CORRELATION BETWEEN INNER-RETINAL CHANGES AND OUTER-RETINAL DAMAGE IN PATIENTS WITH IDIOPATHIC EPIRETINAL MEMBRANE

RHOMBUS DEFORMATION OF RETINAL LATERAL DISPLACEMENT AFTER EPIRETINAL MEMBRANE REMOVAL REVEALED BY DIFFEOMORPHIC IMAGE REGISTRATION

PURPOSE

To establish an analysis method using diffeomorphic image registration and evaluate microvascular displacement through epiretinal membrane (ERM) removal.

METHODS

Medical records of eyes that underwent vitreous surgery for ERM were reviewed. Postoperative optical coherence tomography angiography (OCTA) images were converted to the corresponding preoperative images according to a configured algorithm using diffeomorphism.

RESULTS

Thirty-seven eyes with ERM were examined. Measured changes in the foveal avascular zone (FAZ) area showed a significant negative correlation with central foveal thickness (CFT). The average amplitude of microvascular displacement calculated for each pixel was 69 ± 27 µ m in the nasal area, which was relatively smaller than that in other areas. The vector map, which included both the amplitude and the vector of microvasculature displacement, showed a unique vector flow pattern called the rhombus deformation sign in 17 eyes. Eyes with this deformation sign showed less surgery-induced changes in the FAZ area and CFT and a milder ERM stage than those without this sign.

CONCLUSION

The authors calculated and visualized microvascular displacement using diffeomorphism. The authors found a unique pattern (rhombus deformation) of retinal lateral displacement through ERM removal, which was significantly associated with the severity of ERM.

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.

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.

PREVALENCE AND RISK FACTORS OF ELLIPSOID ZONE DAMAGE AFTER PARS PLANA VITRECTOMY FOR IDIOPATHIC EPIRETINAL MEMBRANE

PURPOSE

To assess factors associated with external limiting membrane (ELM)/ellipsoid zone (EZ) damage after pars plana vitrectomy (PPV) for epiretinal membrane and evaluate ELM/EZ damage impact on functional and anatomical outcomes.

METHODS

Patients who underwent PPV with epiretinal membrane ± inner limiting membrane peeling were retrospectively analyzed. Best-corrected visual acuity and central macular thickness were longitudinally collected based on the available follow-up. Demographic data, clinical data, and surgical details were included in logistic regression models having ELM/EZ damage as a binary outcome.

RESULTS

Overall, 179 eyes (171 patients) were included; 93 had a 12-month follow-up. Thirty-four eyes (19%) had ELM/EZ damage after surgery; in nine eyes (5%), ELM/EZ damage persisted at 12 months. Phacoemulsification during PPV (odds ratio = 6.97; P = 0.007) and ELM/EZ damage before PPV (odds ratio = 6.91; P = 0.007) were risk factors for postoperative ELM/EZ disruption. Thicker outer nuclear layer (P = 0.002), thicker ectopic inner foveal layer (P < 0.001), and higher endoillumination power (P = 0.03) were associated with slower visual recovery. Inner limiting membrane peeling (P = 0.04) was associated with slower anatomical recovery.

CONCLUSION

Cataract extraction and outer retinal damage before PPV are associated with higher risk of photoreceptor damage postoperatively. The rate of visual improvement varies as a function of retinal layers' distortion before surgery; additional retinal manipulation slows restoration of the macular anatomy.

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

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

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

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

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

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.

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.

Optical coherence tomography biomarkers as predictive factors for postoperative visual acuity in patients with epiretinal membrane treated with vitrectomy

BACKGROUND:

The purpose of this retrospective study was to evaluate potential predictive factors of postoperative visual outcome in patients with idiopathic epiretinal membrane (iERM), treated with pars plana vitrectomy (PPV).

METHODS:

Participants in the study were 46 patients diagnosed with iERM, who underwent PPV. Best-corrected visual acuity measurement and spectral domain-optical coherence tomography (OCT) were performed at baseline (preoperatively), and at months 6 and 12 postoperatively. Demographic characteristics and OCT parameters were assessed as potential predictive factors for postoperative visual outcome.

RESULTS:

Increasing age, retinal thickness, presence of disorganization of inner retinal layers, ellipsoid zone disruption, and presence of vitreomacular traction were found to be negatively associated with postoperative visual acuity. Gender, presence of subretinal fluid, cysts in the inner or outer nuclear layer, and hyperreflective foci were not found to affect visual acuity. There was statistically significant improvement in visual acuity and central retinal thickness between baseline and months 6 and 12 in the study sample.

CONCLUSIONS:

It is important to determine predictive factors for visual outcome, so as to inform patients about prognosis and help in the decision-making of patients' management.

Disorganization of Retinal Inner Layers as a Biomarker for Idiopathic Epiretinal Membrane After Macular Surgery-The DREAM Study

PURPOSE

Epiretinal membrane (ERM) can cause distortion and disorganization of all inner retinal layers. The purpose of our study was to evaluate the extent of disorganization of the retinal inner layers (DRIL) and to investigate its predictive value for visual outcome in cases of idiopathic ERM that were treated by pars plana vitrectomy (PPV) and ERM peeling.

DESIGN

Multicenter international retrospective case series.

METHODS

In 90 eyes from 90 patients with idiopathic ERM treated by PPV and membrane peeling with 12-month follow-up, optical coherence tomography (OCT) scans previous to surgery were evaluated for presence and severity of DRIL, central foveal subfield thickness (CST), maximal retinal thickness (MRT), presence of intraretinal cystoid changes and subretinal fluid, and integrity of the inner/outer segment layer and of the interdigitation zone. Best-corrected visual acuity (BCVA), CST, and MRT were recorded at baseline and at 3, 6, and 12 months after surgery. Correlations between baseline OCT measures (DRIL) and functional and visual outcome were analyzed. Main outcome measures are presence and severity of DRIL at baseline; anatomic and functional outcomes after 3, 6, and 12 months; and the correlation between DRIL and baseline characteristics and outcome measures.

RESULTS

Patients without and with mild DRIL had a significantly better baseline BCVA compared with patients with severe DRIL (0.61 ± 0.13, 0.56 ± 0.23, 0.73 ± 0.20 [logMAR], respectively). BCVA, CST, and MRT at baseline were statistically significantly correlated with DRIL severity (P = .003, P < .001, and P < .001, respectively). DRIL status before surgery showed a statistically significant interaction with change in BCVA, CST, and MRT over 12 months (P < .001 for all). Patients without and with mild DRIL gained a mean of 3 lines of vision after 12 months, in contrast to 1 line in patients with severe DRIL.

CONCLUSIONS

DRIL grading correlates with functional and anatomic measures in patients with idiopathic ERM and could serve as a biomarker to predict outcome after surgery. Patients with severe DRIL have limited benefits from surgery. This should be considered in the decision process whether to perform ERM peeling in this patient group.