Schisis of the Retinal Nerve Fiber Layer in Epiretinal Membranes

American Society of Retina Specialists Clinical Practice Guidelines on Multimodal Imaging for Retinal Disease

Purpose: Advancements in retinal imaging have augmented our understanding of the pathology and structure-function relationships of retinal disease. No single diagnostic test is sufficient; rather, diagnostic and management strategies increasingly involve the synthesis of multiple imaging modalities. Methods: This literature review and editorial offer practical clinical guidelines for how the retina specialist can use multimodal imaging to manage retinal conditions. Results: Various imaging modalities offer information on different aspects of retinal structure and function. For example, optical coherence tomography (OCT) and B-scan ultrasonography can provide insights into the microstructural anatomy; fluorescein angiography (FA), indocyanine green angiography (ICGA), and OCT angiography (OCTA) can reveal vascular integrity and perfusion status; and near-infrared reflectance and fundus autofluorescence (FAF) can characterize molecular components within tissues. Managing retinal vascular diseases often includes fundus photography, OCT, OCTA, and FA to evaluate for macular edema, retinal ischemia, and the secondary complications of neovascularization (NV). OCT and FAF play a key role in diagnosing and treating maculopathies. FA, OCTA, and ICGA can help identify macular NV, posterior uveitis, and choroidal venous insufficiency, which guides treatment strategies. Finally, OCT and B-scan ultrasonography can help with preoperative planning and prognostication in vitreoretinal surgical conditions. Conclusions: Today, the retina specialist has access to numerous retinal imaging modalities that can augment the clinical examination to help diagnose and manage retinal conditions. Understanding the capabilities and limitations of each modality is critical to maximizing its clinical utility.

EPIRETINAL MEMBRANE WITH FOVEAL HERNIATION: Visual and Surgical Outcomes

PURPOSE

Foveal herniation occurs when neuroretinal tissue protrudes through and above the level of an epiretinal membrane. This study describes the visual symptoms and spectral domain optical coherence tomography findings associated with foveal herniation and evaluates the postoperative visual, anatomical, and surgical outcomes.

METHODS

A multicenter retrospective review of patients diagnosed with epiretinal membrane identified 59 patients with preoperative foveal herniation on spectral domain optical coherence tomography. Data regarding visual symptoms, preoperative and postoperative best-corrected visual acuity (BCVA), central retinal thickness, macular volume, and size of foveal herniation were collected, and statistical analysis was performed.

RESULTS

A total of 58 of the 59 patients with foveal herniation underwent surgical epiretinal membrane peeling, with foveal contour restored in 53.5% of patients after surgery. Average BCVA improved from 20/80 to 20/40 Snellen equivalent at most-recent postoperative visit (P < 0.0001). The average central retinal thickness decreased from 632 µm to 432 µm (P < 0.0001) and the average macular volume decreased from 11.3 mm3 to 9.5 mm3 (P < 0.0001) at 3 months postoperatively. Preoperatively, greater herniation height was associated with worse BCVA (P = 0.008), greater central retinal thickness (P = 0.01), retinoschisis, cystoid macular edema, foveolar detachment, ellipsoid zone abnormality, and external limiting membrane abnormalities (P < 0.05). Postoperatively, there was a decrease in retinoschisis, cystoid macular edema, foveolar detachment, ellipsoid zone, and external limiting membrane abnormality (P < 0.05) on spectral domain optical coherence tomography.

CONCLUSION

Patients with larger foveal herniation height had greater preoperative central retinal thickness, worse preoperative and postoperative BCVA, and more intraretinal abnormalities on spectral domain optical coherence tomography. Surgical epiretinal membrane peeling in patients with foveal herniation resulted in a significant improvement in patients' BCVA and microstructural abnormalities.

Large Internal Limiting Membrane Tears: Prevalence, Clinical Characteristics, and Surgical Utility

PURPOSE

To describe the prevalence, clinical and imaging characteristics, and surgical utility of large internal limiting membrane (ILM) tears in eyes with epiretinal membrane (ERM).

DESIGN

Retrospective interventional case series.

METHODS

This was a single-institution study including 71 eyes of 70 consecutive patients that underwent ERM peeling by a single vitreoretinal surgeon between 2016 and 2019. Demographic and clinical data were collected from the medical record. ERMs and large ILM tears were identified and analyzed on multimodal imaging. The main outcome measures were the prevalence and characteristics of large ILM tears in eyes undergoing ERM peeling.

