Transient increase of flicker electroretinograms after combined cataract surgery and vitrectomy for idiopathic epiretinal membrane.

To determine the characteristics of the changes in the amplitude of the flicker electroretinograms (ERGs) after combined cataract surgery and vitrectomy for an idiopathic epiretinal membrane (ERM). To accomplish this, we conducted a prospective study on 20 patients. Flicker ERGs and central macular thickness (CMT) were measured before the surgery (baseline), and at 1 week, 1 month, 3 months, and 6 months postoperatively. The mean amplitude of the flicker ERGs increased significantly by 63.5% at 1 week after surgery (P < 0.001) and then gradually decreased. The amplitude at 6 months was not significantly different from the baseline amplitude. This transient increase in the flicker ERG amplitudes after ERM surgery suggests that electrophysiologic evaluations of the therapeutic effects of vitrectomy should be performed 6 months postoperatively. The mean CMT decreased significantly at 1 week postoperatively (P < 0.001) and continued to decrease progressively over six months. The relative increase of amplitude at 1 week was significantly associated with the relative decrease of CMT at 6 months, and evaluation of retinal functional changes at 1 week may be able to predict the postoperative course of the ERM.