Purpose To determine anatomical and functional retinal modifications in patients with idiopathic epiretinal membrane (ERM) without objective symptoms. Methods This prospective monocentric study included 28 eyes of 28 patients with ERM having a best corrected visual acuity greater than 20/25. All patients underwent a complete ophthalmic examination, including the measurement of the visual acuity on the ETDRS scale, a macular SD‐OCT and a microperimetry at 0, 6 and 12 months. We assessed macular abnormalities on SD‐OCT namely: retinal folds, retrofoveolar deposits, cystoid cavities and external retinal layers alterations. Results At baseline the mean visual acuity was 85±4 letters, the mean macular sensitivity was 14.3±1.3 decibels, the mean macular thickness was 357±32 micrometers and the score of the SD‐OCT retinal abnormalities per patient was 2.5±0.8. At one year, the score of the SD‐OCT retinal abnormalities per patient was significantly higher: 3.3±1.3 (p=0.007). At one year, the mean visual acuity, the mean macular sensitivity and the mean macular thickness were stable at 84±5 letters (p=0.8), 14.4±1.7 decibels (p=0.8) and 356±43 micrometers (p=0.3), respectively. Conclusion This study showed an increased number of retinal lesions observed on SD‐OCT with a stable visual acuity and a stable retinal sensitivity measured with the microperimetry after one year of follow‐up.