RESULTS

Large ILM tears were present in 23 of 71 eyes (32.4%) with ERM that underwent surgical management. A review of patients with ERM during the same period who did not undergo surgical management found large ILM tears in 8 of 100 eyes (8.0%). Large ILM tears were commonly associated with other signs of ERM-induced retinal traction, including retinal nerve fiber layer schisis in 20 of 23 eyes (87.0%), inner retinal dimpling in 8 of 23 eyes (34.8%), and discrete paravascular red lesions in 16 of 19 eyes (84.2%). In all eyes stained with brilliant blue G, the preoperative diagnosis of large ILM tear was confirmed and the scrolled ILM edge was used successfully to initiate ILM peeling.

CONCLUSIONS

Large ILM tears are often present in eyes undergoing surgery for ERM and are likely caused by ERM contracture. Careful preoperative identification of these tears is helpful for surgical planning because the scrolled flap of ILM provides a convenient and safe "handle" for initiating membrane peeling.

Visual, Anatomic Outcomes, and Natural History of Retinal Nerve Fiber Layer Schisis in Patients Undergoing Epiretinal Membrane Surgery

PURPOSE

To evaluate the anatomic and visual outcomes of patients with idiopathic epiretinal membranes (ERMs) complicated by schisis of the retinal nerve fiber layer (sRNFL) in routine clinical practice.

DESIGN

Retrospective case-control study.

PARTICIPANTS

Patients undergoing idiopathic ERM surgery at Cole Eye Institute from 2013 to 2021.

METHODS

Patients were grouped by the presence or absence of sRNFL before surgery. Preoperative and postoperative data were collected regarding visual acuity (VA), changes in central subfield thickness (CST) over time, and presence of cystoid macular edema.

MAIN OUTCOME MEASURES

Frequency of sRNFL in patients undergoing idiopathic ERM surgery.

RESULTS

Overall, 48 (53.9%) of 89 patients presented with sRNFL. Schisis of the retinal nerve fiber layer patients presented with significantly decreased VA compared with those without (58.63 ± 12.48 vs. 67.68 ± 7.84 ETDRS letters, P < 0.001, respectively). At the final follow-up after ERM removal, there was no significant difference in final VA in patients with sRNFL compared with those without (71.16 ± 2.93 vs. 74.11 ± 2.76, P = 0.467). At presentation, patients with sRNFL had greater CST than those without (454 ± 10.01 vs. 436 ± 0.23, P = 0.23). This difference persisted at the 90-day follow-up after ERM removal (402 ± 8.08 vs. 375 ± 10.19 μm, P = 0.043). The resolution of sRNFL was reported at postoperative week 1 in 30 (96.7%) of 31 cases.

CONCLUSIONS

Schisis of the retinal nerve fiber layer is a microstructural feature in > 50% of idiopathic ERMs in routine clinical practice and carries visual significance on presentation and anatomic significance postoperatively.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Clinical and morphological characteristics of patients with idiopathic epiretinal membrane with foveal herniation

PURPOSE

To analyse the clinical and morphological characteristics of eyes with idiopathic epiretinal membrane (iERM) and foveal herniation (FH).

METHODS

Clinical findings and OCT features of patients with iERM and FH were retrospectively analysed. Primary outcome were changes of the best-corrected-visual-acuity (BCVA) and OCT features from baseline to the last visit. FH patients were divided into two groups based on herniated layers: ganglion cell complex (GCC)-group and sub-GCC-group. Surgical outcome was also assessed.

RESULTS

In this study, 3882 patients with iERM were screened, of whom 51 (1.3%) were identified with FH. The GCC-group (n = 16) had a better baseline BCVA and thinner central foveal thickness (CFT) in comparison to the sub-GCC-group (n = 35) but without statistical significance (p = 0.330, p = 0.417, respectively). The postoperative BCVA-improvement was similar between the two groups (p = 0.280). Fibrillary surface changes were detected in 42/51 (82.3%) patients, significantly more often in the sub-GCC group (p = 0.020). The baseline BCVA was a predictive factor for the postoperative vision change.

CONCLUSION

FH presents with a unique macular morphology in eyes with iERM. Affected eyes experience varying visual disturbances based on the involvement of the inner retinal layers in the foveal herniation. Macular surgery is successful in restoring vision, even though foveal morphology does not fully recover.

Dissociated optic nerve fiber layer-like appearance indicating an internal limiting membrane defect associated with an epiretinal membrane: two case reports

Background

We report for the first time a way to predict the 2-dimensional extension of an internal limiting membrane (ILM) defect by detecting the area with dissociated optic nerve fiber layer (DONFL)-like spots in the preoperative optical coherence tomography (OCT) en-face images.

