Long-term Follow-up Results of Idiopathic Epiretinal Membrane Removal in the Eyes with Ectopic Inner Foveal Retinal Layers

PURPOSE: The purpose of this study was to evaluate pre- and perioperative factors related to time for the evolution of ectopic inner foveal layers (EIFL) following pars plana vitrectomy (PPV) for epiretinal membrane (ERM) peeling.METHODS: This retrospective study included 81 consecutive eyes with idiopathic ERM that underwent vitrectomy surgery. Standard PPV + internal limiting membrane peeling was performed in all cases. A comprehensive ophthalmic examination was performed for all patients before and 1, 3, 6, and 12 months, and the last follow-up after surgery. We observed the postoperative improvement in EIFL severity in the short-term and longest follow-up and evaluated anatomical and functional improvement. Several parameters were assessed using the multivariate COX proportional hazard analysis.RESULTS: Eighty patients (81 eyes) with a mean age of 70.33 +/- 7.75 years were followed for a mean of 34.37 +/- 23.61 months, and 55.5% of eyes (45 eyes) with EIFL ERM showed improvement of foveal contour to a better stage at the last follow-up. The median estimated time for evolving to a better stage was 29.73 months for stage 2, 49.68 months for stage 3, and 38.67 months for stage 4 (P = 0.001, log-rank test). The severity of EIFL was the only significant factor for time to evolution of EIFL ERM to a better stage, where the eyes with stage 4 EIFL ERM showed faster foveal contour improvement compared to those with stage 3 EIFL ERM (hazard ratio: 0.317, 95% confidence interval = 0.164-0.615, P = 0.001).CONCLUSION: On assessing preoperative factors, the preoperative EIFL stage emerged as the sole significant factor for EIFL ERM improvement to a better disease stage. This study reports some of the longest follow-up durations for patients undergoing PPV for EIFL ERM, and both functional and anatomical improvements were observed across all stages of EIFL, including in the advanced stage 4 EIFL ERM.