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.