Multifocal electroretinogram in normal emmetropic subjects: Correlation with optical coherence tomography

AIM OF THE STUDY To establish the normative database for multifocal electroretinogram (mfERG) parameters in a normal emmetropic population. To correlate the data so obtained with the central macular thickness obtained using the optical coherence tomography (OCT) scan. MATERIALS AND METHODS mfERG data were obtained from 222 eyes of 111 emmetropic subjects. The amplitude (nv/deg 2 ) and implicit times (ms) of the first-order kernel mfERG responses (N1, P1, and N2 waves) were obtained and grouped into five rings (Ring 1: Central 2°, Ring 2: 2-5°, Ring 3: 5-10°, Ring 4: 10-15°, Ring 5: >15°). The central macular thickness (CMT) was obtained using the macular thickness scan protocol of the OCT. RESULTS The mfERG data obtained were used to create a normative database. The amplitudes of the mfERG waves were maximum in the fovea and progressively decreased with increasing eccentricity (P = 0.0001). The latencies of the P1 and N2 waves were longest in the central ring and progressively shortened with eccentricity (P = 0.0001). No statistically significant correlations were observed between central ring 1 parameters and the CMT. CONCLUSION This study establishes normative database for mfERG parameters in an emmetropic population. No statistically significant correlation was noted between CMT and mfERG parameters.