The Impact of the Ectopic Inner Foveal Layer with Preserved Foveal Contour on Retinal Microvasculature Changes after Epiretinal Membrane Removal

PURPOSE: To evaluate the long-term effects of preoperative ectopic inner foveal layer (EIFL) with preserved foveal contour on postoperative retinal microvascular changes in patients with epiretinal membrane. METHODS: Patients were divided into two groups based on EIFL presence: Group 1 without EIFL and Group 2 with EIFL. Superficial and deep vessel densities (SVD and DVD), corresponding to the superficial and deep vascular complexes, were quantitatively assessed using OCT angiography. RESULTS: The SVD at baseline, 1, 3, 6, and 12 months were 27.9 ± 7.7, 27.6 ± 8.3, 25.9 ± 7.8, 26.1 ± 7.0, and 24.9 ± 8.0 % in Group 1, respectively (P = 0.075), and 31.6 ± 7.3, 28.0 ± 6.3, 26.7 ± 5.6, 25.4 ± 5.7, and 22.9 ± 5.6 % in Group 2, respectively (P < 0.001). The DVDs were 21.9 ± 4.6, 22.9 ± 4.5, 23.6 ± 5.1, 24.2 ± 4.0, and 23.6 ± 4.7 % in Group 1, respectively (P = 0.277), and 20.6 ± 4.7, 22.8 ± 4.2, 23.2 ± 3.7, 23.6 ± 5.0, and 23.4 ± 3.8 % in Group 2, respectively (P = 0.003). In the multivariable analysis, baseline BCVA was significantly associated with changes in BCVA in Group 1, while in Group 2, baseline BCVA and DVD showed significant associations with BCVA changes. CONCLUSIONS: Patients with EIFL and preserved foveal contour demonstrated more prominent alterations in retinal microvasculature after surgery, and these changes, especially within the deep vascular complex, are considered to play an important role in visual improvement.