Development of a Normative Database for Multifocal Electroretinography in the Context of a Multicenter Clinical Trial

The aim of this study is to present the largest normative database using multifocal electroretinography (mfERG) in the context of a multicenter clinical trial.

This investigational study included 156 eyes from 78 Caucasian subjects aged 45-70 years without known ophthalmic disease or diabetes mellitus; the subjects were recruited from 11 clinical sites in the setting of the EUROCONDOR project. Standardized mfERG acquisition (103 hexagons per eye) was established based on the International Society of Clinical Electrophysiology in Vision. At least one technician per site received both specialized training and certification. The main variables that could have influenced the results were considered in the analyses.

The normative database was based on 111 eyes. The overall mean P1-implicit time (IT) was 33.94 ± 1.70 ms, and the mean P1 amplitude was 30.58 ± 5.20 nV/deg2. Age and gender were independently related to predictors of P1-IT but not of P1 amplitude. The responses that were averaged for the 6 rings showed a longer P1-IT time in the fovea, decreasing progressively to the parafovea and perifovea. By contrast, P1 amplitude values sharply decreased with retinal eccentricity.

This normative database can be used as a comparative index of expected normal values in the clinical setting and for examining the effect of studies testing neuroprotective agents.