We evaluated the retinal electrophysiologic function in both the detached and attached areas of eyes with retinal detachment, and assessed the functional recovery of these areas after surgery by quantifying the results obtained from multifocal electroretinograms. Multifocal electroretinographic recordings and central 0 degrees to 30 degrees visual field tests were performed preoperatively and 2 weeks 1, 3 and 6 months postoperatively in 12 patients with unilateral retinal detachment. Each patient's response to the multifocal electroretinogram and the visual field test was classified into two groups: group A, the response from the attached area; and group B, that from the detached retinal area. Individual mean deviation and percentage mean deviation were calculated for each group. All retinal detachments were successfully reattached by the conventional scleral buckling method. The retinal sensitivity in the visual field test of all the patients in group B greatly improved. However, the percentage mean deviation in the response density of the multifocal electroretinogram in group B was -81% preoperatively and -63% at 6 months postoperatively. Thus, the improvement was confined within narrow limits. The response density of the multifocal electroretinogram in group A was very low, and never improved beyond -50% of percentage mean deviation. In the eyes with retinal detachment, clectroretinogram response in both the attached and detached areas was more disturbed than predicted by means of the visual field test during the course of this study.