Choroidal Thickness Changes Following Vitrectomy in Epiretinal Membrane Based on the Optical Coherence Tomography Pattern

ABSTRACT

PURPOSE: To analyze the influence of morphological classification in epiretinal membrane (ERM) based on surgical outcomes and optical coherence tomography (OCT) of the postoperative choroidal thickness. METHODS: This observational study included 122 eyes with ERM who underwent vitrectomy. Using OCT, the preoperative ERM was classified into six types cystoid macular edema (CME), convex, flat, normal foveal contour (Normal), pseudolamellar hole (PLH), and vitreomacular traction (VMT). The preoperative multifocal electroretinogram (mfERG), postoperative change in subfoveal choroidal thickness (SCT), central macular thickness (CMT), and best-corrected visual acuity (BCVA) were compared. RESULTS: Preoperative subfoveal choroidal thickness increased in the VMT type compared to the fellow eye (207 µm vs. 234 µm, p = 0.028). Choroidal thickness decreased in all types at 12 months after vitrectomy (all, P < 0.05). There was a positive linear correlation between the mfERG and the preoperative BCVA (p = 0.001). The initial visual acuity was best in the Normal type followed by the flat, PLH, convex, CME, and VMT types (p = 0.001). The final visual acuity was the best in the Normal type, followed by the PLH, Flat, VMT, Convex, and CME types (p = 0.030). Gas tamponade during the surgery did not affect the surgical outcomes of the CMT (p = 0.458), BCVA (p = 0.550), and SCT (p = 0.127). CONCLUSIONS: Preoperative SCT increased only in the VMT type, but choroidal thickness decreased in all types after vitrectomy, regardless of the preoperative morphology.