Purpose: To determine the long-term changes in the regional macular thickness after idiopathic epiretinal membrane (ERM) excision and to determine whether there were correlations between the pre- and postoperative central macular thickness and the best-corrected visual acuity (BCVA).
Methods: This was a prospective, interventional case series study of 53 eyes of 53 patients that underwent ERM removal with internal limiting membrane (ILM) peeling. Examinations were performed before, 1, 2, 3, 6, 9, 12, 24, 36, 48, and 60 months after the surgery. The average macular thicknesses in nine sectors outlined by the Early Treatment Diabetic Retinopathy Study were measured by spectral-domain optical coherence tomography. The final macular thicknesses of nine sectors of the 35 patients were compared with that of the normal fellow eyes.
Results: All patients were followed for 36 months, and 21 patients were followed for 48 months. The thicknesses of all sectors progressively decreased for 48 months. The macula at 48 months was thinner than at 36 months (P < 0.0001-0.037) in all sectors. The final central and nasal sectors were significantly thicker than that of the fellow eyes. The final inner and outer temporal sectors were significantly thinner compared with the fellow eyes. There was no significant difference in the other sectors. The pre- and postoperative central macular thickness was significantly correlated with the postoperative BCVA at each examination.
Conclusions: A progressive thinning of the macula occurs with regional differences for at least 48 months. The temporal sector becomes thinner than the normal thickness.