To date, mammalian retinal ganglion cells have been studied quite well, and their diversity, development, and connections have been clarified. Fifty subtypes of these cells have already been identified, each of which optimally encodes unique visual capabilities and projects visual information to various targets in the brain, where it is decoded. Some types of ganglion cells express the photopigment melanopsin (Opn4), which makes them directly sensitive to light. In this review, we discuss the diversity of ganglion cells, their characteristics and differences, and describe the structure of retinal neurons and the synaptic processes that occur in them. Since the quality of human life is seriously affected by retinal diseases that can lead to vision loss, scientists are paying close attention to the causes of visual clarity and quality and the role of retinal ganglion cells in this process, conducting multidirectional research using new methods and different objects for study.