Case presentations

Case 1 was a 67-year-old man with metamorphopsia and decreased vision in his right eye. His best-corrected visual acuity (BCVA) was 20/100, with a pterygium, a moderate nuclear cataract, and an epiretinal membrane (ERM). Case 2 was a 73-year-old man with metamorphopsia and decreased vision in his left eye. His BCVA was 20/25, with a moderate nuclear cataract and an ERM. Both patients underwent simultaneous cataract surgery and pars plana vitrectomy with ERM and ILM peeling. Brilliant Blue G staining, performed before ERM and ILM peeling, revealed an unstained area. A careful evaluation of the area showed that it was not covered by either the ERM or ILM. A postoperative evaluation of the preoperative OCT images obtained from these cases showed DONFL-like low-brightness spots in the ILM defect area on the OCT en-face images.

Conclusions

OCT en-face images may indicate the area of the ILM defect. To avoid iatrogenic damage to the retinal nerve fiber layer by touching/pinching it with forceps, detecting areas with DONFL-like spots in the preoperative OCT en-face images may be useful to predict an ILM defect.

Structure-function analysis for macular surgery in patients with coexisting glaucoma

PURPOSE

To develop methods to assess the effects of epiretinal membranes (ERM) and macular holes (MH) coexisting with glaucoma on pre-operative retinal structure and function and evaluate post-operative outcomes.

METHODS

Seven eyes of 7 patients with glaucoma, 6 with ERMs and 1 with MH, were enrolled; 4 underwent vitrectomy for ERM and one for MH. Visual fields (VFs) and optical coherence tomography (OCT) scans were obtained pre- and post-operatively. The 10-2VF deviation map was overlayed on ganglion cell and inner plexiform layer (GCL + IPL) and retinal nerve fiber layer (RNFL) deviation maps derived from OCT macula and disc cube scans. Optic nerve circle scans were obtained to assess RNFL thickness, and OCT b-scans associated with VF defects were compared pre- and post-operatively.

RESULTS

Examination of pre-operative VFs and OCT scans showed the importance of determining the extent to which glaucomatous damage contributed to VF loss; verifying automated segmentation of the GCL + IPL and RNFL; and assessing foveal anatomy. Evaluation of post-operative structure-function outcomes required correction of magnification changes in OCT scans and repeated follow-up visits to clarify the origin of VF changes.

CONCLUSIONS

Pre-operative comparisons of VFs and OCT scans may be beneficial in guiding surgical planning, and evaluating outcomes, in eyes with glaucoma undergoing macular surgery.

Activation of quiescent polypoidal choroidal vasculopathy after membrane peeling vitrectomy for epiretinal membrane: a case report

BACKGROUND

Regular membrane peeling vitrectomy for epiretinal membrane (ERM) patients seldom causes large pigment epithelial detachment (PED). We presented an unusual case of the activation of quiescent polypoidal choroidal vasculopathy (PCV) after membrane peeling vitrectomy for ERM, with an uneven therapeutic process.

CASE PRESENTATION

A 75-year-old female patient complained of metamorphopsia in her left eye for 2 years. Her best-corrected visual acuity was 20/160 with a moderate nuclear cataract. An irregular ERM and slight PED were shown in optical coherence tomography (OCT). No obvious orange-red lesion was detected. The patient underwent vitrectomy + ERM peeling + cataract surgery. After the operation, large PED emerged, and indocyanine green angiography (ICGA) confirmed PCV. Four monthly injections of intravitreal ranibizumab were administered, but PED persisted. After focal laser therapy targeted to the polyps combined with ranibizumab treatment, PED was absorbed.

CONCLUSIONS

Careful evaluation for PCV before membrane peeling vitrectomy for ERM is important, as indolent PCV may be activated postoperatively. Anti-VEGF therapy accompanied by laser photocoagulation may be more effective for PCV polyps located away from the fovea.

Foveal configurations with disappearance of the foveal pit in eyes with macular pucker: Presumed role of Müller cells in the formation of foveal herniation

