In ophthalmology practice, new instruments are being developed every day for diagnosis and follow-up. Electrophysiological tests that examine the physiological structure of eye diseases are becoming increasingly widespread. Electrophysiological tests provide an objective assessment of the visual system. Multifocal Tests allow the topographic measurement of electrical activity at different levels of the visual system by recording responses from many visual field points in a short period of time. Multifocal ERG is based on the recording of the topographic cone responses from the 61 or 103 point of the retina. In this book, we tried to present our own cases about the most common diseases in ophthalmology practice in the context of multifocal ERG.