The outcomes of epiretinal membrane peeling in patients with foveal herniation

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.

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.

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.

Relation of anatomy with function following the surgical treatment of idiopathic epiretinal membrane: a multicenter retrospective study

PURPOSE

To investigate the prognostic factors associated with functional and anatomical outcomes and to assess the longitudinal course of visual acuity and retinal morphology after vitreoretinal surgery for idiopathic epiretinal membrane (ERM).

METHODS

This multicenter, retrospective study included a total of 634 eyes who underwent surgery for idiopathic ERM in 22 academic centers nationwide in Turkey. Data on best-corrected visual acuity (BCVA) and optical coherence tomography features (central foveal thickness (CFT), ERM and foveal contour morphology, ellipsoid zone (EZ) integrity) were collected and compared at baseline, 6-month, 12-month, and 24-month follow-ups. Prognostic factors for functional (having ≥ 20/25 Snellen BCVA) and anatomical (having normal/shallow foveal contour) recoveries after surgery were investigated by means of multivariate regression analyses. A cutoff value of preoperative BCVA optimizing functional recovery was calculated using receiver operating characteristic curve analysis.

RESULTS

At a median follow-up of 24 months, 37.4% of the eyes achieved ≥ 20/25 BCVA and 54% regained normal or shallow foveal contour. Functional recovery was more likely in eyes with better baseline BCVA and intact EZ (R² = 0.356, p < 0.001). The cutoff baseline BCVA value for good visual prognosis was 0.35 logarithm of the minimum angle of resolution (Snellen 20/44) (sensitivity 60%, specificity 85%, p < 0.001). Anatomical recovery was negatively associated with advanced age, higher baseline CFT, foveal herniation-type ERM morphology, and internal limiting membrane (ILM) peeling (R² = 0.225, p < 0.001). The negative effect of ILM peeling on anatomical recovery was not significant after the first postoperative year (p = 0.05). Mean BCVA values and foveal morphology progressively improved at each visit. Cases with convex baseline foveal contour continued to change towards normal foveal depression over 24 months of follow-up, which took longer than the eyes with shallow/flat contoured cases. One-third of eyes with severe baseline EZ defects showed recovery at follow-up and achieved significantly greater visual acuity gains than the remaining eyes with persistent defects (p < 0.001).

CONCLUSIONS

Functional and anatomical restoration of the eyes appears to be a slow process after ERM surgery. This process may take much longer in eyes with worse foveal morphology at baseline. Although photoreceptor disruption may be reversible in some eyes, full functional recovery is unlikely when it persists.