Purpose: To evaluate the possible prognostic value of preoperative individual retinal layer thicknesses measured by an automated algorithm from spectral domain optical coherence tomography and visual acuity or improvement after epiretinal membrane surgery. Methods: Data from 76 eyes with idiopathic epiretinal membrane that underwent pars plana vitrectomy for idiopathic epiretinal membrane removal were analyzed. The preoperative thicknesses of the ganglion cell layer, inner plexiform layer, and other layers were measured using the Iowa Reference Algorithm. Each retinal layer thickness and its ratio of the central foveal thickness were compared between eyes with (Group 1) or without (Group 2) 2 or more Snellen lines of visual improvement at 3, 6, and 12 months after surgery. Results: Higher mean central foveal thickness/ganglion cell layer ratio and symptom duration of ≤1 year were significantly more common in Group 1 (P 0.03 and 0.04, respectively). After adjusting for age and symptom duration, lens status, and preoperative visual acuity, higher central foveal thickness/ganglion cell layer ratio was associated with ≥2 lines of visual improvement after surgery (odds ratio: 6.57, 95% confidence interval: 1.29-33.40). Conclusion: The preoperative inner retinal layer changes may have a role independent of outer retinal layer parameters in the visual prognosis after epiretinal membrane peeling.