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.

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) diagnosed with idiopathic epiretinal membrane (iERM) patients who were peeled up only ERM in eyes with EIFL.Materials and Methods: Patients diagnosed with iERMs who have undergone PPV including only ERM peeling were enrolled into the study; and follow-up findings were recorded at baseline, months 3, 6, 12, and final examinations, retrospectively. EIFL was divided into four grades from mild to severe. Pre- and postoperative anatomical changes were measured by spectral domain optical coherence tomography (SD-OCT) imaging method. 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 EIFL (mild to severe) were included in the study. The higher thickness of EIFL was significantly correlated with lower baseline BCVA (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 final visit, observed in 8 eyes (23 %) in early stage (stage 2) of iERMs. Above all, a strong positive correlation was found between EIFL thickness and ERM recurrence rate (r=0.876, p <0.001). Recurrence ERM was detected in 27 eyes, which were found in 2 eyes (%7) at stage 1, 3 eyes (%9) at stage 2, 10 eyes (%23) at stage 3, and 12 eyes (%33) at stage 4 (p<0.001).Conclusion: A negative relationship was found between the severity of EIFL and postoperative anatomical and visual recovery. In terms of surgical timing, early stages (stage 1 and 2) may be preferred for providing good anatomical and visual recovery and low recurrence rate following surgery. In relation to further anatomical and visual yields, additional internal limiting membrane peeling may not be an essential procedure for early grades of iERMs (stage 1 and 2).