The most important development in ERGs is the multifocal ERG (mfERG). Erich Sutter adapted the mathematical sequences called binary m-sequences creating a program that can extract hundreds of focal ERGs from a single electrical signal. This system allows assessment of ERG activity in small areas of retina. With this method one can record mfERGs from hundreds of retinal areas in a several minutes (Sutter, 2010). ERG electrodes are used to record ERGs from the cornea from a dilated eye. Small scotomas in retina can be mapped and degree of retinal dysfunction quantified.EXAMmultier