Visual electrophysiological tests provide information about the functional integrity of the pigment epithelium (Electrooculogram or EOG), the photoreceptors and inner layers of the retina (electroretinogram or ERG), and the optic nerve and occipital cortex (Visual Evoked Potential or VEP). The information is objective and independent from the voluntary response of the patient and thus is especially useful for non-cooperative patients and infants. The multifocal ERG technique provides reliable parameters for the accurate evaluations of diseases and their different treatment modalities existing and emerging.