant correlation was observed between the baseline BCVA, EZ, IZ, and the postoperative BCVA (p < 0.001). However, only the baseline BCVA and the integrity of the subfoveal baseline IZ were predictive factors for final BCVA (p < 0.005 and p < 0.001, respectively).

CONCLUSION

PPV provides a significant improvement of BCVA and retinal anatomy recovery in iERM eyes. Baseline IZ didn't change during the 12 months following surgery. Baseline BCVA and subfoveal IZ at baseline were prognostic factors for the final BCVA.