Many eyes with macular pucker are characterized by a centripetal displacement of the inner foveal layers which may result in a disappearance of the foveal pit. In this retrospective case series of 90 eyes with macular pucker of 90 patients, we describe using spectral-domain optical coherence tomography different foveal configurations with ectopic inner foveal layers, document the relationship between posterior vitreous detachment (PVD) and idiopathic epiretinal membrane (ERM) formation and spontaneous and postoperative morphological alterations of the fovea, and propose an active role of Müller cells in the development of foveal herniation. We found that ERM were formed during or after partial perifoveal PVD, or after foveal deformations caused by tissue edema. The ERM-mediated centripetal displacement of the inner foveal layers and in various eyes anterior hyaloidal traction caused a disappearance of the foveal pit and an anterior stretching of the foveola with a thickening of the central outer nuclear layer (ONL). After the edges of the thickened inner layers of the foveal walls moved together, continuous centripetal displacement of the inner foveal layers generated a bulge of the fovea towards the vitreous (foveal herniation). Macular pseudoholes with a herniation of the inner foveal layers show that the outer layer of the protruding foveal walls is the outer plexiform layer (OPL). If the ERM covered the foveal walls and parafova, but not the foveola, the inner layers of the foveal walls were not fully centripetally displaced and the foveal pit was present. The visual acuity of eyes with ectopic inner foveal layers was inversely correlated with the thickness of the foveal center. Spontaneous morphological alterations after disappearance of the foveal pit may include the development of cystoid macular edema or additional thickening of the foveal tissue and foveal herniation. The foveal configuration with ectopic inner layers of the foveal walls and a thick central ONL persisted over longer postoperative time periods. The data show that the centripetal displacement of the inner foveal layers in eyes with macular pucker, which results in a disappearance of the foveal pit, may also generate foveal herniation which is suggested to be caused by contraction of Müller cell processes in the OPL. The centripetal displacement of the inner foveal layers and the formation of foveal herniation are suggested to reverse the foveal pit formation during development.

Long-Term Outcome of Epiretinal Membrane Surgery in Patients with Internal Limiting Membrane Dehiscence

PURPOSE

To identify the effect of internal limiting membrane (ILM) dehiscence on surgical outcomes in eyes that have undergone epiretinal membrane (ERM) removal.

METHODS

Consecutive eyes with performed vitrectomy for ERM removal were included. Subjects were divided into two groups: patients with ILM dehiscence (group 1) and without ILM dehiscence (group 2). The best-corrected visual acuity (BCVA) and retinal layer thickness before and after surgery were compared between the two groups.

RESULTS

A total of 86 eyes were enrolled. Forty-six eyes (53.5%) showed ILM dehiscence before surgery. The baseline BCVAs were 0.46 ± 0.29 and 0.45 ± 0.25 in groups 1 and 2, respectively (p = 0.801). The BCVAs at 3, 6, and 12 months after surgery differed significantly between the two groups. The subfoveal thickness and inner retinal layer thickness (IRLT) of group 1 vs. 2 were 507.4 ± 80.0 vs. 417.6 ± 63.6 μm, and 270.2 ± 74.3 vs. 182.6 ± 60.4 μm, respectively (both p < 0.001). These differences between the groups remained significant until 12 months after surgery. In multivariate analyses, the location of ILM dehiscence (B = -0.105, p = 0.034) and final IRLT (B = 0.001, p = 0.046) were significant factors affecting the final BCVA.

CONCLUSIONS

ILM dehiscence is a relatively common finding and associated with preoperative and postoperative increased IRLT, which results in worse surgical outcomes compared to the absence of ILM dehiscence in patients with ERM. Additionally, the final BCVA was significantly affected by its location and final IRLT in patients with ILM dehiscence.

Bare retinal nerve fiber layer and internal limiting membrane tear associated with epiretinal membrane: OCT findings and visual outcomes

PURPOSE

This study aims to describe spectral-domain optical coherence tomography (OCT) characteristics and assess surgical outcomes for bare retinal nerve fiber layer (RNFL) and internal limiting membrane (ILM) tear associated with the epiretinal membrane (ERM).

METHODS

This retrospective study comprised 158 consecutive patients with idiopathic ERM with (group A) or without (group B) bare RNFL (19 and 139 patients, respectively) who underwent vitrectomy between March 2016 and May 2019. Surgical videos and pre- and postoperative OCT images were reviewed to characterize bare RNFL and ILM tear and analyze postoperative visual outcomes.

RESULTS

Typically, the torn ILM is seen as a mono- or multi-layered thin scrolled membrane in OCT, correlated frequently with areas of RNFL schisis. On the near-infrared fundus images, a hypo-reflective band corresponding to rolled-up edge of torn ILM and ERM was identified. The bare RNFL area was located adjacent to and peripheral to this band and showed a less-wrinkled retina preoperatively. Mean logMAR BCVA and central foveal thickness (CFT) progressively improved in both groups. However, group A had greater mean CFT change than group B (P = 0.001).

CONCLUSION

Typical appearances of bare RNFL and ILM tear associated with ERM were identified. Thorough evaluation of preoperative OCT is important for vitreoretinal surgeons to recognize bare RNFL and ILM tear to minimize surgical trauma.