In this study, we evaluated the thickness of each retinal layer using spectral-domain optical coherence tomography (OCT) and investigated the correlation between the thickness of each retinal layer and postoperative visual acuity in eyes with idiopathic epiretinal membrane (ERM).

This retrospective study included 46 eyes from 46 patients with idiopathic ERM who underwent pars plana vitrectomy. Each retinal layer thickness was measured by spectral-domain OCT before operation and at 1, 3, and 6 months after operation. The thickness of each retinal layer was evaluated in the control group before the operation. We performed an analysis of the changes in thickness of each retinal layer at 6 months after operation and then investigated the correlation between the retinal layer thickness and visual improvement.

Preoperatively, the thickness of the retinal nerve fiber layer (RNFL) in the ERM group showed more increased compared with that in the control group, and the thickness of photoreceptors and retinal pigment epithelium were decreased compared to those in the control group. At 6 months after the operation, thickness changes were reduced at the RNFL, ganglion cell layer (GCL), inner plexiform layer (IPL), GCL-IPL complex, and outer plexiform layer, while the photoreceptor layer increased compared with the values preoperatively. Differences in the preoperative thickness of GCL between the two groups had a significant correlation with postoperative visual acuity (r = 0.477, p = 0.008).

Differences in preoperative thickness of the GCL between the two groups had a significant correlation with postoperative visual acuity. The greater was the thickness of the GCL, the worse was the visual outcome.