To report the reproliferation of membrane after a spontaneous separation in a patient with idiopathic epiretinal membrane (ERM).

A 62-year-old woman complained of metamorphopsia in the left eye. Her vision without correction was 0.8. On fundus examination, the epiretinal membrane was covering the fovea with posterior vitreous detachment. Optical coherence tomography (OCT) showed the ERM and thickened macula. Retinal break, intraocular inflammatory disease, and retinal vascular disease were not noted. We diagnosed her with idiopathic ERM and followed up regularly. At month 7, a partial separation of the membrane from the retinal surface was noted. At month 12, complete spontaneous separation of the ERM from the macula except that in the temporal area was accompanied by improvement of vision to 1.0. OCT, showing recovery of the fovea contour. However, her corrected vision decreased to 0.7 at month 17, and the ERM was again observed to cover the macula. Thickening of the ERM progressed further, and her corrected vision decreased to 0.5 at month 21.

Spontaneous separation of membrane is a rare phenomenon in idiopathic ERM. Reproliferation of membrane can develop and induce visual impairment. Therefore, regular examination is recommended in patients with spontaneous separation of membrane.