Assessment of macular function by multifocal electroretinogram in diabetic macular edema before and after vitrectomy

The purpose of this study was to assess the effects of vitrectomy on retinal function in macular and paramacular areas in patients with diabetic macular edema (DME). Ten eyes of 9 patients with successful vitrectomy for DME were evaluated by multifocal electroretinogram (mfERG), optical coherence tomography (OCT), and visual acuity preoperatively and 1, 2, 3, 4, 5 and 6 months postoperatively. Compared with pretreatment values, the response of the positive wave (P1) in macular and paramacular areas tended to decrease in latency from the second postoperative month, and increase in amplitude at the third postoperative month. There was no significant change in response of the negative wave (N1). The tendency in the change of macular function is coincident with that of macular morphology. Therefore, The multifocal ERG may provide objective criteria for the functional evaluation of DME before and after vitrectomy.